[Federal Register Volume 81, Number 124 (Tuesday, June 28, 2016)]
[Notices]
[Pages 41934-41958]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2016-15200]
-----------------------------------------------------------------------
DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[Docket No. 150506425-6516-02]
RIN 0648-XD941
Endangered and Threatened Wildlife and Plants; Notice of 12-Month
Finding on Petition To List the Smooth Hammerhead Shark as Threatened
or Endangered Under the Endangered Species Act
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice of 12-month finding and availability of status review
document.
-----------------------------------------------------------------------
SUMMARY: We, NMFS, announce a 12-month finding on a petition to list
the smooth hammerhead shark (Sphyrna zygaena) as threatened or
endangered under the Endangered Species Act (ESA). We have completed a
comprehensive status review of the smooth hammerhead shark in response
to this petition. Based on the best scientific and commercial
information available, including the status review report (Miller
2016), we have determined that the species does not warrant listing at
this time. We conclude that the smooth hammerhead shark is not
currently in danger of extinction throughout all or a significant
portion of its range and is not likely to become so within the
foreseeable future.
DATES: This finding was made on June 28, 2016.
ADDRESSES: The status review report for the smooth hammerhead shark is
available electronically at: http://www.fisheries.noaa.gov/pr/species/fish/smooth-hammerhead-shark.html. You may also receive a copy by
submitting a request to the Office of Protected Resources, NMFS, 1315
East-West Highway, Silver Spring, MD 20910, Attention: Smooth
Hammerhead Shark 12-month Finding.
FOR FURTHER INFORMATION CONTACT: Maggie Miller, NMFS, Office of
Protected Resources, (301) 427-8403.
SUPPLEMENTARY INFORMATION:
Background
On April 27, 2015, we received a petition from Defenders of
Wildlife to list the smooth hammerhead shark (Sphyrna zygaena) as
threatened or endangered under the ESA throughout its entire range, or,
as an alternative, to list any identified Distinct Population Segment
(DPS) as threatened or endangered. The petitioners also requested that
critical habitat be designated for the smooth hammerhead under the ESA.
In the case that the species does not warrant listing under the ESA,
the petition requested that the species be listed based on its
similarity of appearance to the listed DPSs of the scalloped hammerhead
shark (Sphyrna lewini). On August 11, 2015, we published a positive 90-
day finding (80 FR 48053) announcing that the petition presented
substantial scientific or commercial information indicating the
petitioned action of listing the species may be warranted and explained
the basis for that finding. We also announced the initiation of a
status review of the species, as required by Section 4(b)(3)(a) of the
ESA, and requested information to inform the agency's decision on
whether the species warranted listing as endangered or threatened under
the ESA.
Listing Species Under the Endangered Species Act
We are responsible for determining whether smooth hammerhead sharks
are threatened or endangered under the ESA (16 U.S.C. 1531 et seq.). To
make this determination, we first consider whether a group of organisms
constitutes a ``species'' under Section 3 of the ESA, then whether the
status of the species qualifies it for listing as either threatened or
endangered. Section 3 of the ESA defines species to include ``any
subspecies of fish or wildlife or plants, and any distinct population
segment of any species of vertebrate fish or wildlife which interbreeds
when mature.'' On February 7, 1996, NMFS and the U.S. Fish and Wildlife
Service (USFWS; together, the Services) adopted a policy describing
what constitutes a DPS of a taxonomic species (61 FR 4722). The joint
DPS policy identified two elements that must be considered when
identifying a DPS: (1) The discreteness of the population segment in
relation to the remainder of the species (or subspecies) to which it
belongs; and (2) the significance of the population segment to the
remainder of the species (or subspecies) to which it belongs.
Section 3 of the ESA defines an endangered species as ``any species
which is in danger of extinction throughout all or a significant
portion of its range'' and a threatened species as one ``which is
likely to become an endangered species within the foreseeable future
throughout all or a significant portion of its range.'' Thus, in the
context of the ESA, the Services interpret an ``endangered species'' to
be one that is presently at risk of extinction. A ``threatened
species'' is not currently at risk of extinction, but is likely to
become so in the foreseeable future. The key statutory difference
between a threatened and endangered species is the timing of when a
species may be in danger of extinction, either now (endangered) or in
the foreseeable future (threatened).
The statute also requires us to determine whether any species is
endangered or threatened as a result of any one or a combination of the
following five factors: The present or threatened destruction,
modification, or curtailment of its habitat or range; overutilization
for commercial, recreational, scientific, or educational purposes;
disease or predation; the inadequacy of existing regulatory mechanisms;
or other natural or manmade factors affecting its continued existence
(ESA section 4(a)(1)(A)-(E)). Section 4(b)(1)(A) of the ESA requires us
to make listing determinations based solely on the best scientific and
commercial data available after conducting a review of the status of
the species and after taking into account efforts being made by any
State or foreign nation or political subdivision thereof to protect the
species. In evaluating the efficacy of existing domestic protective
efforts, we rely on the Services' joint Policy on Evaluation of
Conservation Efforts When Making Listing Decisions (``PECE''; 68 FR
15100; March 28, 2003) for any conservation efforts that have not been
implemented, or have been implemented but not yet demonstrated
effectiveness.
Status Review
The status review for the smooth hammerhead shark was conducted by
a NMFS biologist in the Office of
[[Page 41935]]
Protected Resources (Miller 2016). The status review examined the
entire species' status throughout its range and also evaluated if any
portion of the smooth hammerhead shark's range was significant as
defined by the Services Significant Portion of its Range (SPR) Policy
(79 FR 37578; July 1, 2014).
In order to complete the status review, information was compiled on
the species' biology, ecology, life history, threats, and status from
information contained in the petition, our files, a comprehensive
literature search, and consultation with experts. We also considered
information submitted by the public in response to our petition
finding. In assessing extinction risk of the smooth hammerhead shark,
we considered the demographic viability factors developed by McElhany
et al. (2000). The approach of considering demographic risk factors to
help frame the consideration of extinction risk has been used in many
of our status reviews, including for Pacific salmonids, Pacific hake,
walleye pollock, Pacific cod, Puget Sound rockfishes, Pacific herring,
scalloped and great hammerhead sharks, and black abalone (see http://www.nmfs.noaa.gov/pr/species/ for links to these reviews). In this
approach, the collective condition of individual populations is
considered at the species level according to four viable population
descriptors: Abundance, growth rate/productivity, spatial structure/
connectivity, and diversity. These viable population descriptors
reflect concepts that are well-founded in conservation biology and that
individually and collectively provide strong indicators of extinction
risk (NMFS 2015b).
The status review report was subjected to independent peer review
as required by the Office of Management and Budget Final Information
Quality Bulletin for Peer Review (M-05-03; December 16, 2004). The
status review report was peer reviewed by three independent specialists
selected from the academic and scientific community, with expertise in
shark biology, conservation and management, and knowledge of smooth
hammerhead sharks. The peer reviewers were asked to evaluate the
adequacy, appropriateness, and application of data used in the status
review, including the extinction risk analysis. All peer reviewer
comments were addressed prior to dissemination of the final status
review report and publication of this determination.
We subsequently reviewed the status review report, its cited
references, and peer review comments, and believe the status review
report, upon which this 12-month finding is based, provides the best
available scientific and commercial information on the smooth
hammerhead shark. Much of the information discussed below on smooth
hammerhead shark biology, distribution, abundance, threats, and
extinction risk is attributable to the status review report. However,
in making the 12-month finding determination, we have independently
applied the statutory provisions of the ESA, including evaluation of
the factors set forth in Section 4(a)(1)(A)-(E) and our regulations
regarding listing determinations. The status review report is available
on our Web site (see ADDRESSES section) and the peer review report is
available at http://www.cio.noaa.gov/services_programs/prplans/PRsummaries.html. Below is a summary of the information from the report
and our analysis of the status of the smooth hammerhead shark. Further
details can be found in Miller (2016).
Description of the Petitioned Species
Taxonomy and Species Description
All hammerhead sharks belong to the family Sphyrnidae and are
classified as ground sharks (Order Carcharhiniformes). Most hammerheads
belong to the Genus Sphyrna with one exception, the winghead shark
(Eusphyra blochii), which is the sole species in the Genus Eusphyra.
The smooth hammerhead was first described in 1758 by Karl Linnaeus and
named Squalus zygaena; however, this name was later changed to the
current scientific species name of Sphyrna zygaena (Linneaus 1758)
(Bester n.d.).
The hammerhead sharks are recognized by their laterally expanded
head that resembles a hammer (hence the common name ``hammerhead''). In
comparison to the other hammerhead sharks, the head of the smooth
hammerhead shark has a scalloped appearance but a rounded un-notched
anterior margin (which helps to distinguish it from scalloped
hammerhead sharks) and depressions opposite each nostril. The smooth
hammerhead also has a ventrally located and strongly arched mouth with
smooth or slightly serrated teeth (Compagno 1984). The body of the
shark is fusiform, lacks a mid-dorsal ridge, and has a moderately tall
and hooked first dorsal fin and a lower second dorsal fin that is
shorter than the notched anal fin (Compagno 1984; Bester n.d.). The
color of the smooth hammerhead shark ranges from a dark olive to
greyish-brown and fades into a white underside, which is different than
most other hammerhead species whose colors are commonly brown (Bester
n.d.).
Range and Habitat Use
The smooth hammerhead shark is a circumglobal species, found
worldwide in temperate to tropical waters between 59 [deg]N. and 55
[deg]S. latitudes (CITES 2013). It is thought to be the hammerhead
species most tolerant of temperate waters (Compagno 1984). In the
northwestern Atlantic Ocean, the range of the smooth hammerhead shark
extends from Nova Scotia, Canada to Florida, and partly into the
Caribbean; however, the species is said to be rare in Canadian waters
and only found offshore in the Gulf Stream (Fisheries and Oceans Canada
2010). Additionally, its presence off the Caribbean Islands cannot be
confirmed, although these waters are noted to be part of its range in
Compagno (1984). In the southwestern Atlantic, the smooth hammerhead
shark range extends from Brazil to southern Argentina, and in the
eastern Atlantic Ocean, smooth hammerhead sharks can be found from the
British Isles to equatorial West Africa and throughout the
Mediterranean Sea (Compagno 1984; Bester n.d).
In the Indian Ocean, the shark is found off the coasts of South
Africa, within the Persian Gulf, along the southern coast of India, Sri
Lanka, and off Indonesia, and along the western and southern coasts of
Australia. Its range in the western and central Pacific extends from
Japan to Vietnam, including the southeast coast of Australia and waters
off New Zealand, the Hawaiian Islands and American Samoa. In the
northeastern Pacific, the smooth hammerhead shark range extends from
northern California to the Nayarit state of Mexico, and in the
southeastern Pacific, the species can be found from Panama to Chile,
but is generally rare in Chilean waters (Brito 2004).
The smooth hammerhead shark is a coastal-pelagic and semi-oceanic
species and generally occurs close inshore and in shallow waters, most
commonly in depths of up to 20 m (CITES 2013). However, the species may
also be found over continental and insular shelves to offshore areas in
depths as great as 200 m (Compagno 1984; Ebert et al. 2013; Bester
n.d.). Smooth hammerhead sharks are highly mobile and may undergo
seasonal migrations (toward cooler waters in the summer and the reverse
in the winter), with juveniles (of up to 1.5 m in length) occasionally
forming large aggregations during these migrations (Compagno 1984;
Diemer et al. 2011; Ebert et al. 2013; Bester n.d.).
[[Page 41936]]
Adult smooth hammerhead sharks, on the other hand, are generally
solitary (Compagno 1984). Based on available tagging data, the species
is able to travel significant distances, with various studies showing
estimates of total distance travelled of around 919 km (Kohler and
Turner 2001), more than 1,609 km (SWFSC 2015), and around 2,220 km
(Clarke et al. 2015).
Diet and Feeding
The smooth hammerhead shark is a high trophic level predator
(trophic level = 4.2; Cort[eacute]s (1999)) and opportunistic feeder
that consumes a variety of teleosts, small sharks (including its own
species), dolphins, skates and stingrays, sea snakes, crustaceans, and
cephalopods (Nair and James 1971; Compagno 1984; Bornatowski et al.
2007; Masunaga et al. 2009; Rogers et al. 2012; Galvan-Magana et al.
2013; Bornatowski et al. 2014; Sucunza et al. 2015). Skates and
stingrays, in particular, tend to comprise the majority of the species'
diet in inshore locations (Nair and James 1971; Bester n.d.), whereas
in coastal and shelf waters, cephalopods appear to be an important prey
item (Bornatowski et al. 2007; Bornatowski et al. 2014).
Growth and Reproduction
The general life history characteristics of the smooth hammerhead
shark are that of a long-lived, slow-growing, and late maturing
species. The average size of a smooth hammerhead shark ranges between
2.5-3.5 m in length, but individuals can reach maximum lengths of 5 m
and weights of 880 pounds (400 kg) (CITES 2013; Bester n.d.). Based on
observed and estimated sizes of smooth hammerhead sharks from both the
Atlantic and Pacific oceans, females appear to reach sexual maturity
between 250 cm and 290 cm total length (TL). Males are considered
sexually mature at smaller sizes than females, with estimates of 210-
250 cm TL from the Atlantic and 250-260 cm TL in the western Pacific.
More recent data from the eastern Pacific (specifically the Gulf of
California) estimate much smaller maturity sizes for smooth hammerhead
sharks, with 50 percent of females and males of the population maturing
at 200 cm and 194 cm TL, respectively (Nava Nava and Fernando Marquez-
Farias 2014). Longevity of the species is unknown but thought to be at
least 20 years (Bester n.d.), with female and male smooth hammerhead
sharks aged up to 18 years and 21 years, respectively, from the eastern
equatorial Atlantic Ocean (Coelho et al. 2011).
The smooth hammerhead shark is viviparous (i.e., give birth to live
young), with a gestation period of 10-11 months (White et al. 2006) and
an assumed annual reproductive periodicity; however this has yet to be
verified (Clarke et al. 2015). Possible pupping grounds and nursery
areas for this species (based on the presence of pregnant females,
neonates, and juveniles) include the Gulf of California, Gulf of
Guinea, Strait of Sicily, coastal and inshore waters off Baja
California, Venezuela, southern Brazil, Uruguay, Morocco, the southern
and eastern cape of South Africa, Kenya (including Ungwana Bay), and
New Zealand (Sadowsky 1965; Castro and Mejuto 1995; Buencuerpo et al.
1998; Arocha et al. 2002; Celona and Maddalena 2005; Costa and Chaves
2006; Bizzarro et al. 2009; Cartamil et al. 2011; Coelho et al. 2011;
Diemer et al. 2011; CITES 2013; Kyalo and Stephen 2013; Bornatowski et
al. 2014; Nava Nava and Fernando Marquez-Farias 2014). Litter sizes
range from around 20 to 50 live pups, with an average of around 33
pups, and length at birth is estimated to be between 49-64 cm. The
smooth hammerhead shark is estimated to grow an average of 25 cm per
year over the first 4 years of its life before slowing down later in
its life (Coelho et al. 2011).
Demography
Although there are very few age/growth studies, based on the best
available data, smooth hammerhead sharks exhibit life-history traits
and population parameters that place the species towards the faster
growing end along the ``fast-slow'' continuum of population parameters
that have been calculated for 38 species of sharks by Cort[eacute]s
(2002, Appendix 2). In an Ecological Risk Assessment study of 20
species caught in Atlantic pelagic fisheries, Cort[eacute]s et al.
(2012) found that the smooth hammerhead shark ranked among the most
productive species (with the 4th highest productivity rate; r = 0.225)
and had one of the lowest vulnerabilities to pelagic longline
fisheries. Based on these estimates, smooth hammerhead sharks can be
characterized as having ``medium'' productivity (based on
categorizations in Musick (1999)), with demographic parameters that
provide the species with moderate resilience to exploitation.
Population Structure
Due to sampling constraints, very few studies have examined the
population structure of the smooth hammerhead shark. Using
mitochondrial DNA (which is maternally inherited) Naylor et al. (2012)
found only a single cluster of smooth hammerhead sharks (in other
words, no evidence to suggest matrilineal genetic partitioning of the
species). This analysis, however, suffered from low sample size, based
on only 16 specimens, but covered the longitudinal distribution of the
species (Naylor et al. 2012). In contrast, Testerman (2014) analyzed
both mitochondrial control region sequences (mtCR; n=303, 1,090 base
pair) and 15 nuclear microsatellite loci (n=332) from smooth hammerhead
sharks collected from 8 regional areas: Western North Atlantic (n=21);
western South Atlantic (n=55); western Indian Ocean (n=63); western
South Pacific (n=44); western North Pacific (n=11); eastern North
Pacific (n=55); eastern Tropical Pacific (n=15); and eastern South
Pacific (n=6). Results from the analysis of mitochondrial DNA indicated
significant genetic partitioning, with no sharing of haplotypes,
between the Atlantic and Indo-Pacific basins (mtCR
[phis]ST=0.8159) (Testerman 2014). Analysis of the nuclear
DNA also showed significant genetic structure between ocean basins
(nuclear FST=0.0495), with the Atlantic and Indo-Pacific
considered to comprise two genetically distinct populations (Testerman
2014). However, additional studies are needed to further refine the
population structure of the smooth hammerhead shark and confirm the
above results, including, as Testerman (2014) suggests, using samples
from individual smooth hammerhead sharks of known size class and
gender.
Species Finding
Based on the best available scientific and commercial information
described above, we determined that Sphyrna zygaena is a taxonomically-
distinct species and, therefore, meets the definition of ``species''
pursuant to section 3 of the ESA. Below, we evaluate whether Sphyrna
zygaena warrants listing under the ESA as an endangered or threatened
species throughout all or a significant portion of its range.
Assessment of Extinction Risk
The ESA (Section 3) defines endangered species as ``any species
which is in danger of extinction throughout all or a significant
portion of its range.'' Threatened species are ``any species which is
likely to become an endangered species within the foreseeable future
throughout all or a significant portion of its range.'' Neither we nor
the USFWS have developed any formal policy guidance about how to
interpret the definitions of threatened and endangered. For the term
``foreseeable future,'' we define it as the timeframe over which
identified threats
[[Page 41937]]
could be reliably predicted to impact the biological status of the
species. For the assessment of extinction risk for smooth hammerhead
sharks, the ``foreseeable future'' was considered to extend out several
decades. Given the species' life history traits, with longevity
estimated to be greater than 20 years, maturity at around 8 years, and
generation time at around 13 years, it would likely take several
decades (i.e., multiple generations) for any recent management actions
to be realized and reflected in population abundance indices (e.g.,
impact of declining shark fin trade). Furthermore, as the main
potential operative threat to the species is overutilization by
commercial and artisanal fisheries (discussed below), this timeframe
(i.e., several decades) would allow for reliable predictions regarding
the impact of current levels of fishery-related mortality on the
biological status of the species. As depicted in the very limited
available catch per unit effort (CPUE) time-series data, trends in the
species' abundance can manifest within this time horizon.
In evaluating the level of risk faced by a species in deciding
whether the species is threatened or endangered, it is important to
consider both the demographic risks facing the species as well as
current and potential threats that may affect the species' status. To
this end, a demographic risk analysis was conducted for the smooth
hammerhead shark and considered alongside the information on threats to
the species, including those related to the factors specified by the
ESA Section 4(a)(1)(A)-(E). Specific methods on the demographic risk
analysis can be found in the status review report, but each demographic
factor was ultimately assigned one of three qualitatively-described
levels of risk: ``very low or low risk,'' ``medium risk,'' or ``high
risk'' (Miller 2016). The information from this demographic risk
analysis in conjunction with the available information on threats
(summarized below) was interpreted using professional judgement to
determine an overall risk of extinction for S. zygaena. Because
species-specific information is insufficient, a reliable, quantitative
model of extinction risk could not be conducted as this time. The
qualitative reference levels of ``low risk,'' ``moderate risk'' and
``high risk'' were used to describe the overall assessment of
extinction risk, with detailed definitions of these risk levels found
in the status review report (Miller 2016).
Evaluation of Demographic Risks
Abundance
Current and accurate abundance estimates are unavailable for the
smooth hammerhead shark. With respect to general trends in population
abundance, multiple studies indicate that smooth hammerhead sharks may
have experienced population declines over the past few decades,
although these studies suffer from very low sample sizes and a lack of
reliable data due to the scarcity of the smooth hammerhead sharks in
the fisheries data. Catch records also generally fail to differentiate
between the Sphyrna species. As such, many of the available studies
examining abundance trends have, instead, looked at the entire
hammerhead shark complex (scalloped, smooth, and great hammerhead
sharks combined). However, attributing the observed declines from these
studies to the smooth hammerhead shark population could be erroneous,
especially given the distribution and proportion of S. zygaena compared
to other hammerhead species. As smooth hammerhead sharks tend to occur
more frequently in temperate waters compared to other Sphyrna species,
they are likely to be impacted by different fisheries, which may
explain the large differences in the proportions that S. zygaena
comprise in the available commercial and artisanal ``hammerhead''
catch. In fact, based on the available information (discussed in more
detail in the section Overutilization for Commercial, Recreational,
Scientific or Educational Purposes), the proportion of smooth
hammerhead sharks compared to the other hammerhead species in the
fisheries data ranges from <1 percent to 100 percent, depending on the
region, location, and timing of the fishing operations. As such, using
other Sphyrna spp. abundance indices estimated from fisheries data to
describe the status of S. zygaena is likely highly inaccurate.
Therefore, we gave greater weight to the available abundance data that
could explicitly or reasonably be attributed to smooth hammerhead
sharks in our evaluation of the level of risk posed by current
abundance.
Unlike the scalloped hammerhead shark, and to a lesser extent, the
great hammerhead shark, NMFS fishery scientists note that there are
hardly any data for smooth hammerhead sharks, particularly in U.S.
Atlantic waters (personal communication J. Carlson). Hayes (2007)
remarks that the species rarely occurs throughout the majority of U.S.
Atlantic waters, and is thought to be less abundant than scalloped or
great hammerhead sharks. Due to these data deficiencies, no official
stock assessment has been conducted (or accepted) by NMFS for the
species in this region. However, two preliminary species-specific stock
assessments of the U.S. Atlantic smooth hammerhead shark population
(Hayes 2007; Jiao et al. 2011) were available for review. These stock
assessments used surplus-production models, which are common for
dealing with data-poor species, and are useful when only catch and
relative abundance data are available (Hayes et al. 2009). Given the
limited amount and low quality of available data on smooth hammerhead
sharks in the U.S. Northwest Atlantic, the only CPUE dataset with
sufficient sample size that could be used as an index of relative
abundance for these stock assessments was the U.S. Pelagic Longline
(PLL) Logbook dataset. Results from the Hayes (2007) stock assessment
estimated a virgin population size of smooth hammerhead sharks to be
anywhere between 51,000 and 71,000 individuals in 1982 and a population
size in 2005 of around 5,200 individuals. While these estimates
translate to a decline of around 91 percent in abundance, based on the
modeled trajectory in the stock assessment (Hayes 2007), abundance
appears to have stabilized in recent years. In fact, the Jiao et al.
(2011) stock assessment model indicated that after 2001, the risk of
overfishing of the species was very low. It is important to note,
though, that the abundance estimates from these stock assessments are
very crude, hampered by significant uncertainty and based on a single
index that may not adequately sample coastal sharks.
Within the Mediterranean region, rough estimates of the declines in
abundance and biomass of smooth hammerhead sharks range from 96 to 99
percent (Celona and Maddalena 2005; Ferretti et al. 2008). Similar to
the previous studies, these findings are hindered by a lack of reliable
data and sufficient sample sizes. Yet, despite the uncertainty in
magnitude of decline, Celona and de Maddalena (2005) provide a detailed
review of historical and recent anecdotal accounts and catch records
from select areas off Sicily that indicate a strong likelihood that
smooth hammerheads have been fished to the point where they are now
extremely rare. Additionally, information from the Mediterranean Large
Elasmobranchs Monitoring (MEDLAM) program, as well as data from more
expansive sampling of Mediterranean fleets operating throughout the
region, also indicate a species that is presently only
[[Page 41938]]
sporadically recorded (Megalofonou et al. 2005; Baino et al. 2012).
Given the extent of the observed decline and evidence of the current
rarity of the species, current abundance levels within this region are
likely placing the species at a high risk of extirpation in the
Mediterranean from anthropogenic perturbations.
In the Indian Ocean, data on trends in smooth hammerhead shark
abundance are available from only two studies conducted in waters off
South Africa. As such, the results are not likely indicative of the
status of the species throughout this region. Furthermore, based on the
findings from the two studies, the trend in the species' abundance
within South African waters is unclear. For example, one study, which
consisted of a 25-year tagging survey (conducted from 1984-2009) off
the eastern coast of South Africa, concluded that the abundance of
smooth hammerhead sharks (based on their availability for tagging)
peaked in 1987 (n=468 tagged) and declined thereafter (Diemer et al.
2011). In contrast, a 25-year time series of annual CPUE of smooth
hammerhead sharks in beach protective nets set off the KwaZulu-Natal
beaches showed no significant trend, with the authors finding no
evidence of a change in the mean or median size of S. zygaena in the
nets over the time period (1978-2003) (Dudley and Simpfendorfer 2006).
Off New South Wales (NSW), Australia, CPUE data from a shark
meshing (bather protection) program was lumped for a hammerhead complex
(scalloped, smooth, and great hammerhead sharks), although the majority
of the hammerhead catch was assumed to comprise S. zygaena given the
species' tolerance of temperate waters (Reid and Krogh 1992; Reid et
al. 2011; Williamson 2011). The data indicate that hammerhead sharks
may have declined by around 85 percent over the past 35 years (Reid et
al. 2011); however, changes in the methods and level of effort of the
program since its inception have complicated these long-term analyses.
Since 2009, annual catches of smooth hammerhead sharks in the nets have
remained fairly stable.
Overall, with only a few regional studies providing limited
information on the present abundance of the smooth hammerhead shark,
the magnitude of declines and the current global abundance of the
smooth hammerhead shark remains unclear. While the species may be at
higher risk of extirpation in the Mediterranean, elsewhere throughout
its range, trends and estimates in abundance do not indicate that the
species' global abundance is so low, or variability so high, that it is
at risk of global extinction due to environmental variation,
anthropogenic perturbations, or depensatory processes, now or in the
foreseeable future. In fact, many of the available regional studies
suggest potentially stable populations. We therefore conclude that, at
this time, the best available information on current abundance and
trends indicates a low demographic risk to the species.
Growth Rate/Productivity
Sharks, in general, have lower reproductive and growth rates
compared to bony fishes; however, smooth hammerhead sharks exhibit
life-history traits and population parameters that place the species
towards the faster growing end along a spectrum of shark species
(Cort[eacute]s 2002, Appendix 2). Cort[eacute]s et al. (2012) found
that the smooth hammerhead shark ranked among the most productive
species when compared to 20 other species of sharks. Based on the
estimate of its intrinsic rate of population increase (r=0.225), smooth
hammerhead sharks can be characterized as having ``medium''
productivity (Musick 1999) with moderate resilience to exploitation.
Given the available information, with no evidence of declining
population trends, it is unlikely that the species' average
productivity is below replacement to the point where the species is at
risk of extinction from low abundance. Additionally, the limited amount
of information on the demography and reproductive traits of the smooth
hammerhead shark throughout its range precludes identification of any
shifts or trends in per capita growth rate. As such, we conclude that,
at this time, the best available information on growth rate/
productivity indicates a low demographic risk to the species.
Spatial Structure/Connectivity
The smooth hammerhead shark range is comprised of open ocean
environments occurring over broad geographic ranges. There is very
little information on specific habitat (or patches) used by smooth
hammerhead sharks. For example, habitat deemed necessary for important
life history functions, such as spawning, breeding, feeding, and growth
to maturity, is currently unknown for this species. Although potential
nursery areas for the species have been identified in portions of its
range, there is no information that these areas are at risk of
destruction or directly impacting the extinction risk of smooth
hammerhead populations.
Although dispersal rates for the species are currently unknown,
there is no reason to believe that they are low within the range of S.
zygaena. While the available data suggest a potentially patchy
distribution for the species, given the relative absence of physical
barriers within their marine environments (compared with terrestrial or
river systems) and the shark's highly migratory nature (with tracking
studies that indicate its ability to move long distances), it is
unlikely that insufficient genetic exchange or an inability to find and
exploit available resource patches are risks to the species. It is also
unknown if there are source-sink dynamics at work that may affect
population growth or species' decline. Thus, there is insufficient
information that would support the conclusion that spatial structure
and connectivity pose significant risks to this species. As such, we
conclude that, at this time, the best available information on spatial
structure/connectivity indicates a very low demographic risk to the
species.
Diversity
There is no evidence that the species is at risk due to a
substantial change or loss of variation in genetic characteristics or
gene flow among populations. Smooth hammerhead sharks are found in a
broad range of habitats and appear to be well-adapted and
opportunistic. There are no restrictions to the species' ability to
disperse and contribute to gene flow throughout its range, nor is there
evidence of a substantial change or loss of variation in life-history
traits, population demography, morphology, behavior, or genetic
characteristics. There is also no information to suggest that natural
processes that cause ecological variation have been significantly
altered to the point where the species is at risk. As such, we conclude
that, at this time, the best available information on diversity
indicates a very low demographic risk to the species.
Summary of Factors Affecting the Smooth Hammerhead Shark
As described above, section 4(a)(1) of the ESA and NMFS
implementing regulations (50 CFR 424.11(c)) state that we must
determine whether a species is endangered or threatened because of any
one or a combination of the following factors: The present or
threatened destruction, modification, or curtailment of its habitat or
range; overutilization for commercial, recreational, scientific, or
educational purposes; disease or predation; inadequacy of existing
regulatory mechanisms; or other natural or man-made factors affecting
its continued
[[Page 41939]]
existence. We evaluated whether and the extent to which each of the
foregoing factors contribute to the overall extinction risk of the
global smooth hammerhead population, with ``significant'' defined as
increasing the risk to such a degree that affects the species'
demographics (i.e., abundance, productivity, spatial structure,
diversity) either to the point where the species is strongly influenced
by stochastic or depensatory processes or is on a trajectory toward
this point. This section briefly summarizes our findings and
conclusions regarding threats to the smooth hammerhead shark and their
impact on the overall extinction risk of the species. More details can
be found in the status review report (Miller 2016).
The Present or Threatened Destruction, Modification, or Curtailment of
Its Habitat or Range
Currently, smooth hammerhead sharks are found worldwide, residing
in temperate to tropical seas. While the exact extent of the species'
global range is not well known, based on the best available data, there
does not appear to be any indication of a curtailment of range due to
habitat destruction or modification. In the Mediterranean (specifically
the Adriatic, Tyrrhenian, Ligurian, and Ionian Seas, Strait of Sicily,
and Spanish Mediterranean waters) the species was previously thought to
be ``functionally extinct'' based on the absence of the species in
records after 1995 (as noted in Ferretti et al. 2008); however, recent
studies provide evidence of the species' continued existence in this
portion of its range, specifically within the Ionian and Tyrrhenian
Seas and Strait of Sicily (Celona and de Maddalena 2005; Sperone et al.
2012). As such, we do not find this to be an indication of a
curtailment of the species' range.
Additionally, there is very little information on habitat
utilization of smooth hammerhead sharks. Because the smooth hammerhead
range is comprised of open ocean environments occurring over broad
geographic ranges, large-scale impacts such as global climate change
that affect ocean temperatures, currents, and potentially food chain
dynamics, may pose a threat to this species. Although studies on the
impacts of climate change specific to smooth hammerhead sharks have not
been conducted, results from a recent vulnerability assessment of
Australia's Great Barrier Reef shark and ray species to climate change
indicate that the closely related great and scalloped hammerhead sharks
have a low overall vulnerability to climate change (Chin et al. 2010).
These findings were, in part, based on the species' low vulnerabilities
to each of the assessed climate change factors (i.e., water and air
temperature, ocean acidification, freshwater input, ocean circulation,
sea level rise, severe weather, light, and ultraviolet (UV) radiation)
(Chin et al. 2010). While this is a very broad analysis of potential
climate change impacts on hammerhead species, no further information
specific to the direct effects of climate change on S. zygaena
populations could be found. Furthermore, given the highly migratory and
opportunistic behavior of the smooth hammerhead shark, these sharks
likely have the ability to shift their range or distribution to remain
in an environment conducive to their physiological and ecological
needs, providing the species with some resilience to the effects of
climate change. Therefore, while climate change has the potential to
pose a threat to sharks in general, including through changes in
currents and ocean circulation and potential impacts to prey species,
there is presently no information to suggest climate change is a
significant threat negatively affecting the status of the smooth
hammerhead shark or its habitat.
Overutilization for Commercial, Recreational, Scientific or Educational
Purposes
In general, there is very little information on the historical
abundance, catch, and trends of smooth hammerhead sharks, with only
occasional mentions in fisheries records. Although more countries and
regional fisheries management organizations (RFMOs) are working towards
improving reporting of species-specific data, catches of hammerhead
sharks have gone and continue to go unrecorded in many countries
outside the United States. Much of the available data on the
exploitation of the smooth hammerhead shark come primarily from
localized study sites and over small periods of time; thus, it is
difficult to extrapolate this information to the global population.
Further complicating the analysis is the fact that data are often
aggregated for the entire hammerhead complex. As stated previously, to
use a hammerhead complex or other hammerhead species as a proxy for
estimates of smooth hammerhead utilization and abundance could be
erroneous, especially given the more temperate distribution and
generally smaller proportion of S. zygaena in the fisheries catch
compared to other hammerhead species. Therefore, more weight is given
to the analyses of the available species-specific fisheries information
compared to hammerhead complex data in determining whether
overutilization is a significant threat to the species.
Smooth hammerhead sharks are both targeted and taken as bycatch in
many global fisheries by a variety of gear types, including: Pelagic
and bottom longlines, handlines, gillnets, purse seines, and pelagic
and bottom trawls. They are valued for their large, high-quality fins
for use in shark fin soup (Abercrombie et al. 2005; Clarke et al.
2006a). Additionally, smooth hammerhead sharks exhibit high mortality
rates after being caught in fishing gear such as longlines and nets. In
fact, estimates of mortality rates range from 47 to 71 percent in
longline fishing gear and 94 to 98 percent in net gear (Cliff and
Dudley 1992; Kotas et al. 2000; Braccini et al. 2012; Coelho et al.
2012; Fernandez-Carvalho et al. 2015). As such, we considered the
impact of historical and current catch and bycatch levels (taking into
account the species' high mortality rate on fishing gear and the
effects of the shark fin trade) on the species' status to evaluate the
threat of overutilization to the species. Due to the lack of global
estimates and the above data limitations, the available information,
including species-specific fishery data, is presented below by regions
to better inform a global analysis.
In the northwestern Atlantic, smooth hammerhead sharks are mainly
caught, albeit rarely, as bycatch in the U.S. Highly Migratory Species
(HMS) commercial longline and net fisheries, and by U.S. recreational
fishermen using rod and reel. Their rare occurrence in the fisheries
data is likely a reflection of the low abundance of the species in this
region (Hayes 2007; NMFS 2015a). As mentioned previously, two
preliminary species-specific stock assessments examined the effect of
U.S. commercial and recreational fishing on the species' abundance in
the northwest Atlantic (Hayes 2007; Jiao et al. 2011). These stock
assessments drew conclusions about the status of the stock (e.g.,
``overfished'' or ``experiencing overfishing'') in relation to the
fishery management terms defined under the Magnuson-Stevens Fishery
Conservation and Management Act (MSA), such as ``maximum sustainable
yield'' (MSY). These statuses, which provide information for
determining the sustainability of a fishery, are based on different
criteria than those under the ESA, which relate directly to the
likelihood of extinction of the species. In other words, the status
under MSA does not necessarily have any relationship to a species'
extinction risk.
[[Page 41940]]
For example, a species could be harvested at levels above MSY but which
do not pose a risk of extinction. As such, the analysis of the results
from these stock assessments were considered in conjunction with
available catch and bycatch trends, abundance, biological information,
and other fisheries data in evaluating whether overutilization is a
threat to the species.
For the stock assessment models, the limited amount and low quality
of available data on smooth hammerhead sharks allowed for the input of
only one index of relative abundance (the U.S. Atlantic PLL dataset)
into the models. Catch time series data for the models included
recreational catches, commercial landings, and pelagic longline
discards. Based on these data, both assessments found significant
catches of smooth hammerhead sharks in the early 1980s. Although these
catches were over two orders of magnitude larger than the smallest
catches, Hayes (2007) suggested that these large catches, which
correspond mostly to the NMFS Marine Recreational Fishery Statistics
Survey (MRFSS), are likely overestimated. Hayes (2007) also identified
other data deficiencies that add to the uncertainty surrounding these
catch estimates, including: Misreporting of the species, particularly
in recreational fisheries, leading to overestimates of catches;
underreporting of commercial catches in early years; and unavailable
discard estimates for the pelagic longline fishery for the period of
1982-1986.
Results from the stock assessments indicated that the northwest
Atlantic smooth hammerhead shark population declined significantly from
virgin levels (by up to 91 percent; Hayes 2007), which was likely a
consequence of fishery-related mortality exacerbated by the species'
vulnerable life history. Although modeled fishing mortality rates were
variable over the years, both assessments found a high degree of
overfishing during the mid-1990s for smooth hammerhead sharks that
likely led to the decline in the population. Towards the end of the
modeled time series, however, Hayes (2007) noted that the stock
assessment was highly sensitive to the inclusion of pelagic discards
for the determination of whether the stock was experiencing overfishing
in 2005. The Jiao et al. (2011) stock assessment model indicated that
after 2001, the risk of overfishing was very low and that the smooth
hammerhead population was still overfished but no longer experiencing
overfishing. Additionally, the modeled trajectory of abundance appears
to depict a depleted but stable population since the early 2000s (Hayes
2007). It is important to note, however, that both studies point out
the high degree of uncertainty associated with these stock assessment
models, with Jiao et al. (2011) warning that the stock assessment model
should be ``viewed as illustrative rather than as conclusive evidence
of their [S. zygaena] present status,'' and Hayes (2007) noting that
the ``Questionable data give us little confidence in the magnitude of
the results.''
Since 2005 (the last year of data included in the stock assessment
models), smooth hammerhead shark catches have remained low, and
additional regulatory and management measures have been implemented
that significantly decrease any remaining risk of overutilization of
the species. For example, in the U.S. bottom longline fishery, which is
the primary commercial gear employed for targeting large coastal
sharks, S. zygaena continues to be a rare occurrence in both the shark
catch and bycatch. Based on data from the NMFS shark bottom longline
observer program, between 2005 and 2014, only 6 smooth hammerhead
sharks were observed caught by bottom longline vessels fishing in the
Gulf of Mexico and South Atlantic (data from 214 observed vessels, 833
trips, and 3,032 hauls; see NMFS Reports available at http://www.sefsc.noaa.gov/labs/panama/ob/bottomlineobserver.htm). In the
pelagic longline fisheries, starting in 2011, the United States
prohibited retaining, transshipping, landing, storing, or selling
hammerhead sharks in the family Sphyrnidae (except for Sphyrna tiburo)
caught in association with International Commission for the
Conservation of Atlantic Tunas (ICCAT) fisheries (consistent with ICCAT
Recommendations 09-07, 10-07, 10-08, and 11-08). During 2012 and 2014,
no smooth hammerhead sharks were reported caught by pelagic longline
vessels, and in 2013, only one was reported caught and subsequently
released alive (NMFS 2013a; NMFS 2014b).
Presently, harvest of the species is managed under the 2006
Consolidated HMS Fishery Management Plan (FMP). With the passage of
Amendment 5a to this FMP, which was finalized on July 3, 2013 (78 FR
40318), management measures have been implemented in the U.S. Federal
Atlantic HMS fisheries that will help decrease fishery-related
mortality of the species. These measures include separating the
commercial hammerhead quotas (which includes great, scalloped, and
smooth hammerhead sharks) from the large coastal shark (LCS) complex
quotas, and linking the Atlantic hammerhead shark quota to the Atlantic
aggregated LCS quotas, and the Gulf of Mexico hammerhead shark quota to
the Gulf of Mexico aggregated LCS quotas. In other words, if either the
aggregated LCS or hammerhead quota is reached, then both the aggregated
LCS and hammerhead management groups will close. These quota linkages
were implemented as an additional conservation benefit for the
hammerhead shark complex due to the concern of hammerhead bycatch and
additional mortality from fishermen targeting other sharks within the
LCS complex. Furthermore, the separation of the hammerhead species from
other sharks within the LCS management unit for quota monitoring
purposes will allow NMFS to better manage the specific utilization of
the hammerhead complex.
Since these management measures have been in place, landings of
hammerhead sharks have decreased significantly. In fact, in 2013, only
49 percent of the Atlantic hammerhead shark quota was reached due to
the closure of the Atlantic aggregated LCS group. In 2014, the Atlantic
LCS quota was reached when only 46 percent of the Atlantic hammerhead
quota had been caught. Most recently, in 2015, only 66 percent of the
Atlantic hammerhead quota was caught. In other words, due to existing
regulatory measures, the mortality of hammerhead sharks from both
targeted fishing and bycatch mortality on fishing gear for other LCS
species appears to have been significantly reduced, with current levels
unlikely to lead to overutilization of the species.
In the southwest Atlantic, hammerhead sharks are susceptible to
being caught by the artisanal, industrial, and recreational fisheries
operating off the coast of Brazil and Uruguay. However, the impact of
these fisheries specifically on smooth hammerhead sharks remains
unclear as the available landings data from this region, which tend to
be lumped for all hammerhead species (Sphyrna spp.), have fluctuated
over the years (Vooren and Klippel 2005). Additionally, when species-
specific fisheries information is available, the data indicate that S.
lewini tend to comprise the majority of the hammerhead shark catch.
According to Vooren and Klippel (2005), the majority of the
hammerhead catch off Brazil is caught by the oceanic drift gillnet
fleet, which operates on the outer shelf and slope between 27 [deg]S.
and 35 [deg]S. latitudes. For example, in 2002,
[[Page 41941]]
total hammerhead landings from all Brazilian fisheries totaled 356 t,
with 92 percent of the landings attributed to the gillnet fleet.
However, similar to the findings from the northwest Atlantic, the
available species-specific fisheries data indicate that smooth
hammerhead sharks comprise a very small proportion of the hammerhead
catch from these fisheries, with estimates of around <1-5 percent
(Sadowsky 1965; Vooren and Klippel 2005).
Although not as frequent as in the oceanic gillnet fisheries,
catches of smooth hammerhead sharks are also observed in the longline
fisheries operating in the shelf and oceanic waters off southern Brazil
and Uruguay. Based on results from a study that examined shark catches
from five S[atilde]o Paulo State surface longliners, smooth hammerhead
sharks may actually comprise a larger proportion of the longline
hammerhead catch in this region (Amorim et al. 2011). Over the course
of 27 fishing trips from 2007-2008, a total of 376 smooth and scalloped
hammerheads were caught, with smooth hammerhead sharks comprising 65
percent of this catch (n=245 S. zygaena). Life stages of 30 male smooth
hammerhead sharks were ascertained, with the large majority (n=20)
constituting juveniles; however, the longliners also caught 10 adults,
primarily during fishing operations in depths of 200 m-3,000 m (Amorim
et al. 2011). In total, hammerhead sharks comprised 6.3 percent of the
shark total by weight, at 37.7 t, which is similar to the range of
yields reported by Silveira (2007) in Amorim et al. (2011), with
estimates from 9 t (in 2002) to 55 t (in 2005).
In the Brazilian artisanal net fisheries, smooth hammerhead sharks
are caught in beach seines, cable nets, and gillnets, which are
deployed off beaches in depths of up to 30 m. Given the area of
operation (e.g., closer to shore, in shallower waters), hammerhead
catches from these artisanal fishing operations consist mainly of
juveniles of both S. lewini and S. zygaena, but generally with higher
proportions of S. lewini. For example, from November 2002 to March
2003, Vooren and Klippel (2005) monitored artisanal fish catches off a
stretch of beach between Chui and Tramandai and recorded a total of 218
hammerhead sharks, with only 4 (or 1.8 percent) identified as smooth
hammerhead sharks. Artisanal fishermen operating near Solitude
Lighthouse (30[deg]42' S) also reported a fish haul of 120 kg of
newborn hammerhead sharks, with around 180 scalloped hammerheads and
only 2 smooth hammerhead sharks (or 1 percent of the hammerhead catch)
(Vooren and Klippel 2005). Off Parana, Bornatowski et al. (2014)
documented 77 juveniles of S. zygaena (with sizes ranging from 67.1-185
cm TL) and 123 scalloped hammerhead sharks in the artisanal gillnet
fish catch over a 2-year period.
Based on the available information, it is clear that all life
stages of the smooth hammerhead shark are susceptible to the fisheries
operating in the southwest Atlantic. However, the degree to which these
fisheries are contributing to overutilization of the species is highly
uncertain. Furthermore, analysis of the available CPUE data from this
region as a reflection of abundance does not indicate any trends that
would suggest the smooth hammerhead shark is at an increased risk of
extinction. The available hammerhead CPUE data (for S. lewini and S.
zygaena combined) from the oceanic gillnet fishery (the fishery that
catches the majority of hammerhead sharks), show a variable trend over
the period of 1992 to 2004. From 1992 to 1997, CPUE decreased from 0.28
(t/trip) to 0.05 (t/trip), and then increased to 0.25 (t/trip) by 2002.
Similarly, there was no discernible trend in the recreational fisheries
CPUE data for hammerhead sharks for the period covering 1999 to 2004
(Vooren and Klippel 2005). The CPUE of the longline fisheries was also
variable, increasing from 0.02 (t/trip) in 1993 to 0.87 (t/trip) in
2000 and then decreasing to 0.02 (t/trip) in 2002 (Vooren and Klippel
2005). However, according to personal communication from the authors
(Vooren and Klippel), cited in Food and Agriculture Organization of the
United Nations (FAO) (2010), the effort data used to estimate CPUE did
not account for changes in the size of gillnets or number of hooks in
the longline fisheries. Given these results, and noting that smooth
hammerhead sharks, while being primarily juveniles, generally tend to
be harvested at low levels, with no evidence of impacts to recruitment,
the available species-specific information does not indicate that
overutilization is a significant threat presently contributing to the
species' risk of extinction in this region.
In the northeast and central Atlantic, smooth hammerhead sharks are
caught primarily by the artisanal and industrial fisheries operating
throughout the region. Additionally, many of these hammerheads are also
juveniles, which could have serious implications on the future
recruitment of hammerhead sharks to the population (Zeeberg et al.
2006; Dia et al. 2012). For example, in a sample of the Spanish
longline fleet landings at the Algeciras fish market (the largest fish
market in southwestern Spain), Buencuerpo et al. (1998) observed that
the average sizes of S. zygaena were 170 cm TL for females and 150 cm
TL for males, indicating a tendency for these fisheries to catch
immature individuals. Similarly, Portuguese longliners targeting
swordfish in the eastern equatorial Atlantic were also observed
catching smooth hammerhead sharks that were smaller than the estimated
sizes at maturity. Between August 2008 and December 2011, Coelho et al.
(2012) reported that the average length for captured smooth hammerheads
(n=372) was 197.5 cm fork length (FL) (220 cm TL) (Coelho et al. 2012),
which falls within the range of maturity size estimates for the
species, but indicates that both adults and immature smooth hammerhead
sharks are being caught. However, the impact of this level of juvenile
catch on the smooth hammerhead shark population is largely unknown due
to a lack of information on S. zygaena population size, CPUE trend
data, or other time-series information that could provide insight into
smooth hammerhead shark recruitment and population dynamics.
Off the west coast of Africa, fisheries data are severely lacking,
particularly species-specific data. While the available information
suggests there has been a significant decline in the overall abundance
of shark species due to heavy exploitation of sharks in the 1990s and
2000s for the international fin trade market, the impact of this past
utilization, and current levels, on the smooth hammerhead shark
population are unclear. There is evidence that hammerhead sharks faced
targeted exploitation by the Senegalese and Gambian fisheries (Diop and
Dossa 2011), but in terms of available hammerhead-specific information
from this region, the data show variable trends in catch or abundance
over the past decade. For example, data from Senegal's annual Marine
Fisheries Reports depict fairly stable landings in recent years, but
with peak highs of around 1,800 mt in 2006 and most recently in 2014
(Republique du Senegal 2000-2014). Seemingly in contrast, in
Mauritanian waters, scientific research survey data collected from
1982-2010 indicate that the abundance of Sphyrna spp. (identified as S.
lewini and S. zygaena) has sharply declined, particularly since 2005,
with virtually no Sphyrna spp. caught in 2010 (Dia et al. 2012).
However, similar to the findings from the other areas in the Atlantic,
scalloped hammerhead sharks appear to be the more common
[[Page 41942]]
hammerhead shark in this region, comprising the majority of the
hammerhead catches and likely influencing the trends observed in the
hammerhead data. For example, in 2009, Dia et al. (2012) reported that
the total catches of sharks in Mauritanian waters amounted to 2,010 mt,
with total hammerhead landings of 221 mt. Smooth hammerheads
constituted only 1.76 percent of the total shark catch (or 35 mt) and
16 percent of the hammerhead total (Dia et al. 2012). Similarly, based
on data from 246 fishery surveys spanning the years from 1962 to 2002
and conducted along the west coast of Africa (from Mauritania to
Guinea, including Cape Verde), scalloped hammerheads occurred more
frequently and in higher numbers in the observed catch. In fact, the
greatest number of smooth hammerhead sharks observed during any single
survey year was 12 individuals, recorded in 1991, whereas the scalloped
hammerhead shark saw a peak of 80 individuals, recorded in 1993 (see
Miller 2016 for more details). Overall, without additional information
on present abundance levels, distribution information, or catch and
overall utilization rates of the smooth hammerhead shark in this
region, conclusions regarding the impact of current fishing pressure
specifically on the extinction risk of the species would be highly
uncertain and speculative.
In the temperate waters of the Mediterranean Sea, smooth hammerhead
sharks have been fished for over a century, and have consequently
suffered significant declines in abundance in this region. In the early
20th century, coastal fisheries would target large sharks and also land
them as incidental bycatch in gill nets, fish traps, and tuna traps
(Feretti et al. 2008). Feretti et al. (2008) hypothesized that certain
species, including S. zygaena, found refuge in offshore pelagic waters
from this intense coastal fishing. However, with the expansion of the
tuna and swordfish longline and drift net fisheries into pelagic waters
in the 1970s, these offshore areas no longer served as protection from
fisheries, and sharks again became regular bycatch. Consequently,
Feretti et al. (2008) estimate that the hammerhead shark abundance in
the Mediterranean Sea (primarily S. zygaena) declined by more than 99
percent over the past 107 years, with the authors considering
hammerhead sharks to be functionally extinct in the region. Although
these specific estimates are highly uncertain, hindered by a lack of
reliable species-specific data and small sample sizes, they indicate a
potentially serious decline in the population of hammerhead sharks
within the Mediterranean that is further confirmed by findings from
Celona and de Maddalena (2005) and fishery surveys conducted throughout
the Mediterranean (Megalofonou et al. 2005; Baino et al. 2012).
Specifically, Celona and de Maddalena (2005) reviewed historical
and more recent data (through 2004) on hammerhead shark (likely S.
zygaena) occurrence from select areas off Sicily and found that smooth
hammerhead sharks have been fished to the point where they are now
extremely rare. Historically, there were no regulations or management
of the hammerhead shark fishery in Italy. When captured, these sharks
were usually retained and sold, fresh and frozen, for human
consumption. In the 1970s, when a specific hammerhead fishery existed
off Sicily, and these sharks were caught in large numbers, their price
even climbed to around 30 percent of swordfish prices (Celona and de
Maddalena 2005). The high value and demand for the species, in
combination with the lack of any regulations to control the fishery,
led to significant overutilization of the species in Sicilian waters.
In the Messina Strait, for example, hammerhead sharks were historically
caught throughout the year and observed in schools, especially when
bullet tuna schools (Auxis rochei rochei) were present in these waters.
Hammerhead sharks were also historically common in waters off Palermo.
Based on data from the most important landing site for the area,
Portciello di Santa Flavia, around 300-400 sharks were caught per year
as bycatch in driftnets targeting swordfish, and around 50 hammerhead
sharks were caught annually in pelagic longlines. However, by the late
1970s, these sharks became noticeably less abundant, with only 1-2
sharks caught per year. Since 1998, no hammerhead sharks have been
observed in the Messina Strait, and the last observed hammerhead shark
in waters off Palermo was caught in 2004 (Celona and de Maddalena
2005). Similar findings were made on the west coast of Sicily, off
Catania, and in waters around Lampedusa Island in the Sicilian Channel,
where hammerhead sharks were once regularly caught by swordfish and
tuna fishermen (in both nets and longlines), but presently are a rare
occurrence. According to Celona and de Maddalena (2005), fishermen
acknowledge the negative effect that the historical heavy fishing
pressure and the extensive use of the drift net gear has had on the
abundance of hammerhead sharks. The authors ``roughly'' estimate that
captures of hammerhead shark have declined by at least 96-98 percent in
the last 30 years as a result of overexploitation.
The disappearance of smooth hammerhead sharks is not just relegated
to waters off Italy. In a sampling of fleets targeting swordfish and
tuna throughout the Mediterranean from 1998 to 2000, only 4 smooth
hammerhead sharks were observed based on data from 5,124 landing sites
and 702 fishing days (onboard commercial fishing vessels) (Megalofonou
et al. 2005). Similarly, the MEDLAM program, which was designed to
monitor the captures and sightings of large cartilaginous fishes
occurring in the Mediterranean Sea, also has very few records of S.
zygaena in its database. Since its inception in 1985, the program has
collected around 1,866 records (including historical records) of more
than 2,000 specimens from 20 participating countries. Out of the 2,048
elasmobranchs documented in the database through 2012, there are
records identifying only 17 individuals of S. zygaena [note: Without
access to the database, the dates of these observations are unknown]
(Baino et al. 2012).
Recently, Sperone et al. (2012) provided evidence of the
contemporary occurrence of the smooth hammerhead shark in Mediterranean
waters, recording 7 individuals over the course of 9 years (from 2000-
2009) near the Calabria region of Italy. Previous findings by Ferretti
et al. (2008) indicated the species was likely extirpated from this
area based on Ionian longline data from 1995 to 1999. Although Sperone
et al. (2012) suggest these new findings may indicate the potential
recovery of smooth hammerhead shark populations in Ionian waters off
Calabria, Italy, the populations in the Mediterranean are still
significantly depleted. Any additional fishing mortality on these
existing populations is likely to significantly contribute to its risk
of extirpation in the Mediterranean. Given the large fishing fleet in
the Mediterranean, this likelihood remains high. In fact, in 2012, the
European Commission (2014) reported a Mediterranean fleet size of
76,023 vessels, with a total fishing capacity of 1,578,015 gross
tonnage and 5,807,827 kilowatt power. As of January 2016, the General
Fisheries Commission for the Mediterranean (GFCM) identified 9,343
large fishing vessels (i.e., larger than 15 meters) as authorized to
fish in the GFCM convention area (which includes Mediterranean waters
and the Black Sea). Of these vessels, 12 percent (or 1,086 vessels)
reported using longlines
[[Page 41943]]
or nets (drift nets, gillnets, trammel nets) as their main fishing gear
(see http://www.gfcmonline.org/data/avl/). While the GFCM passed
Recommendation GFCM/35/2011/7 (C), based on the ICCAT recommendation
10-08, prohibiting the onboard retention, transshipment, landing,
storing, selling, or offering for sale any part or whole carcass of
hammerhead sharks of the family Sphyrnidae (except for the S. tiburo)
taken in the Convention area, as noted previously, the smooth
hammerhead exhibits high rates of at-vessel mortality. Given the
extremely depleted status of the species, it is therefore unlikely that
this regulation will significantly decrease the fishery-related
mortality of the smooth hammerhead shark to the point where it is no
longer at significant risk of further declines and potential
extirpation from overutilization in the Mediterranean.
In the southeastern Atlantic, hammerhead sharks (likely primarily
S. zygaena given the more temperate waters of this region) have also
been reported caught by commercial and artisanal fisheries operating
off Angola, Namibia and the west coast of South Africa. However, within
the Benguela Current Large Marine Ecosystem (defined as west of 20[deg]
E. longitude, north of 35[deg] S. latitude and south of 5[ordm] S.
latitude.) Petersen et al. (2007) found that hammerhead sharks were
only a minor component of the shark bycatch. Based on reported observer
data from the Namibian longline fisheries, hammerhead sharks comprised
only 0.2 percent of the total shark bycatch from 2002-2004, with a very
low catch rate of 0.2 sharks/1000 hooks (Petersen et al. 2007).
Hammerhead sharks were also rarely caught by the South African pelagic
longline fishery, with only one identified hammerhead shark out of
10,435 sharks caught from 2000 to 2005 (Petersen et al. 2007). In the
shark directed longline fishery off South Africa, hammerhead sharks
also appear to comprise a small component of the catch (by number).
Based on logsheet landings data from 1992-2005, as a group,
hammerheads, copper sharks, cowsharks, threshers, and skates made up
only 3 percent of the total number of sharks (Petersen et al. 2007).
Additionally, local demand for smooth hammerhead sharks (particularly
meat) does not appear to be a threat in these waters, with smooth
hammerhead sharks generally relegated to the colloquial ``bad'' trade
category due to the lower value of its flesh in South African markets
(Da Silva and Burgener 2007).
The fisheries information and catch data for the entire Atlantic
region from ICCAT also depict a species that is not regularly caught by
industrial fishing vessels operating throughout the Atlantic Ocean.
ICCAT is the RFMO responsible for the conservation of tunas and tuna-
like species in the Atlantic Ocean and adjacent seas. Smooth hammerhead
sharks are taken in the ICCAT convention area by longlines, purse seine
nets, gillnets, and handlines, with around 44 percent of the total
catch from 1987-2014 caught by drift gillnet gear and 23 percent caught
by longlines. In total, approximately 1,746 mt of smooth hammerhead
catches were reported to ICCAT from 1987-2014.
In 2010, ICCAT adopted recommendation 10-08 prohibiting the
retention onboard, transshipment, landing, storing, selling, or
offering for sale any part or whole carcass of hammerhead sharks of the
family Sphyrnidae (except for S. tiburo) taken in the Convention area
in association with ICCAT fisheries. However, there is an exception for
developing coastal nations for local consumption as long as hammerheads
do not enter into international trade. Despite this exception, analysis
of available observer data from ICCAT fishing vessels shows that, in
general, smooth hammerhead catches are fairly minimal in the industrial
fisheries operating throughout the Atlantic. For example, data from
French and Spanish observer programs, collected over the period of
2003-2007, show that smooth hammerhead sharks represented 3.5 percent
of the shark bycatch (in numbers) in the European purse seine fishery
(Amand[egrave] et al. 2010). This fishery primarily operates in
latitudes between 20[deg] N. and 20[deg] S. and longitudes from 35[deg]
W. to the African coast. In total, only 12 smooth hammerhead sharks
were caught on the 27 observed trips which corresponded to 598 sets
(Amand[egrave] et al. 2010). Similarly, in the tropical Atlantic Ocean,
fishery observers onboard two Chinese tuna longline vessels from
December 2007 to April 2008 (covering 90 fishing days and 226,848
hooks) recorded only 7 smooth hammerhead sharks, making it the second
least commonly encountered shark, with an average CPUE of 0.031 (number
of sharks/1000 hooks) and comprising only 3 percent of the shark
bycatch by weight and 1.1 percent by number (Dai et al. 2009).
Observer data from tuna longliners operating throughout the
Atlantic Ocean also support the observed low likelihood of catching S.
zygaena during normal fishing operations. From 1995-2000, Japanese
observers collected data from 20 trips, covering 886 fishing operations
and 2,026,049 deployed hooks throughout the Atlantic (Matsushita and
Matsunaga 2002). A total of 9,921 sharks were observed; however, only
22 of these were smooth hammerhead sharks, comprising 0.2 percent of
the total shark bycatch (Matsushita and Matsunaga 2002). Observers
aboard Portuguese longline fishing vessels collected more recent data
from 834 longline sets (1,078,200 deployed hooks) and conducted between
August 2008 and December 2011 (Coelho et al. 2012). A total of 36,067
elasmobranchs were recorded over the course of the 3-year study, of
which 372 (or roughly 1 percent) were smooth hammerhead sharks (Coelho
et al. 2012).
Perhaps not surprising, given the above data on ICCAT longline
catches, Cort[eacute]s et al. (2012) conducted an Ecological Risk
Assessment and concluded that smooth hammerheads were one of the least
vulnerable stocks to overfishing by the ICCAT pelagic longline
fisheries. Ecological Risk Assessments are popular modeling tools that
take into account a stock's biological productivity (evaluated based on
life history characteristics) and susceptibility to a fishery
(evaluated based on availability of the species within the fishery's
area of operation, encounterability, post capture mortality and
selectivity of the gear) in order to determine its overall
vulnerability to overexploitation (Cort[eacute]s et al. 2012; Kiszka
2012). Results from the Cort[eacute]s et al. (2012) Ecological Risk
Assessment, which used observer information collected from a number of
ICCAT fleets, indicate that smooth hammerhead sharks face a relatively
low risk in ICCAT fisheries. In fact, based on the best available data
from the Atlantic region, the evidence suggests that while smooth
hammerhead sharks are caught as both targeted catch and bycatch, and
then marketed for both their fins and meat, overall, the present level
of utilization does not appear to be a threat significantly
contributing to the species' risk of extinction.
In the Indian Ocean, smooth hammerhead sharks have historically
been and continue to be caught as bycatch in pelagic longline tuna and
swordfish fisheries and gillnet fisheries, and may also be targeted by
semi-industrial, artisanal and recreational fisheries; however,
fisheries data, particularly species-specific information, are severely
lacking. Presently, there are very few studies that have examined the
status of or collected data specifically on smooth
[[Page 41944]]
hammerhead sharks in the Indian Ocean, making it difficult to determine
the level of exploitation of this species within the ocean basin.
In the western Indian Ocean, where artisanal fisheries are highly
active, studies conducted in waters off Madagascar and Kenya provide
limited data on the catch and use of smooth hammerhead sharks from this
region. For the most part, many of the fisheries operating throughout
this region are poorly monitored, with catches largely undocumented and
underestimated. For example, in southwest Madagascar, McVean et al.
(2006) investigated the directed shark fisheries of two villages over
the course of 10 and 13 months, respectively, and found that the scale
of these fisheries was ``largely unexpected.'' These fisheries,
described as ``traditional fisheries'' (i.e., fishing conducted on foot
or in non-motorized vessels), used both surface-set longlines and also
gillnets to catch sharks. Sharks are processed immediately after
landing, with valuable fins exported to the Far East at high prices and
shark meat sold locally. Out of the examined 1,164 catch records,
hammerhead sharks (Sphyrna spp.; fishermen did not differentiate
between species) were the most commonly caught shark (n = 340),
comprising 29 percent of the total sharks caught and 24 percent of the
total wet weight. Overall, the fisheries landed 123 mt of sharks, which
was significantly higher than the previous annual estimate of 500 kg
per km of Madagascar coastline. The data also provided evidence of
declines in both the numbers of sharks landed and size (McVean et al.
2006). Due to the high economic returns associated with shark fishing
in Madagascar, the authors predicted that these fisheries will likely
continue despite the potential risks of resource depletion. However,
without more accurate species-specific data, the effect of this level
of exploitation, particularly on smooth hammerhead sharks, remains
uncertain. In fact, in other areas of Madagascar, studies examining the
artisanal and shark fisheries, including the genetic testing of fins
from these fisheries, report hammerhead catches that consist mainly of
scalloped hammerhead sharks and, to a lesser degree, great hammerhead
sharks, but no smooth hammerhead sharks (Doukakis et al. 2011; Robinson
and Sauer 2011).
In Kenya, however, there is evidence of smooth hammerhead sharks in
the fish catch. Similar to the McVean et al. (2006) study, Kyalo and
Stephen (2013) analyzed data from various landing sites along the coast
of Kenya as well as observer data from commercial and scientific trawl
surveys to examine the extent of shark catch in Kenya's artisanal tuna
fisheries and semi-industrial prawn trawls. In Kenya, sharks are
primarily caught as bycatch, with the meat consumed locally and fins
exported to Far East countries (including Hong Kong and China). Based
on data collected over a 1-year period (July 2012-July 2013),
hammerhead sharks (S. lewini and S. zygaena) comprised 58.3 percent of
the shark catch in the semi-industrial prawn trawl fisheries. Smooth
hammerhead sharks, alone, made up 27 percent of the sharks (n=69), with
a catch rate estimated at 2 kg/hour. Additionally, all of the smooth
hammerheads were neonates, with the vast majority within the estimated
size at birth range, indicating that the fishing grounds likely also
serve as parturition and nursery grounds for the species. While it is
particularly concerning that the Kenyan semi-industrial trawl fisheries
are harvesting neonate and juvenile smooth hammerhead sharks, the
degree to which this harvest is impacting recruitment of S. zygaena to
the population is unknown. However, the authors do note that the
general catch trend of elasmobranchs in Kenya has exhibited a declining
trend since 1984, and suggest additional research is needed to
determine current harvest rates and sustainable catch and effort
levels.
While range maps place smooth hammerhead sharks within the Persian
Gulf, there is no available information on the abundance or magnitude
of catches of S. zygaena within this body of water. In the waters of
the United Arab Emirates (UAE), hammerhead sharks are noted as
generally ``common'' and are currently protected from being retained or
landed. However, while the UAE prohibits the export of hammerheads
caught in UAE waters, it still allows for the re-export of these sharks
caught elsewhere (such as in Oman, Yemen, and Somalia) (Todorova 2014).
In fact, in the past decade, the UAE has emerged as an important
regional export hub for these countries in terms of the international
shark fin trade, exporting up to 500 mt of dried raw fins annually to
Hong Kong. Yet, information on the species traded and quantities
involved is limited. Based on data collected from 2010-2012 at the
Deira fish market (the only auction site in UAE for sharks destined for
international trade), hammerheads were the second most represented
family in the trade (at 9.3 percent) behind Carcharinidae sharks (which
represented 74.9 percent of the species) (Jabado et al. 2015). A total
of 12,069 sharks were recorded at the fish market, with the majority
originating from Oman (Jabado et al. 2015). Around half (6,751
individuals) were identified to species, with 186 identified as S.
zygaena caught in Oman waters (Jabado et al. 2015). Thus, while the UAE
affords protections to hammerhead sharks within its own waters, its re-
export business continues to drive the demand for the species
throughout the region. However, while UAE traders confirmed that fins
from hammerhead sharks are highly valued, they also note that the
general trend in recent years has been a decline in prices and profits
due to a reduction in demand for fins in Hong Kong (see Shark Fin Trade
section for more details) (Jabado et al. 2015). As such, this decrease
in demand may translate to a decrease in fishing pressure on the
species. Yet, without any data on catch trends, fishing effort, or the
size of the S. zygaena population in this region, the impact of current
or even future fishing mortality rates on the smooth hammerhead
population remains unknown.
In the central Indian Ocean, data on smooth hammerhead shark
utilization is available from the countries of Sri Lanka, India, and
Indonesia. In Sri Lanka, shark meat, both fresh and dried, is used for
human consumption as well as for a cheap animal feed source, while
shark fins are exported to other countries (SL-NPOA-Sharks 2013). Shark
catches in Sri Lanka reached high levels in the 1980s, coinciding with
demand for shark products in the international market, and peaked in
1999 at 34,842 mt (SL-NPOA-Sharks 2013). However, since 1999, annual
shark catches have exhibited a significant decline, down to a low of
1,611 t in 2014 (Jayathilaka and Maldeniya 2015). According to
Jayathilaka and Maldeniya (2015), the decline in annual shark
production, particularly over the past few years, can be mainly
attributed to the implementation and enforcement of new regulations on
sharks and, specifically, conservation provisions for thresher sharks
(which were one of the more dominant species in the shark catches). The
authors further go on to state that the declining price of shark fins
has also influenced fishermen to shift to export-oriented tuna
fisheries. In terms of the impacts on smooth hammerhead sharks, when
the data are broken out by shark species, hammerhead sharks have and
continue to comprise a very small proportion of the catch. Based on
landings data over the past decade (and similarly reported
[[Page 41945]]
in historical catches), silky sharks tend to dominate the shark catch,
followed by blue sharks, thresher sharks (until their prohibition in
2012), and oceanic whitetip sharks. In 2014, smooth hammerhead sharks
comprised around only 1 percent of the retained shark bycatch in Sri
Lanka, with a total of 18 mt caught (Hewapathirana et al. 2015;
Jayathilaka and Maldeniya 2015). While sharks have generally declined
in Sri Lankan waters due to historical overutilization, there is no
information to indicate that present catch levels of S. zygaena are a
significant threat to the species in this portion of its range.
Similarly, in Indian waters, available longline survey data
collected from within the exclusive economic zone (EEZ) show that
smooth hammerheads tend to comprise a small portion of the shark
bycatch (0.5-5 percent) (Varghese et al. 2007; John and Varghese 2009).
Although India is considered to be one of the top shark-fishing
nations, smooth hammerhead sharks, in particular, are not considered to
be a species of interest (based on 2008-2013 Indian Ocean Tuna
Commission (IOTC) data holdings) (Clarke and IOTC Secretariat 2014).
The same appears true for Indonesia, which is considered to be the
largest shark-catching country in the world. In fact, the available
landings and observer data suggest that S. zygaena distribution is not
likely concentrated within Indonesian fishing areas. For example, in an
analysis of data collected from Indonesian tuna longline fishing
vessels from 2005-2013, scientific observers recorded only 6 smooth
hammerheads (covering 94 trips, 2,268 operations, and 3,264,588 hooks)
(Novianto et al. 2014). In another study, data were collected and
analyzed from numerous fish markets and landing sites throughout
Indonesia from 2001-2005, including Central Java, Bali, Jakarta, West
Java, and Lombok. This study revealed that Sphryna spp. are among the
most commonly taken shark species as bycatch; however, when identified
to species, only S. lewini was detected within the landings data
(Blaber et al. 2009). Similarly, a study that used DNA barcoding to
identify shark fins from numerous traditional fish markets and shark-
fin exporters across Indonesia (from mid-2012 to mid-2014) found a
relatively high frequency of scalloped hammerhead sharks in the data
(10.48 percent of fins; 2nd most common shark), whereas S. zygaena,
while present in the fish markets, comprised only 1.03 percent of the
fins (n=6 fins) (Sembiring et al. 2015). These results are not that
surprising given the more temperate distribution of the smooth
hammerhead shark compared to the tropical scalloped hammerhead.
However, it also speaks to the threat of overutilization in that the
largest shark-catching country in the world appears to primarily target
sharks in tropical waters, so smooth hammerhead sharks may be provided
some protection from these intensive fisheries due to their more
temperate distribution.
Given the above information on distribution, it is not surprising
that the majority of S. zygaena catches in Australian waters is
attributed to the Western Australian temperate gillnet and longline
fisheries, which operate in continental shelf waters along the southern
and lower west coasts. The main commercial shark species targeted in
these fisheries are gummy sharks (Mustelus antarcticus), dusky sharks
(Carcharhinus obscurus), whiskery sharks (Furgaleus macki) and sandbar
sharks (Carcharhinus plumbeus). Smooth hammerhead sharks are considered
to be a bycatch species and tend to comprise over 98 percent of the
hammerhead catch from this fishery (Australian Government 2014;
Commonwealth of Australia 2015). A recent multi-fisheries bycatch
assessment, which examined the sustainability of bycatch species in
multiple Gascoyne and West Coast Australian fisheries, found smooth
hammerhead sharks to be at a low to moderate risk in this region, with
the risk largely influenced by the species' biological profiles
(vulnerable life history traits) as opposed to fishery impacts (Evans
and Molony 2010). Between 1994 and 1999, McAuley and Simpfendorfer
(2003) estimated that the average annual take of smooth hammerheads in
the Western Australian temperate gillnet and longline fisheries was
around 53 t. Based on recent catches of hammerhead sharks (range: 59.9
t-71 t), harvest levels have increased slightly since the 1990s, but
have remained fairly stable over the past 4 years. Furthermore, these
harvest levels are considered to be within the recommended sustainable
take for the species, which has been estimated at around 70 t per year
(Australian Government 2014). An increasing CPUE trend specifically for
hammerhead sharks in this fishery (Simpfendorfer 2014), as well as a
declining trend in total gillnet effort (with effort on the west coast
now at low historical levels) (Government of Western Australia 2015),
suggests that the ongoing harvest of the species by the Western
Australian temperate gillnet fisheries is unlikely to be a significant
threat to the species.
Fisheries information and catch data from the RFMO that operates
throughout the Indian Ocean (the IOTC) also depict a species that is
not regularly caught by industrial fishing vessels (see Miller (2016)
for more details), nor does this RFMO consider the species to be a key
``priority species'' (i.e., those shark species whose status the IOTC
is concerned about and have scheduled future stock assessments). While
current catches reported in the IOTC public domain database are thought
to be incomplete and largely underestimated (Murua et al. 2013; IOTC
2015), the available observer data from the IOTC convention area
suggest that smooth hammerhead sharks tend to be rare in the various
industrial and artisanal fisheries operating within the convention area
(Huang and Liu 2010).
In the western Pacific, smooth hammerhead sharks are regularly
recorded in fisheries catch data, particularly from the temperate
waters off southeastern Australia and New Zealand. They have also been
reported in landings data from Japan, as far north as Hokkaido
(Taniuchi 1974). According to Taniuchi (1974), smooth hammerhead sharks
were historically widely distributed throughout Japan, with their flesh
sold at fish markets from Shikoku to the Kanto District and Hokkaido;
however, species-specific data are lacking. Over the past decade,
reported catches of hammerhead sharks at main fishing ports in Japan
have been low and variable (range: <10 mt to <40 mt), with no clear
trend (Fisheries Agency of Japan 2015). Furthermore, overall fishing
effort by Japanese longliners (which are responsible for the majority
of shark catches) has been on a declining trend since the late 1980s,
with significant declines noted particularly in the Pacific Ocean
(Fisheries Agency of Japan 2011; Uosaki et al. 2015), with expansion of
the scale of these fisheries unlikely in the foreseeable future
(Fisheries Agency of Japan 2011).
Although Japan is a significant producer and exporter of sharks
fins, ranking 10th worldwide in terms of chondrichthyan catches and
11th in (dried) shark fin exports from 2000-2011, both capture
production and fin exports have steadily declined over the past decade
(Dent and Clarke 2015). Compared to statistics from 2000, Japan's
catches of chondrichthyans decreased by 68 percent in 2011 and fin
exports dropped by 52 percent in 2012. Additionally, Japan has stated
that due to the uncertainty of the stock structure of hammerhead
sharks, as well as the lumping of all hammerhead sharks in the
available Japanese data, it is unable to make a CITES non-detriment
finding for the export of hammerhead shark
[[Page 41946]]
species (Fisheries Agency of Japan 2015). Effective September 14, 2014,
scalloped, smooth, and great hammerhead sharks are listed on Appendix
II of the Convention on International Trade in Endangered Species of
Wild Fauna and Flora (CITES), which means that international trade in
specimens of these species may be authorized by the granting of a CITES
export permit or re-export certificate. However, under CITES, these
permits or certificates should only be granted if that trade will not
be detrimental to the survival of the species. This is done through the
development of a ``non-detriment'' finding, or NDF. Because Japan is
unable to make an NDF for the export of scalloped, smooth, or great
hammerhead sharks, it will not issue any permits for the export of
products from these species. This decision has likely significantly
decreased the incentive for Japanese fishermen to target smooth
hammerhead sharks for the international fin trade market, and has
decreased the threat of overutilization of the species within Japanese
waters.
Smooth hammerhead sharks are also documented in the fisheries catch
data from Taiwan, whose fleet also ranks in the top ten for global
shark catches. However, based on the available data, the species does
not appear to be a significant component of the shark catch. For
example, from 2002-2010, Liu and Tsai (2011) examined offloaded
landings at two major fish markets in Taiwan (Nanfangao and Chengkung)
to get a better sense of the catch composition and whole weight of the
sharks commonly caught by Taiwanese offshore tuna longliners. What they
found was that there are 11 species of pelagic sharks that are commonly
caught by the longliners, with blue sharks dominating the shark
landings (by weight), comprising an average of 44.5 percent of the
landings, followed by scalloped hammerheads (at 9.87 percent) and
shortfin makos (at 9.42 percent) (Liu and Tsai 2011). Smooth hammerhead
sharks, on the other hand, were one of the least represented species,
comprising an average of 1.38 percent of the landings over the study
period, which translated to around 78 mt per year (Liu and Tsai 2011).
Since 2010, reported annual catches of smooth hammerhead sharks by
Taiwan's tuna longline fleets have ranged from 81 mt to 149 mt
(Fisheries Agency of Chinese Taipei 2015).
According to the annual reports of Chinese Taipei, provided to the
Western and Central Pacific Fishery Commission (WCPFC), over 93 percent
of the smooth hammerhead bycatch can be attributed to the small scale
tuna longline vessels, which operate mostly in the EEZ of Taiwan but
also beyond the EEZ (particularly those vessels with freezing equipment
which allows for expansion to more distant waters). Since 2011,
reported smooth hammerhead shark catches by both the large and small-
scale longline fleets have decreased, but so has fishing effort, with a
decline in the number of active vessels engaged in the fisheries
(Fisheries Agency of Chinese Taipei 2015). Presently, there is no
information to indicate overutilization of S. zygaena in Chinese Taipei
by these fisheries.
Off the east coast of Australia, smooth hammerhead sharks are
normally found in continental shelf waters. While the majority of
smooth hammerhead shark catches are taken in the previously discussed
Western Australian fisheries, minimal numbers are also caught in the
Commonwealth-managed southern shark fishery and the NSW Offshore Trap
and Line Fishery, which operates off the eastern and southern coasts of
Australia (Macbeth et al. 2009; Simpfendorfer 2014). Hammerhead sharks
are also occasionally caught in Australia's NSW Shark Meshing Program
(SMP). The NSW SMP annually deploys a series of bottom-set mesh nets
between September 1st and April 30th along 51 ocean beaches from
Wollongong to Newcastle. Based on the data from the NSW SMP, the CPUE
of hammerhead sharks (likely S. zygaena, given the placement of nets in
more temperate waters; Reid et al. 2011; Williamson 2011) over the past
decade has exhibited a declining trend, although no significant trend
was found when data from the start of the program were included (from
1950-2010; Reid et al. 2011). Yet, since the 1970s, the number of
hammerhead sharks caught per year in the NSW beach nets has decreased
by more than 90 percent, from over 300 individuals in 1973 to fewer
than 30 in 2008 (Williamson 2011).
While changes in the SMP methods and level of effort since its
inception have complicated long-term analyses, in 2005, the SMP was
listed as a ``key threatening process'' by the NSW Fisheries Scientific
Committee (convened under Australia's Fisheries Management Act 1994)
and the NSW Scientific Committee (convened under Australia's Threatened
Species Conservation Act 1995). It was listed as such due to its
adverse effect on threatened species, populations, or ecological
communities, and its potential for causing species, populations, or
ecological communities that are not yet threatened to become
threatened. Since 2009, the program has operated in accordance with
Joint Management Agreements and an associated management plan, with an
objective of minimizing the impact of its nets on non-target species
(such as smooth hammerhead sharks) and threatened species to ensure
that the SMP does not jeopardize the survival or conservation status of
the species. To meet this objective, the SMP developed a ``trigger
point'' that, when tripped, indicates additional measures are needed to
comply with the objective. The trigger point is defined as:
``entanglements of non-target species and threatened species over two
consecutive meshing seasons exceed twice the annual average catch of
the preceding 10 years for those species.'' For smooth hammerhead
sharks, the trigger point was estimated at 55 individuals. Based on
recent species-specific data from the SMP program, the annual catch of
smooth hammerhead sharks has remained below the trigger point for the
past 5 years, ranging from 18 sharks captured in 2010 to 42 sharks in
2014, indicating that under the current evaluation parameters, the SMP
is not considered to be impacting S. zygaena to the extent that it
would jeopardize its survival or conservation status (NSW Department of
Primary Industries 2015).
To the east, in New Zealand, smooth hammerhead sharks are
occasionally caught as bycatch in commercial fisheries, but are
prohibited from being targeted. The available data from New Zealand
waters, covering the time period from 1986-1997, show no clear trend in
smooth hammerhead landings (Francis and Shallard 1998), and
corresponding effort information is unavailable. When compared to all
shark landings for the same time period, smooth hammerhead sharks
comprised <1 percent of the total, indicating that the commercial
fisheries in this region likely do not pose a significant threat to the
species. However, in an analysis of 195 shark fillets from marketed
cartons labelled as lemon fish (Mustelus lenticulatus), 14 percent were
identified as S. zygaena (n=28). Similarly, analysis of 392 shark fins
obtained from commercial shark fisheries operating in the Bay of Plenty
indicated that 12 percent (n=47) came from smooth hammerhead sharks.
These data suggest that while smooth hammerhead sharks may be
prohibited from being targeted in New Zealand waters, they are still
occasionally landed. However, at present, there is no indication that
the impact of this take on the population is
[[Page 41947]]
significantly contributing to the species' risk of extinction in this
region.
In the central Pacific, smooth hammerhead sharks are caught as
bycatch in the Hawaii and American Samoa pelagic longline fisheries.
NMFS authorizes these pelagic longline fisheries under the Fishery
Ecosystem Plan for Pelagic Fisheries of the Western Pacific (Pelagics
FEP) developed by the Western Pacific Fishery Management Council
(WPFMC) and approved by NMFS under the authority of the MSA. The WPFMC
has implemented strict management controls for these fisheries.
Although smooth hammerhead sharks are not a target species in these
pelagic longline fisheries, the measures that regulate the longline
fishery operations have helped to monitor the bycatch of smooth
hammerhead sharks and may minimize impacts to the species. Some of
these regulations include mandatory observers, vessel monitoring
systems, designated longline buffer zones, areas of prohibited fishing,
and periodic closures and effort limits (see Miller et al. (2014a) for
more details). A mandatory observer program for the Hawaii-based
pelagic longline fishery was also initiated in 1994, with coverage rate
that increased to a minimum of 20 percent in 2001. The Hawaii-based
deep-set pelagic longline fishery is currently observed at a minimum of
20 percent and the Hawaii-based shallow-set pelagic fishery has 100
percent observer coverage. The American Samoa longline fishery has also
had an observer program since 2006, with coverage ranging between 20
percent and 33 percent since 2010.
Based on the available observer data, smooth hammerhead sharks
appear to be caught in low numbers and comprise a very small proportion
of the bycatch. For example, from 1995-2006, only 49 S. zygaena
individuals on 26,507 sets total were observed caught for both Hawaii-
based pelagic longline fishery sectors combined, translating to an
estimated nominal CPUE of 0.001 fish per 1,000 hooks (Walsh et al.
2009). Additionally, according to the U.S. National Bycatch Report
(NMFS 2011; NMFS 2013b), the Hawaii-based deep-set pelagic longline
fishery reported only 2,453.74 pounds (1.1 mt) of smooth hammerheads as
bycatch in 2005 and 3,173.91 pounds (1.44 mt) in 2010. The Hawaii based
shallow-set pelagic longline fishery reported even lower levels of
bycatch, with 930.35 pounds (0.422 mt) in 2005 and no bycatch of smooth
hammerhead sharks in 2010. From 2010 to 2013, only three smooth
hammerheads were observed caught in the American Samoa longline
fishery, all in 2011, with total take extrapolated to 12 individuals
(NMFS Pacific Islands Fisheries Science Center (PIFSC), unpublished
data). The number of unidentified hammerhead sharks observed caught for
the same period was 2, extrapolated to 11 total (PIFSC, unpublished
data). Given the strict management of these pelagic longline fisheries
and the low levels of bycatch, with no evidence of population declines
of smooth hammerhead sharks in this area, there is no information to
suggest that overutilization is presently a threat in this portion of
the species' range.
The WCPFC, the RFMO that seeks the conservation and sustainable use
of highly migratory fish stocks throughout the western and central
Pacific Ocean, has also collected data on the longline and purse seine
fisheries operating throughout the region; however, data specific to
smooth hammerhead sharks (and hammerhead sharks in general) is severely
limited. Only since 2011 have WCPFC vessels been required to report
specific catch information for hammerhead sharks (in their annual
reports to the WCPFC), and it tends to be for the entire hammerhead
group (including S. mokarran, S. lewini,S. zygaena, and Eusphyra
blochii). Given the lumping of all hammerhead species together and the
limited information on catches and discards, the available data provide
little insight into the impact of present utilization levels on the
status of smooth hammerhead shark in this region (see Miller (2016) for
more details).
Similarly, available WCPFC observer data are also lacking, hindered
by low observer rates and spatio-temporal coverage of fishing effort
throughout the region. This is particularly true in the longline
fisheries where coverage rates have been below 2 percent since 2009,
despite the requirement under the Conservation and Management Measure
for the Regional Observer Programme (CMM 2007[hyphen]01) requiring 5
percent observer coverage by June 2012 in each longline fishery (Clarke
2013). With these limitations in mind, the available observer data from
1994-2009 indicate that, in general, catches of hammerhead sharks (S.
mokarran, S. lewini, S. zygaena, and E. blochii) are negligible in all
WCPFC fisheries. Rice et al. (2015) analyzed the WCPFC observer data
through 2014 and found that hammerhead sharks generally have low
encounter rates (i.e., low frequency of occurrence in the western and
central Pacific Ocean). In the purse-seine fisheries data, Rice et al.
(2015) noted that observations of hammerhead sharks are ``virtually
non-existent,'' and in the longline observer data, hammerheads had a
patchy distribution (concentrated around the Hawaiian Islands, Papua
New Guinea, and Australian east coast), but relatively stable CPUE
(from 2002-2013). However, due to the overall low frequency of
occurrence of the species in the data, no conclusions could be made
regarding hammerhead shark temporal trends, with Rice et al. (2015)
noting that a stock assessment to determine the status of the
hammerhead shark species throughout the western and central Pacific
Ocean would not be feasible at this time.
In the eastern Pacific Ocean, smooth hammerhead sharks are both
targeted and taken as bycatch in industrial and artisanal fisheries.
While the range of the smooth hammerhead shark is noted as extending as
far north as northern California waters, based on the available data,
the distribution of the species appears to be concentrated in waters
off Mexico and areas south (Miller 2016). Observer data of the west
coast based U.S. fisheries further confirms this finding, with smooth
hammerhead sharks rarely observed in the catches (Miller 2016). In
Mexico, however, sharks, including hammerheads, are considered an
important component of the artisanal fishery (Instituto Nacional de la
Pesca 2006), and artisanal fisheries account for around 80 percent of
the elasmobranch fishing activity (Cartamil et al. 2011). Sharks are
targeted both for their fins, which are harvested by fishermen for
export, and for their meat, which is becoming increasingly important
for domestic consumption. Yet, details regarding fishing effort and
species composition of artisanal landings are generally unavailable
(Cartamil et al. 2011).
Information on Mexican artisanal catches specifically of smooth
hammerhead sharks was found in studies examining artisanal fishing
camps operating off Sinaloa, the ``Tres Marias'' Islands of Mexico, and
Laguna Manuel (P[eacute]rez-Jim[eacute]nez et al. 2005; Bizzarro et al.
2009; Cartamil et al. 2011). While findings from these studies indicate
a predominance of immature smooth hammerhead sharks in artisanal
landings, the CPUE is low, with S. zygaena representing a fairly small
component of the shark and hammerhead catch. For example, a 1999 survey
of the Sinaloa artisanal elasmobranch-targeted fishery revealed that
CPUE (# individuals/vessel/trip) of smooth hammerhead sharks ranged
from 0 to 0.7, depending on the season (Bizzarro et al. 2009). From
2006-2008, a study of the Laguna Manuela artisanal fishing camp,
identified as one of the most important elasmobranch fishing camps in
Baja California, found that out of 10,595 captured elasmobranchs over
[[Page 41948]]
the course of 387 panta trips (small-scale operations, using 5-8 m long
boats), only 306 (~3 percent) were smooth hammerhead sharks. The
estimated CPUE was 1.32 (mean catch per trip) on gillnet and 0.08 on
longline (Cartamil et al. 2011). Carcass discard sites were also
surveyed outside of the Laguna Manuela fishing camp, with species
composition within the sites very similar to the beach survey catch.
Within the 17 carcass discard sites, 31,860 elasmobranch carcasses were
identified, with 374 attributed to smooth hammerhead sharks (1.17
percent) (Cartamil et al. 2011).
In July 2015, the CITES Scientific Authority of Mexico held a
workshop in an effort to collect information and assess the
vulnerability of CITES-listed shark species to harvesting pressures in
fishing grounds throughout all Mexican waters. Participants from
government agencies, academic institutions, civil associations and
independent consultants with experience on the management and knowledge
of shark fisheries in all fishing areas and coasts of Mexico gathered
to discuss the available data and conduct Productivity and
Susceptibility Assessments for each shark species (following methods
proposed by Patrick et al. 2010; Ben[iacute]tez et al. (2015)). For S.
zygaena, the semi-quantitative assessment looked at the species'
vulnerability in specific fishing zones along the Pacific coast and
also by fishing vessel type (small or coastal vessels versus large
fishing vessels). Results from the assessment showed that S. zygaena
had a medium to low vulnerability to fishing pressure by large Mexican
fishing vessels for all evaluated fishing zones, and a higher
vulnerability to fishing by smaller/coastal vessels, particularly off
the Pacific coast of Baja California south to Jalisco (Ben[iacute]tez
et al. 2015). While these assessments provide managers and scientists
with an index of the vulnerability of target and non-target species to
overfishing within a fishery (e.g., S. zygaena is more likely to
experience overfishing by smaller/coastal vessels as opposed to the
larger fishing vessels), it does not provide information on the current
status of the species or whether the species, is, in fact, being
overfished in waters off Mexico.
While the best available information, including from the above
assessment and the fisheries surveys, shows that smooth hammerhead
sharks (and particularly juveniles) are being utilized and face higher
fishing pressure in the Mexican artisanal fisheries, without any
information on current population size or CPUE trends in this region,
the impact of this level of utilization on the extinction risk of the
species is presently unknown. Due to the limited data available, the
status of the Mexican S. zygaena population remains highly uncertain,
with no data to indicate that overutilization is a threat significantly
contributing to the species' risk of extinction.
In waters farther south in the Eastern Pacific, three countries
(Costa Rica, Ecuador and Peru) contribute significantly to shark
landings and are important suppliers of shark fins for the Asian
market. In Costa Rica, where shark fishing is still allowed, the
limited available fisheries data suggest that smooth hammerhead sharks
are only rarely caught as catch and bycatch (Whoriskey et al. 2011;
Dapp et al. 2013). However, recent data on fin exports indicate that
the species, at least when caught, is kept and utilized for the
international fin trade market. For example, in December 2014, around
259.2 kg of S. zygaena fins and 152 kg of S. lewini fins were exported
out of Costa Rica to Hong Kong (Boddiger 2015). In February 2015, Costa
Rican officials allowed the export of another batch of scalloped and
smooth hammerhead fins, with estimates of total weight between 249-490
kg (depending on the source of information) (Boddiger 2015). The
conservation group Sea Turtle Recovery Programme estimated that these
fins came from between 1,500 and 2,000 hammerhead sharks (Boddiger
2015). While the impact of this take on the smooth hammerhead
population is highly uncertain, given the lack of species-specific
abundance estimates or trends for this region, in March 2015, the
National System of Conservation Areas, in its role as the CITES
Administrative Authority of Costa Rica, stated that no more export
permits for hammerhead fins would be issued until the CITES NDF process
is completed (Murias 2015). Whether this moratorium on exports will
curb fishing of hammerhead sharks and decrease fishery mortality rates
for the species has yet to be seen. In addition, depending on the
findings from the NDF process, some level of export of hammerhead
products may still be allowed in the future. Nevertheless, without
information on the size or distribution of the smooth hammerhead
population in this region, or evidence of declines in abundance, the
best available information does not presently suggest that current
levels of fishery-related mortality are significantly contributing to
the overutilization of S. zygaena.
In Ecuador, directed fishing for sharks is prohibited, but sharks
can be landed if caught as bycatch. Hammerhead sharks, in particular,
tend to be landed as incidental catch and, similar to Costa Rica, are
used primarily for the fin trade. Unlike many of the other areas
discussed in this report, smooth hammerhead sharks appear to be the
dominant hammerhead species caught in Ecuadorian waters. Based on
artisanal records from 2007-2011, catches of S. zygaena are on the
order of three to four times greater than catches of S. lewini (see
Miller 2016). Additionally, the majority of the smooth hammerhead
sharks taken in Ecuadorian fisheries appear to be immature (Aguilar et
al. 2007; Cabanilla and Fierro 2010), which, as mentioned previously,
could potentially negatively affect recruitment and contribute to
declines in the abundance of smooth hammerhead sharks. However, without
information on corresponding fishing effort or population sizes,
inferences regarding the status of the species or the impacts of
current levels of take on the extinction risk of the species in Ecuador
cannot be made with any certainty at this time.
In waters off Peru, smooth hammerhead sharks are also prevalent. In
fact, from 2006-2010, S. zygaena was the third most commonly landed
shark species (comprising 15 percent of the shark landings) by the
Peruvian small-scale fishery (Gonzalez-Pestana et al. 2014). In a 61-
year analysis of Peruvian shark fisheries, Gonzalez-Pestana et al.
(2014) noted a significant increase in the amount of reported landings
for smooth hammerhead sharks between 2000 and 2010, with peaks in 1998
and 2003. The authors estimated that landings increased by 7.14 percent
per year (confidence interval: 1.2-13.4 percent); however, if the 2003
estimates (which appear to strongly influence the analysis) are removed
from the dataset, smooth hammerhead landings show a fairly stable trend
since 1999 (<500 t). Based on the latest available landings figure from
2014 of 364 t, this trend does not appear to have changed (Instituto
del Mar del Peru 2014). However, as Gonzalez-Pestana et al. (2014)
note, without accompanying information on fishing effort, it is
difficult to fully understand the dynamics of the shark fishery, and
particularly, in this case, its impact on the smooth hammerhead
population.
In terms of the data from the RFMO that operates within the Eastern
Pacific, the Inter-American Tropical Tuna Commission (IATTC), bycatch
of hammerhead sharks has been variable between 1993 and 2013.
Specifically, catches of hammerhead sharks by large purse seine vessels
peaked in 2003-
[[Page 41949]]
2004, at around 3,000 sharks, before significantly decreasing. This
decline is thought to be, in part, a result of purse seiners moving
fishing effort farther offshore in recent years to waters with fewer
hammerhead sharks, but could also reflect a decline in the actual
abundance of hammerhead sharks (Hall and Roman 2013). Since 2006,
annual bycatch of hammerhead sharks has fluctuated between 750 and
1,400 individuals (Rom[aacute]n-Verdesoto and Hall 2014). The
Scientific Advisory Committee to the IATTC noted that this purse-seine
catch may represent only a relatively small portion of the overall
harvest of hammerhead sharks in this region, with insufficient data
(due to the rarity of Sphyrna spp. in the catch) to provide for a
meaningful analysis. Rather, the Committee indicated that the majority
of harvest in this region is likely taken by the artisanal fisheries
(Hall and Roman 2013; IATTC 2015). However, as already discussed, and
further acknowledged by others in reviewing the IATTC information (Hall
and Roman 2013; Rom[aacute]n-Verdesoto 2015), the data from these
artisanal fishing operations are, for the most part, largely
unavailable or not of the detail needed (e.g., species-specific with
corresponding fishing effort over time) to examine impacts on the
populations (Hall and Roman 2013; Rom[aacute]n-Verdesoto 2015). Thus,
at this time, the best available information does not provide evidence
that overutilization is a threat significantly contributing to the
species' risk of extinction in the Eastern Pacific portion of its
range.
Shark Fin Trade
As noted in the above regional reviews examining utilization of the
species, hammerhead sharks are primarily targeted and valued
particularly for their fins. As hammerhead fins tend to be large in
size, with high fin needle content (a gelatinous product used to make
shark fin soup), they are one of the most valuable fins in the
international market. Based on 2003 figures, smooth hammerhead shark
fins fetch prices as high as $88/kg (Abercrombie et al. 2005). In the
Hong Kong fin market, which is the largest fin market in the world, S.
lewini and S. zygaena are mainly traded under a combined market
category called Chun chi, and found in a 2:1 ratio, respectively
(Abercrombie et al. 2005; NMFS 2014a). Based on an analysis of the Hong
Kong fin data from 2000-2002, Chun chi was the second most traded
category, comprising around 4-5 percent of the annual total fins
(Clarke et al. 2006a), and translating to around 1.3-2.7 million
individuals of scalloped and smooth hammerhead sharks (equivalent to a
biomass of 49,000-90,000 tons) traded each year (Clarke et al. 2006b).
By 2003-2004, both global catches of chondrichthyans and trade in shark
fins peaked (Dent and Clarke 2015; Eriksson and Clarke 2015). However,
as the impacts of this exploitation, particularly of chondrichthyan
species to match the demand for their fins, became increasingly more
apparent, many countries and states began passing management measures
and regulations to discourage and dis-incentivize fishermen from
targeting vulnerable sharks, and particularly their fins, for the
international shark fin trade (PEW Environment Group 2012; Whitcraft et
al. 2014; Miller 2016). Between 2008 and 2011, quantities of
chondrichthyan catches and trade in shark fins leveled out at around
82-83 percent of the peak figure (Dent and Clarke 2015; Eriksson and
Clarke 2015). In 2012, the trade in shark fins through China, Hong Kong
Special Administrative Region (SAR), which has served as an indicator
of the global trade for many years, saw a decrease of 22 percent from
2011 figures, indicating that recent government-led backlash against
conspicuous consumption in China, combined with the global conservation
momentum, appears to have had an impact on traded volumes (Dent and
Clarke 2015; Eriksson and Clarke 2015). Dent and Clarke (2015) also
note that a number of other factors may have contributed to this
downturn in the trade of fins through Hong Kong SAR, including:
Increased domestic chondrichthyan production by the Chinese fleet,
increased monitoring and regulation of finning, a change in trade
dynamics, other trade bans and curbs, and an overall growing
conservation awareness. Potentially, if the demand for fins continues
to decrease in the future, so will the direct targeting of hammerhead
sharks (and illegal fishing of the species--see Inadequacy of Existing
Regulatory Measures). Additionally, with the listing of the species on
CITES Appendix II, for those countries unable to make NDFs, such as
Japan, the incentives for fishermen to target or retain hammerhead
sharks for trade will also likely decline and contribute to a decrease
in fishing pressure. The extent (magnitude) to which this decrease in
fishing pressure will translate to a decrease in mortality of the
species is currently unclear, but will likely only benefit the species.
As such, at this time, the best available information does not indicate
that overutilization, including the demand for smooth hammerhead sharks
in the shark fin trade, is a threat significantly contributing to the
species' risk of extinction throughout its global range, now or in the
foreseeable future.
Disease or Predation
No information has been found to indicate that disease or predation
is a factor that is negatively affecting the status of smooth
hammerhead sharks. These sharks have been documented as hosts for the
nematodes Parascarophis sphyrnae and Contracaecum spp. (Knoff et al.
2001); however, no data exist to suggest these parasites are affecting
S. zygaena abundance. Additionally, predation is also not thought to be
a factor negatively influencing smooth hammerhead shark abundance. The
most significant predator on smooth hammerhead sharks is likely humans;
however, a study from New Zealand observed two killer whales (Orcinus
orca) feeding on a small, juvenile (~100 cm TL) smooth hammerhead shark
(Visser 2005). In a 12-year period that documented 108 encounters with
New Zealand killer whales, only 1 smooth hammerhead shark was preyed
upon (Visser 2005); thus, predation on S. zygaena by killer whales is
likely opportunistic and not a contributing factor to abundance levels
of smooth hammerhead sharks. Juvenile smooth hammerhead sharks also
likely experience predation by adult sharks (including their own
species); however, the rate of juvenile predation and the subsequent
impact to the status of smooth hammerhead sharks is unknown. As such,
at this time, the best available information does not indicate that
disease or predation are threats significantly contributing to the
species' risk of extinction throughout its global range, now or in the
foreseeable future.
The Inadequacy of Existing Regulatory Mechanisms
Although none of the previously discussed ESA section 4(a)(1)
factors were identified as significant threats to S. zygaena, existing
regulatory mechanisms in some portions of the species' range could be
strengthened (or better enforced) to promote the long-term viability of
the species. For example, in a recent study that examined current
regulatory and management measures for smooth hammerhead sharks,
including data collection requirements and level of compliance, Lack et
al. (2014) concluded that additional management measures (particularly
species-specific management measures) could benefit the species. For a
comprehensive list of current management measures
[[Page 41950]]
pertaining to hammerhead sharks, as well as sharks in general, see the
Appendix in Miller (2016).
Despite the number of existing regulatory measures in place to
protect sharks and promote sustainable fishing, enforcement tends to be
difficult, and illegal fishing has emerged as a problem in many
fisheries worldwide. Specifically, illegal fishing occurs when vessels
or harvesters operate in violation of the laws of a fishery. In order
to justify the risks of detection and prosecution involved with illegal
fishing, efforts tend to focus on high value products (e.g., shark
fins) to maximize returns to the illegal fishing effort. Thus, as the
lucrative market for shark products, particularly shark fins,
developed, so did increased targeting, both legal and illegal, of
sharks around the world. Given that illegal fishing tends to go
unreported, it is difficult to determine, with any certainty, the
proportion of current fishery-related mortality rates that can be
attributed to this activity. This is particularly true for smooth
hammerhead sharks, where even legal catches go unreported. A study that
provided regional estimates of illegal fishing (using FAO fishing areas
as regions) found the Western Central Pacific (Area 71) and Eastern
Indian Ocean (Area 57) regions have relatively high levels of illegal
fishing (compared to the rest of the regions), with illegal and
unreported catch constituting 34 percent and 32 percent of the region's
catch, respectively (Agnew et al. 2009). The annual value of high seas
illegal, unreported and unregulated (IUU) catches of sharks worldwide
has been estimated at $192 million (High Seas Task Force 2006) and
annual worldwide economic losses from all IUU fishing is estimated to
be between $10 billion and $23 billion (NMFS 2015d).
However, as mentioned in the Overutilization for Commercial,
Recreational, Scientific or Educational Purposes section of this
finding, given the recent downward trend in the trade of shark fins
(Dent and Clarke 2015; Eriksson and Clarke 2015), illegal fishing for
the sole purpose of shark fins may not be as prevalent in the future.
It is also a positive sign that most (70 percent) of the top 26 shark-
fishing countries, areas and territories have taken steps to combat IUU
fishing, either by signing the Port State Measures Agreement (46
percent) or by adopting a National Plan of Action to prevent, deter,
and eliminate IUU or similar plan (23 percent) (Fischer et al. 2012).
However, whether these agreements or plans translate to less IUU
fishing activity is unclear. For example, in quite a few countries, the
effective implementation of monitoring, control, and surveillance
schemes is problematic, often due to a lack of personnel and financial
resources (Fischer et al. 2012), and a number of instances of IUU
fishing, specifically involving sharks, have been documented over the
past decade. For instance, as recently as May 2015, it was reported
that Ecuadorian police confiscated around 200,000 shark fins from at
least 50,000 sharks after raids on 9 locations in the port of Manta
(BBC 2015). In September 2015, Greenpeace activists boarded a Taiwan-
flagged boat fishing near Papua New Guinea and found 110 shark fins but
only 5 shark carcasses (which was in violation of both the Taiwanese
and the WCPFC rules requiring onboard fins to be at most 5 percent of
the weight of the shark carcasses) (News24 2015). Recreational
fishermen have also been caught with illegal shark fins. A report from
June 2015 identified 3 unlicensed recreational fishers operating in
waters off Queensland, Australia, and in possession of 3,200 illegal
shark fins most likely destined for the black market (Buchanan and
Sparkes 2015). While these reports provide just a few examples of
recent illegal fishing activities, more evidence and additional reports
of specific IUU fishing activities throughout the world can be found in
Miller et al. (2014a) and Miller et al. (2014b).
In terms of tracking IUU fishing, most of the RFMOs maintain lists
of vessels they believe to be involved in illegal fishing activities,
with the latest reports on this initiative seeming to indicate
improvement in combatting IUU. In the most recent 2015 Biennial Report
to Congress, which highlights U.S. findings and analyses of foreign IUU
fishing activities, NMFS reports that all 10 nations that were
previously identified in the 2013 Biennial Report for IUU activities
took appropriate actions to address the violations (e.g., through
adoption of new laws and regulations or by amending existing ones,
sanctioning vessels, and improving monitoring and enforcement) (NMFS
2015c). In the current report, 6 countries were identified for having
vessels engaged in IUU fishing activities; however, no countries were
identified for engaging in protected living marine resources bycatch or
for catching sharks on the high seas (although NMFS caveats this by
noting the inability to identify nations due primarily to the
restrictive time frames and other limitations in the statute) (NMFS
2015b).
While it is likely that S. zygaena is subject to IUU fishing,
particularly for its valuable fins, based on the best available
information on the species' population trends throughout its range, as
well as present utilization levels, the mortality rates associated with
illegal fishing and impacts on smooth hammerhead shark populations do
not appear to be contributing significantly to the species' extinction
risk. Furthermore, illegal fishing activities will likely decrease in
the future as nations step up to combat IUU fishing and as the demand
for shark fins declines. As such, at this time, the best available
information does not indicate that the inadequacy of existing
regulatory measures is a threat significantly contributing to the
species' risk of extinction throughout its global range, now or in the
foreseeable future.
Other Natural or Man-Made Factors Affecting Its Continued Existence
In terms of other natural or manmade factors, environmental
pollutants were identified as a potential threat to the species. Many
pollutants in the environment, such as brevotoxins, heavy metals, and
polychlorinated biphenyls, have the ability to bioaccumulate in fish
species. Because of the higher trophic level position and longevity of
hammerhead sharks, these pollutants tend to biomagnify in liver, gill,
and muscle tissues (Storelli et al. 2003; Garc[iacute]a-
Hern[aacute]ndez et al. 2007; Marsico et al. 2007; Escobar-Sanchez et
al. 2010; Maz-Courrau et al. 2012; Lee et al. 2015). A number of
studies have attempted to study and quantify the concentration levels
of these pollutants in fish species, but with a focus on human
consumption and safety (Storelli et al. 2003; Garc[iacute]a-
Hern[aacute]ndez et al. 2007; Marsico et al. 2007; Escobar-Sanchez et
al. 2010; Maz-Courrau et al. 2012; Lee et al. 2015). As such, many of
the results from these studies may indicate either ``high'' or ``low''
concentrations in fish species, but this is primarily in comparison to
recommended safe concentrations for human consumption and does not
necessarily have any impact on the biological status of the species.
In terms of smooth hammerhead sharks, mercury appears to be the
most studied environmental pollutant in the species. International
agencies, such as the Food and Drug Administration and the World Health
Organization, have set a recommended maximum mercury concentration of 1
[mu]g/g wet weight in seafood tissues for human consumption. However,
observed mercury concentrations in the tissues of smooth hammerhead
sharks are highly variable.
[[Page 41951]]
For example, Storelli et al. (2003) tested tissue samples from four
smooth hammerhead sharks from the Mediterranean Sea (size range: 277-
303 cm TL) and found that, on average, tissue samples from the liver
and muscle had concentrations of mercury that greatly exceeded the 1
[mu]g/g recommended limit. Mean mercury concentration in muscle samples
were 12.15 4.60 [mu]g/g and mercury concentration in liver
samples averaged 35.89 3.58 [mu]g/g. Similarly,
Garc[iacute]a-Hern[aacute]ndez et al. (2007) found high concentrations
of mercury in tissues of four smooth hammerhead sharks (size range:
163-280 cm TL) from the Gulf of California, Mexico, with mean mercury
concentration in muscle tissue of 8.25 9.05 [mu]g/g. In
contrast, Escobar-Sanchez et al. (2010) tested muscle tissue of 37
smooth hammerhead sharks from the Mexican Pacific (Baja California Sur,
Mexico; size range: >55-184 cm TL) and found mercury concentrations
were below the maximum safety limit of 1 [mu]g/g (average = 0.73 [mu]g/
g; median = 0.10 [mu]g/g). Out of the 37 studied sharks, only one shark
had a mercury concentration that exceeded the recommended limit (1.93
[mu]g/g). Likewise, Maz-Courrau et al. (2012) also found ``safe''
concentrations of mercury in smooth hammerhead sharks from the Baja
California peninsula. Analysis of muscle tissue samples from 31 smooth
hammerhead sharks (mean size = 114 cm TL 19.2) showed an
average mercury concentration of 0.98 0.92 [mu]g/g dry
weight (range: 0.24-2.8 [mu]g/g). The authors also tested mercury
concentrations in four prey species of Pacific sharks (mackerel Scomber
japonicus, lantern fish Symbolophorus evermanni, pelagic red crab
Pleuroncodes planipes, and giant squid Dosidicus gigas) and found that
D. gigas, a common prey item for smooth hammerhead sharks (see Diet and
Feeding), had the lowest mercury concentration (0.12 0.05
[mu]g/g). The authors suggest that the transfer of mercury to smooth
hammerhead sharks is unlikely to come from feeding on cephalopods;
however, these results may very well explain the observed low levels of
mercury in smooth hammerhead shark tissues (i.e., because these sharks
prefer to feed on cephalopods, bioaccumulation of mercury in tissues
would likely be low).
In Atlantic waters, Marsico et al. (2007) also found that smooth
hammerhead sharks had relatively low levels of mercury concentrations
(in comparison to the recommended 1 [mu]g/g human consumption limit).
Based on muscle tissue samples from 5 smooth hammerhead sharks caught
off the coast of Santa Catarina, Brazil, average mercury concentration
was 0.443 0.299 [mu]g/g with a range of 0.015-0.704 [mu]g/
g. In Indo-Pacific waters, the only information on S. zygaena mercury
bioaccumulation is an analysis of muscle tissue from a single smooth
hammerhead that was caught off Port Stephens, NSW, Australia (Paul et
al. 2003). The smooth hammerhead shark was 232 cm in length and had a
muscle tissue mercury concentration of 1.9 [mu]g/g.
Based on the above information, it appears that mercury
concentrations may correlate with size of the smooth hammerhead shark,
with larger sharks, such as those examined in the Paul et al. (2003),
Storelli et al. (2003), and Garc[iacute]a-Hern[aacute]ndez et al.
(2007) studies, containing higher mercury concentrations. However,
analyses examining this very relationship show conflicting results
(Escobar-Sanchez et al. (2010)--no correlation; Maz-Courrau et al.
(2012)--significant correlation). Furthermore, the effect of these and
other mercury concentrations in smooth hammerhead shark populations,
and potential risk to the viability of the species, remains unknown. It
is hypothesized that these apex predators can actually handle higher
body burdens of anthropogenic toxins due to the large size of their
livers which ``provides a greater ability to eliminate organic
toxicants than in other fishes'' (Storelli et al. 2003) or may even be
able to limit their exposure by sensing and avoiding areas of high
toxins (like during K. brevis red tide blooms) (Flewelling et al.
2010). Currently, the impact of toxin and metal bioaccumulation in
smooth hammerhead shark populations is unknown. In fact, there is no
information on the lethal concentration limits of toxins or metals in
smooth hammerhead sharks, or evidence to suggest that current
concentrations of environmental pollutants are causing detrimental
physiological effects to the point where the species may be at an
increased risk of extinction. As such, at this time, the best available
information does not indicate that the present bioaccumulation rates
and concentrations of environmental pollutants in the tissues of smooth
hammerhead sharks are threats significantly contributing to the
species' risk of extinction throughout its global range, now or in the
foreseeable future.
Threats Assessment Summary
Based on the best available information summarized above and
discussed in more detail in the status review (Miller 2016), none of
the ESA Section 4(a)(1) factors, either alone or in combination with
each other, are identified as threats significantly contributing to the
extinction risk of the species. While overutilization poses the largest
potential threat to the species, based on the best available data
throughout the species' range, present fishery-related mortality rates
of the shark do not appear to be affecting the species' demographics to
such a degree that cause it to be strongly influenced by stochastic or
depensatory processes or on a trajectory toward this point.
In the Atlantic Ocean, where species-specific data is available,
the regional and local information indicates that smooth hammerhead
sharks tend to be a rare occurrence, observed only sporadically in the
fisheries data and in low numbers. In the northwest Atlantic, harvest
and bycatch of the species is very low and strong management measures
are in place to prevent overfishing of the species. In the southwest
Atlantic, while the majority of the catch appears to be juveniles,
smooth hammerhead sharks are generally harvested at low levels and
comprise a small proportion of the fisheries catch. In the temperate
waters of the Mediterranean Sea, smooth hammerhead sharks were
historically a common occurrence. However, with the intense coastal
fishing and the expansion of the tuna and swordfish longline and drift
net fisheries in the 1970s, smooth hammerhead sharks have been fished
almost to extinction in the Mediterranean Sea. Fishing pressure remains
high in this portion of the species' range, which will likely result in
additional fishing mortality and continued declines in the population.
However, the Mediterranean comprises only a small portion of the
species' range, and given the lack of trends or evidence of significant
declines elsewhere in the Atlantic, the available data do not indicate
that the overutilization and depletion of the Mediterranean population
has significantly affected other S. zygaena populations in the
Atlantic.
Similarly, in the Indian and Pacific Oceans, the available data,
albeit severely lacking, depict a species that is not regularly caught,
or caught in large numbers, by fisheries operating in these regions.
The majority of fishing effort, particularly in the Indian Ocean, tends
to be concentrated in more tropical waters, thereby decreasing the
threat of overutilization by these fisheries on the more temperately-
distributed smooth hammerhead shark. However, in the Western Pacific,
there are a number of fisheries operating within the temperate
[[Page 41952]]
portions of this region (e.g., off Japan, Australia, New Zealand) that
report regular catches of smooth hammerhead sharks. Based on the
available data from these fisheries, including catch time series and
CPUE data, no clear trends were found that would suggest
overutilization is a significant threat to the species. In the Eastern
Pacific, artisanal fisheries are responsible for the majority of the
smooth hammerhead catch, and land primarily juveniles of the species.
However, based on preliminary information on catch trends (primarily
from Peru and Ecuador), there is no evidence to suggest that this level
of utilization has or is significantly impacting recruitment to the
population.
Furthermore, the number of regulatory and management measures,
including hammerhead retention bans and finning regulations, as well as
the creation of shark sanctuaries, has been on the rise in recent
years. These regulations are aimed at decreasing the amount of sharks
being landed or finned just for the shark fin trade and work to dis-
incentivize fishermen from targeting vulnerable shark species.
Additionally, with the CITES Appendix II listing, mechanisms are also
now in place to monitor and control international trade in the species
and ensure that this trade is not detrimental to the survival of the
species in the wild. Already it appears that the demand for shark fins
is on the decline. While it is unclear how effective these regulations
will be in ultimately reducing fishing mortality rates for the smooth
hammerhead shark (given their high at-vessel mortality rates), it is
likely to decrease fishing pressure on the species, particularly in
those fisheries that target the species and by those fishermen that
illegally fish for the species solely for the shark fin trade.
Overall, while there is a clear need for further research and data
collection on smooth hammerhead sharks, the best available information
at this time does not indicate that any of the ESA Section 4(a)(1)
factors, or a combination of these factors, are significantly
contributing to the extinction risk of the species throughout its
global range, now or in the foreseeable future.
Overall Risk Summary
While the species' life history characteristics increase its
inherent vulnerability to depletion, and likely contributed to past
population declines of varying magnitudes, the best available
information suggests that present demographic risks are low. Smooth
hammerhead sharks continue to be exploited throughout their range,
particularly juveniles of the species. While it is universally
acknowledged that information is severely lacking for the species,
including basic catch and effort data from throughout the species'
range, global, regional, and local population size estimates, abundance
trends, life history parameters (particularly from the Pacific and
Indian Oceans), and distribution information, the best available data
do not indicate that present fishing levels and associated mortality,
habitat modification, disease, predation, environmental pollutant
levels, or a combination of these factors, are causing declines in the
species to such a point that the species is at risk of extinction or
likely to become so in the foreseeable future. Thus, guided by the
results from the demographic risk analysis and threats assessment, we
conclude that the smooth hammerhead shark is currently at a low risk of
extinction throughout all of its range.
Significant Portion of Its Range
The definitions of both ``threatened'' and ``endangered'' under the
ESA contain the term ``significant portion of its range'' as an area
smaller than the entire range of the species which must be considered
when evaluating a species risk of extinction. On July 1, 2014, the
Services published the SPR Policy, which provides our interpretation
and application for how to evaluate whether a species is in danger of
extinction, or likely to become so in the foreseeable future, in a
``significant portion of its range'' (79 FR 37578; July 1, 2014).
Because we found that the smooth hammerhead shark is at a low risk
of extinction throughout its range, under the SPR Policy, we must go on
to evaluate whether the species is in danger of extinction, or likely
to become so in the foreseeable future, in a ``significant portion of
its range.'' The SPR Policy explains that it is necessary to fully
evaluate a particular portion for potential listing under the
``significant portion of its range'' authority only if substantial
information indicates that the members of the species in a particular
area are likely both to meet the test for biological significance and
to be currently endangered or threatened in that area. Making this
preliminary determination triggers a need for further review, but does
not prejudge whether the portion actually meets these standards such
that the species should be listed. To identify only those portions that
warrant further consideration, we will determine whether there is
substantial information indicating that (1) the portions may be
significant and (2) the species may be in danger of extinction in those
portions or likely to become so within the foreseeable future. We
emphasize that answering these questions in the affirmative is not a
determination that the species is endangered or threatened throughout a
significant portion of its range--rather, it is a step in determining
whether a more detailed analysis of the issue is required (79 FR 37578,
at 37586; July 1, 2014).
Thus, the preliminary determination that a portion may be both
significant and endangered or threatened merely requires us to engage
in a more detailed analysis to determine whether the standards are
actually met (79 FR 37578, at 37587). Unless both standards are met,
listing is not warranted. The SPR policy further explains that,
depending on the particular facts of each situation, we may find it is
more efficient to address the significance issue first, but in other
cases it will make more sense to examine the status of the species in
the potentially significant portions first. Whichever question is asked
first, an affirmative answer is required to proceed to the second
question. Id. ``[I]f we determine that a portion of the range is not
`significant,' we will not need to determine whether the species is
endangered or threatened there; if we determine that the species is not
endangered or threatened in a portion of its range, we will not need to
determine if that portion is `significant' '' Id. Thus, if the answer
to the first question is negative--whether that regards the
significance question or the status question--then the analysis
concludes and listing is not warranted.
As defined in the SPR Policy, a portion of a species' range is
``significant'' ``if the species is not currently endangered or
threatened throughout its range, but the portion's contribution to the
viability of the species is so important that, without the members in
that portion, the species would be in danger of extinction, or likely
to become so in the foreseeable future, throughout all of its range''
(79 FR 37578, at 37609). For purposes of the SPR Policy, ``[t]he range
of a species is considered to be the general geographical area within
which that species can be found at the time FWS or NMFS makes any
particular status determination. This range includes those areas used
throughout all or part of the species' life cycle, even if they are not
used regularly (e.g., seasonal habitats). Lost historical range is
relevant to the analysis of the status of the species, but it cannot
constitute a significant portion of a species' range'' Id.
[[Page 41953]]
Applying the SPR policy to the smooth hammerhead shark, we first
evaluated whether there is substantial information indicating that any
portions of the species' range may be significant. After a review of
the best available information, we find that the data do not indicate
any portion of the smooth hammerhead shark's range as being more
significant than another. Smooth hammerhead sharks are highly mobile,
with a global distribution, and very few restrictions governing their
movements. While the Mediterranean region was recognized as a portion
of the species' range in which it is likely at risk of extinction due
to threats of overutilization, the Mediterranean represents only a
small portion of the global range of the smooth hammerhead sharks.
Furthermore, there is no indication that loss of that part of the
species' range would constitute a moderate or high extinction risk to
the global species, now or in the foreseeable future. As was mentioned
previously, the available population and trend data do not indicate
that the depletion of the Mediterranean population has significantly
affected other S. zygaena populations. Thus, the Mediterranean would
not qualify as ``significant'' under the SPR Policy.
Likewise, there is no substantial evidence to indicate that the
loss of genetic diversity from one portion of the species' range (such
as loss of an ocean basin population) would result in the remaining
populations lacking enough genetic diversity to allow for adaptations
to changing environmental conditions. Similarly, there is no
information to suggest that loss of any portion would severely fragment
and isolate the species to the point where individuals would be
precluded from moving to suitable habitats or have an increased
vulnerability to threats. In other words, loss of any portion of its
range would not likely isolate the species to the point where the
species would be at risk of extinction from demographic processes, or
likely to be so in the foreseeable future, throughout all of its range.
Areas exhibiting source-sink dynamics, which could affect the
survival of the species, were not evident in any part of the smooth
hammerhead sharks' range. There is also no evidence of a portion that
encompasses aspects that are important to specific life history events,
but another portion that does not, where loss of the former portion
would severely impact the growth, reproduction, or survival of the
entire species, now or in the foreseeable future. In fact, potential
pupping grounds and nursery areas for the species were identified in
all three major ocean basins. In other words, the viability of the
species does not appear to depend on the productivity of the population
or the environmental characteristics in any one portion.
It is important to note that the overall distribution of the smooth
hammerhead shark is still uncertain, considered to be generally patchy
but also unknown in large areas, such as the Indian Ocean. As better
data become available, the species distribution (and potentially
significant portions of its range) will become better resolved;
however, at this time, there is no evidence to suggest that any
specific portion of the species' range has increased importance over
another with respect to the species' survival. As such, we did not
identify any portions of the species' range that meet both criteria
under the SPR Policy (i.e., the portion is biologically significant and
the species may be in danger of extinction in that portion, or likely
to become so within the foreseeable future). Therefore, listing is not
warranted under the SPR policy.
Distinct Population Segment Analysis
The ESA's definition of ``species'' includes ``any subspecies of
fish or wildlife or plants, and any distinct population segment of any
species of vertebrate fish or wildlife which interbreeds when mature.''
Our DPS Policy clarifies our interpretation of the phrase ``distinct
population segment'' for the purposes of listing, delisting, and
reclassifying a species under the ESA (61 FR 4722; February 7, 1996).
In the 90-day finding addressing the smooth hammerhead shark petition,
we stated that we would consider whether the populations requested by
the petitioner qualify as DPSs pursuant to our DPS Policy and warrant
listing (80 FR 48052; August 11, 2015).
When identifying a DPS, our DPS policy stipulates two elements that
must be considered: (1) The discreteness of the population segment in
relation to the remainder of the species (or subspecies) to which it
belongs; and (2) the significance of the population segment to the
remainder of the species (or subspecies) to which it belongs. In terms
of discreteness, the DPS policy states that a population of a
vertebrate species may be considered discrete if it satisfies either
one of the following conditions: (1) It is markedly separated from
other populations of the same taxon as a consequence of physical,
physiological, ecological, or behavioral factors (quantitative measures
of genetic or morphological discontinuity may provide evidence of this
separation) or (2) it is delimited by international governmental
boundaries within which differences in control of exploitation,
management of habitat, conservation status, or regulatory mechanisms
exist that are significant in light of Section 4(a)(1)(D) of the ESA.
If a population segment is considered discrete under one or more of the
above conditions, then its biological and ecological significance is
considered. Significance under the DPS policy is evaluated in terms of
the importance of the population segment to the overall welfare of the
species. Some of the considerations that can be used to determine a
discrete population segment's significance to the taxon as a whole
include: (1) Persistence of the population segment in an unusual or
unique ecological setting; (2) evidence that loss of the population
segment would result in a significant gap in the range of the taxon;
(3) evidence that the discrete population segment represents the only
surviving natural occurrence of a taxon that may be more abundant
elsewhere as an introduced population outside its historic range; or
(4) evidence that the population segment differs markedly from other
populations of the species in its genetic characteristics.
The petition states that the smooth hammerhead shark is comprised
of five DPSs: Northeast Atlantic and Mediterranean Sea, Northwest
Atlantic, Southwest Atlantic, Eastern Pacific, and Indo-West Pacific.
However, the petition provides no boundary lines for these identified
population segments. As such, it is difficult to determine the
discreteness and significance of these populations without knowing how
to separate these populations, such as the Northwest and Southwest
Atlantic populations. Therefore, we had to make assumptions regarding
the boundary lines. Below we explain where we made assumptions and
provide our evaluation of the qualification of these populations as
DPSs under our DPS policy.
In terms of discreteness, the petition asserts that the identified
populations are ``markedly separate from each other as a result of
multiple types of barriers that separate the different populations.''
Specifically, the petition identifies deep ocean areas as areas that
contain the ``wrong habitat'' for the species and which act as barriers
to movement between the petition's identified populations. The petition
cites Bester (undated) and Hayes (2007) as support that the species
avoids open-ocean and trans-oceanic movements. Additionally, the
petitioner cites Diemer et al. (2011) to support its statement that the
smooth hammerhead shark has less vagility, or freedom to move about,
compared to
[[Page 41954]]
other shark species, therefore making it unlikely that ``populations
will connect or reconnect even if they are only separated by relatively
short distances.''
In evaluating the information within Bester (undated), we found no
data to suggest that the species cannot make open-ocean or trans-
oceanic movements. In the Hayes (2007) paper, the author notes ``As
semi-oceanic species, they [hammerhead sharks] can be found from
continental and insular shelves to deeper water just beyond the
shelves, but avoid open-ocean and transoceanic movements (Compagno,
1984).'' This statement refers generally to hammerhead sharks and does
not specify species. Additionally, in reviewing the Compagno (1984)
reference in Hayes (2007), there is no information to indicate that the
species is not capable of these movements. In fact, in describing the
habitat and biology of smooth hammerhead sharks, Compagno (1984) states
that the species is an ``active, common, coastal-pelagic and semi-
oceanic hammerhead, found . . . at depths from the surface down to at
least 20 m and probably much more.'' While the petitioner notes that
this species may be less vagile than other species of sharks (that
share similar depth ranges), thus suggesting a low potential for mixing
of S. zygaena populations, we have no evidence to indicate that any
populations of the smooth hammerhead shark are, in fact, markedly
separated from other populations of the species.
In our review of the best scientific and commercial information
available, we found evidence to indicate that smooth hammerhead sharks
are capable of long-distance movements, and, hence, the ability to
potentially mix with other populations, with no data to suggest that
they could not make trans-oceanic migrations. While the petition only
references Diemer et al. (2011) as support for limited maximum and
average annual movements, and, thus, low vagility for smooth hammerhead
sharks (i.e., 384 km and 141.8 km, respectively), we found three
additional studies that provided information on movements of S.
zygaena, and whose results indicate that S. zygaena travels
significantly farther distances than those reported in the petition.
For example, Kohler and Turner (2001) provided available tagging data
from recaptured adult smooth hammerhead sharks (n = 6) and found
observed maximum distance travelled for S. zygaena to be 919 km, with a
maximum speed of 4.8 km/day. In June 2015, NOAA scientists tagged a
female smooth hammerhead shark (~213 cm FL) off San Clemente Island,
CA. Data from the tag showed that the animal traveled more than 400
miles south to the central Baja Peninsula and then returned north to
waters off Ventura, CA, making the total distance traveled equal to
more than 1,000 miles (>1,609 km) (SWFSC 2015). Clarke et al. (2015)
also noted the ability of the species to travel significant distances,
citing a study off New Zealand that found tagged individuals traveled
to Tonga, a distance of around 1,200 nm (2,222 km). In fact, Clarke et
al. (2015) characterized S. zygaena as the most oceanic of the
hammerhead species. This characterization is further supported by
Kohler et al. (1998), who showed tagging locations of S. zygaena in the
central Atlantic Ocean, between 20[deg] W. and 30[deg] W. longitudes,
indicating the presence of the species in open-ocean water areas. The
presence of smooth hammerhead sharks in oceanic waters is also
confirmed by fisheries data from the southwest Atlantic (Amorim et al.
2011), tropical Atlantic Ocean (Matsushita and Matsunaga 2002; Dai et
al. 2009), and eastern Pacific Ocean (Rom[aacute]n-Verdesoto 2015).
Given the above information on long-distance movements and presence in
oceanic waters, we do not find that the populations identified by the
petitioner are markedly separate from each other as a consequence of
physical or habitat barriers.
The petition also asserts that populations of smooth hammerhead
sharks are genetically distinct from each other, but notes that ``there
is not extensive species-specific genetic differentiation information
available.'' The petition cites Duncan et al. (2006), who examined the
global phylogeography of the scalloped hammerhead shark and compared
haplotypes of S. lewini to those of nine individuals of S. zygaena. The
origin of these 9 S. zygaena samples were only identified as Atlantic
(n = 6), Pacific (n = 2) and Indian (n = 1). The authors found high
haplotype diversity for smooth hammerhead sharks (similar to the
variation in scalloped hammerhead haplotype diversity); however, this
analysis was based on very few samples of S. zygaena from non-specific
locations and, therefore, provides no information regarding the genetic
discreteness of the petitioner's identified populations, particularly
between the Northeast Atlantic and Mediterranean Sea, Northwest
Atlantic, and Southwest Atlantic populations, and between the Eastern
Pacific and Indo-West Pacific populations. Additionally, the Duncan et
al. (2006) study examined mitochondrial DNA (mtDNA). Mitochondrial DNA
is maternally-inherited, and, as such, differences in mtDNA haplotypes
between populations do not necessarily mean that the populations are
substantially reproductively isolated from each other because they do
not provide any information on males. As demonstrated in previous
findings, in species where female and male movement patterns differ
(such as philopatric females but wide-ranging males), analysis of mtDNA
may indicate discrete populations, but analysis of nuclear (or bi-
parentally inherited) DNA could show homogenous populations as a result
of male-mediated gene flow (see e.g.,loggerhead sea turtle, 68 FR
53947, September 15, 2003, and sperm whale, 78 FR 68032, November 13,
2013).
The petitioners also cite to the genetic information provided in
Abercrombie et al. (2005) as support of the genetic differentiation
between Pacific and Atlantic Ocean smooth hammerhead individuals.
However, similar to the discussion above, this analysis was based on
very few S. zygaena samples from non-specific locations (n = 7 samples
from Atlantic; n = 34 from Pacific) and, therefore, provides no
information regarding the genetic discreteness of the petitioner's
identified populations, particularly between the Atlantic populations
and between the Indo-West and Eastern Pacific populations.
Additionally, neither the petitioner, nor the information in the
Abercrombie et al. (2005), discuss the relative importance of the
differences in the observed amplicons (segments of chromosomal DNA that
undergo amplification and contain replicated genetic material) between
the Atlantic and Pacific S. zygaena primers (strands of short nucleic
acid sequences that serve as starting points for DNA synthesis) in
terms of genetic diversity between these populations. Finally, the
petition cites fossil records (Lim et al. 2010) as evidence that would
support genetic differentiation amongst populations. The Lim et al.
(2010) study used samples of S. zygaena from only one location (South
Africa) to examine the phylogeny of all hammerhead species. The study
provides no information on the genetic differentiation amongst the
populations identified by the petitioner.
As discussed previously in this finding, as well as in the smooth
hammerhead shark status review (Miller 2016), very few studies have
examined the population structure of S. zygaena. In addition to the
studies referenced by the petitioner, we evaluated two other available
genetic studies (Naylor et al. (2012) and Testerman (2014)) to
determine if they provided evidence to
[[Page 41955]]
support the discreteness of the petitioner's identified populations.
Similar to the Duncan et al. (2006) study, Naylor et al. (2012)
analyzed mtDNA from S. zygaena individuals. This study also suffered
from a small sample size (n = 16), but provided specific locations of
the analyzed specimens (4 from Gulf of California, 6 from Northwest
Atlantic, 3 from Taiwan, and 1 each from Senegal, Vietnam, and Japan).
While these samples do not cover all of the identified petitioner's
populations (i.e., no samples from the Southwestern Atlantic,
Northeastern and Mediterranean, or Eastern Pacific), they provide some
limited information for evaluating the discreteness of the Northwestern
Atlantic and Indo-Pacific populations. The results from the Naylor et
al. (2012) study show a single cluster of smooth hammerhead sharks,
with no evidence to suggest matrilineal genetic partitioning of the
species. In other words, the available data do not indicate that the
identified Northwestern Atlantic population is markedly separate from
the Indo-Pacific population due to genetic differentiation.
In contrast, the Testerman (2014) study found statistically
significant matrilineal genetic structuring within oceanic basins and
significant genetic partitioning between oceanic basins. Specifically,
Testerman (2014) analyzed both mitochondrial control region sequences
(mtCR; n = 303, 1,090 bp) and 15 nuclear microsatellite loci (n = 332)
from smooth hammerhead sharks collected from eight regional areas:
Western North Atlantic (n = 21); western South Atlantic (n = 55);
western Indian Ocean (n = 63); western South Pacific (n = 44); western
North Pacific (n = 11); eastern North Pacific (n = 55); eastern
Tropical Pacific (n = 15); and eastern South Pacific (n = 26). Results
from the analysis of mtDNA indicated between-basin genetic structuring
between the Atlantic and Indo-Pacific basins (mtCR [phis]ST
= 0.8159), and shallow genetic variation among individuals from the
Atlantic, eastern Tropical/South Pacific, western North Pacific, and
western Indian Ocean. Analysis of the nuclear DNA (which is bi-
parentally inherited) also showed significant genetic structure between
ocean basins (nuclear FST = 0.0495), with the Atlantic and
Indo-Pacific considered to comprise two genetically distinct
populations (Testerman 2014). However, unlike the mtDNA results, no
significant structure was detected within oceanic basins using the
nuclear markers, suggesting evidence of potential female philopatry and
male mediated gene flow (Testerman 2014). In other words, the available
data support genetic differentiation on a broad scale, between the
Atlantic and Indo-Pacific basins, but do not provide genetic evidence
of the discreteness of the populations identified by the petitioner.
Furthermore, the Testerman (2014) study did not include samples from
all of the petitioner's identified populations, including the Northeast
Atlantic and Mediterranean population or the eastern Indian Ocean (with
the assumption that these individuals are part of the identified Indo-
West Pacific population). Additionally, as Testerman (2014) indicates,
more studies are needed, and in particular studies using samples from
individual smooth hammerhead sharks of known size class and gender, to
further refine the population structure of the smooth hammerhead shark
and confirm the above results. Given the best available information, we
do not find that the populations identified by the petitioners are
markedly separate from each other as a consequence of genetic
differences.
Finally, the petition asserts that the populations are ``delimited
by international governmental boundaries within which differences in
control of exploitation, management of habitat, conservation status,
and regulatory mechanisms exist.'' The petition notes that the range of
the smooth hammerhead shark is global, and, as such, extends across
international government boundaries and waters regulated by different
RFMOs. The petition references its discussion of the ``Inadequacy of
Existing Regulatory Mechanisms'' as evidence of the overutilization of
the species due to differences in control of exploitation of the
species, management of habitat, conservation status, and regulatory
mechanisms. The petition argues that because ``various international,
national, regional, and RFMO regulations relevant to the species exist
throughout all of the aforementioned populations, and since
exploitation in these populations varies, they all meet the
discreteness requirement.''
We find that the populations identified by the petitioner are not
delimited by international governmental boundaries within which
differences in control of exploitation, management of habitat,
conservation status, and regulatory mechanisms exist that are
significant in light of Section 4(a)(1)(D) of the ESA. Firstly, we note
that three of the petitioner's identified populations (the Northeast
Atlantic and Mediterranean Sea population, the Northwest Atlantic
population, and the Southwest Atlantic population) are governed by the
same RFMO, ICCAT. The ICCAT convention area covers all waters of the
Atlantic as well as adjacent Seas, including the Mediterranean. In
2010, ICCAT adopted recommendation 10-08 prohibiting the retention
onboard, transshipment, landing, storing, selling, or offering for sale
any part or whole carcass of hammerhead sharks of the family Sphyrnidae
(except for S. tiburo) taken in the Convention area in association with
ICCAT fisheries. In other words, these populations are not delimited by
international governmental boundaries within which differences in the
control of exploitation of the species exist as these populations are
all governed under the same RFMO, which presently prohibits the
retention and sale of the smooth hammerhead shark in its fisheries.
Additionally, the RFMO GFCM, whose convention area covers Mediterranean
waters and the Black Sea, passed a similar recommendation based on
ICCAT 10-08, further supporting the finding that the regulations
governing the exploitation of the Northeast Atlantic and Mediterranean
Sea population (e.g., the prohibition of retention and selling of S.
zygaena individuals) are no different than those governing the
exploitation of the Northwest Atlantic population or Southwest Atlantic
population.
Secondly, we did not find evidence of the overutilization of any of
the populations identified by the petitioner due to differences in
control of the exploitation of the species, management of habitat,
conservation status, or regulatory mechanisms across international
governmental boundaries. The status review report (Miller 2016)
provides a detailed discussion of the threat of overutilization, and
presents this analysis by region. These regional discussions
encapsulate the petitioner's identified populations, and, therefore,
can be used to evaluate whether differences in the control of
exploitation exist that are significant in light of Section 4(a)(1)(D)
of the ESA. However, since this finding has already discussed, in
detail, the threat of overutilization by region (see Overutilization
for Commercial, Recreational, Scientific or Educational Purposes
section), below we provide the conclusions as they relate to the
petitioner's identified populations.
In the Northwest Atlantic, we find that existing regulatory
measures have significantly decreased the mortality of hammerhead
sharks from both targeted fishing and bycatch mortality on fishing gear
for other large coastal shark species, with current levels unlikely to
[[Page 41956]]
lead to overutilization of the species. In the Southwest Atlantic, we
find that smooth hammerhead sharks tend to generally be harvested at
low levels and that the available species-specific information does not
indicate that overutilization is a significant threat presently
contributing to the species' risk of extinction in this region. In the
Indo-West Pacific, we find that the best available information,
including catch time series and CPUE data, does not indicate that
present utilization of the species is contributing significantly to its
risk of extinction within this region. In the Eastern Pacific, we find
that the best available information does not indicate that the species
has suffered declines to the point where it is at risk from depensatory
processes or that present utilization levels are impacting populations
of S. zygaena to such a degree that would significantly increase the
species' risk of extinction in this region.
For the Northeastern and Mediterranean population, while we found
that the best available information suggests that smooth hammerhead
sharks in the Mediterranean Sea have significantly declined, and
acknowledge that existing regulatory mechanisms may not be adequate to
prevent overutilization of the smooth hammerhead sharks specifically
when they occur in the Mediterranean, the same cannot be concluded for
those sharks when they occur in the Northeastern Atlantic. Available
hammerhead-specific information from the Northeastern Atlantic shows a
variable trend in the catch and abundance of hammerhead sharks over the
past decade, and without additional information on present abundance
levels, distribution information, or catch and overall utilization
rates of the smooth hammerhead shark, we found that the best available
information does not indicate that overutilization is a threat
significantly contributing to the species' risk of extinction in this
region. Additionally, as noted previously, the current regulations
managing the exploitation of the Northeastern and Mediterranean
population are not significantly different across international
governmental boundaries.
Given the above findings on the exploitation of the populations
identified by the petitioner, as well as the information on the other
ESA Section 4(a)(1) factors discussed previously in this finding, we do
not find that the petitioner's identified populations are delimited by
international governmental boundaries within which differences in
control of exploitation, management of habitat, conservation status,
and regulatory mechanisms exist that are significant in light of
Section 4(a)(1)(D) of the ESA.
As stated in the joint DPS policy, Congress expressed its
expectation that the Services would exercise authority with regard to
DPSs sparingly and only when the biological evidence indicates such
action is warranted. Based on our evaluation of the best available
scientific information, we do not find biological evidence to suggest
that any of the populations identified by the petitioner meet the
discreteness criterion of the DPS Policy. Because the identified
populations are not discrete from each other, we do not need to
determine whether the identified populations are significant to the
global taxon of smooth hammerhead sharks, per the DPS policy. As such,
we find that none of the population segments identified by the
petitioner qualify as a DPS under the DPS policy and, therefore, none
warrant listing under the ESA.
Similarity of Appearance Listing
The Defenders of Wildlife petition requested that we also consider
listing the smooth hammerhead shark as threatened or endangered based
on its similarity of appearance to the listed scalloped hammerhead
shark DPSs. Section 4 of the ESA (16 U.S.C. 1533(e)) provides that the
Secretary may treat any species as an endangered or threatened species
even though it is not listed pursuant to Section 4 of the ESA when the
following three conditions are satisfied: (1) Such species so closely
resembles in appearance, at the point in question, a species which has
been listed pursuant to such section that enforcement personnel would
have substantial difficulty in attempting to differentiate between the
listed and unlisted species; (2) the effect of this substantial
difficulty is an additional threat to an endangered or threatened
species; and (3) such treatment of an unlisted species will
substantially facilitate the enforcement and further the policy of this
chapter (16 U.S.C. 1533(e)(A)-(C)).
While we find that the smooth and scalloped hammerhead sharks do
closely resemble each other in appearance, we do not find that this
resemblance poses an additional threat to the listed scalloped
hammerhead shark, nor do we find that treating the smooth hammerhead
shark as an endangered or threatened species will substantially
facilitate the enforcement of current ESA prohibitions or further the
policy of the ESA. As described in the scalloped hammerhead shark final
rule (79 FR 38213; July 3, 2014) and critical habitat determination (80
FR 71774; November 17, 2015), the significant operative threats to the
listed scalloped hammerhead DPSs are overutilization by foreign
industrial, commercial, and artisanal fisheries and inadequate
regulatory mechanisms in foreign nations to protect these sharks from
the heavy fishing pressure and related mortality in waters outside of
U.S. jurisdiction. While three of the listed DPSs have portions of
their range within U.S. waters (i.e., the Central and Southwest
Atlantic DPS, Eastern Pacific DPS, and Indo-West Pacific DPS), the take
and trade of scalloped hammerhead sharks by persons under U.S.
jurisdiction were not identified as significant threats to the listed
DPSs. In fact, for the threatened scalloped hammerhead shark DPSs
(i.e., the Central and Southwest Atlantic DPS and Indo-West Pacific
DPS), we determined that prohibiting these activities would not have a
significant effect on the extinction risk of those DPSs (79 FR 38213;
July 3, 2014). [For the Eastern Pacific DPS, while take and trade of
this DPS by persons under U.S. jurisdiction were not identified as
significant threats, the take prohibitions of section 9(a)(1) of the
ESA (16 U.S.C. 1538(a)(1)) automatically apply because it is listed as
endangered under the ESA.] Overall, interaction with the listed
scalloped hammerhead shark DPSs by fishermen under U.S. jurisdiction is
negligible.
Additionally, the United States does not have a significant
presence in the international fin trade, with U.S. exports and imports
of all species of shark fins comprising less than 0.50 percent of the
total number of fins globally exported and imported (based on 2009-2013
data from U.S. Census Bureau, available at: http://www.st.nmfs.noaa.gov/commercial-fisheries/foreign-trade/index, and from
the FAO, available at: http://www.fao.org/fishery/statistics/global-commodities-production/en). As such, it was determined that any
conservation actions for the listed scalloped hammerhead shark DPSs
that would bring these DPSs to the point that the measures of the ESA
are no longer necessary will need to be implemented by foreign nations.
In terms of the impact of fishing pressure on the listed scalloped
hammerhead shark DPSs by U.S. fishermen, as the final rule details,
this additional mortality is not viewed as contributing significantly
to the identified threats of overutilization and inadequate regulatory
measures to the listed DPSs (79 FR 38213; July 3, 2014). This is
primarily a result of the negligible interaction between U.S.
[[Page 41957]]
fishermen and the listed scalloped hammerhead shark DPSs, with the
listed DPSs rarely caught by persons under U.S. jurisdiction (Miller et
al. 2014a). Furthermore, current U.S. fishery regulations prohibiting
the landing of scalloped hammerhead sharks also prohibit the landing of
smooth hammerhead sharks. For example, in the Atlantic Ocean, including
the Caribbean Sea, Atlantic HMS commercially-permitted vessels that
have pelagic longline gear on board, and dealers buying from these
vessels, have been prohibited from retaining onboard, transshipping,
landing, storing, selling, or offering for sale any part or whole
carcass of hammerhead sharks of the family Sphyrnidae (except for the
S. tiburo) (76 FR 53652; August 29, 2011). As such, there is unlikely
to be any enforcement issue requiring officials to distinguish between,
for example, endangered Eastern Atlantic DPS of scalloped hammerhead
sharks and smooth hammerhead sharks as both species are prohibited from
being landed.
In the Pacific, the core range of the endangered Eastern Pacific
DPS is outside of U.S. jurisdiction (80 FR 71774; November 17, 2015).
Based on the information from the scalloped hammerhead shark status
review (Miller et al. 2014a), catch of this DPS by U.S. fishermen is
extremely rare. In fact, observer data collected from 1993 to 2015
indicate that no scalloped hammerhead sharks have been observed caught
by large U.S. purse seine vessels (>363 mt capacity) operating in the
Eastern Pacific Ocean since 2006 (C. Barroso, Fishery Policy Analyst,
personal communication 2016). Furthermore, the U.S. States and
territories located in the Pacific have passed laws addressing the
possession, sale, trade, or distribution of shark fins, which will
further discourage landing of scalloped hammerhead sharks. These U.S.
states and territories (and year that law was passed) include Hawaii
(2010), California (2011), Oregon (2011), Washington (2011), the
Commonwealth of the Northern Mariana Islands (2011), Guam (2011), and
American Samoa (2012). As such, it is unlikely that U.S. fishermen will
be landing hammerhead species in the United States if their fins cannot
be traded. Hence, we do not foresee enforcement difficulties related to
distinguishing between hammerhead species. As an additional note, the
states of Illinois (2012), Maryland (2013), Delaware (2013), New York
(2013), and Massachusetts (2014) have also passed similar laws
prohibiting the possession, sale, trade, or distribution of shark fins.
With the passage of the U.S. Shark Conservation Act (Pub. L. 111-
348, Jan. 4, 2011), except for smooth dogfish sharks (Mustelus canis),
it is also now illegal to ``remove any of the fins of a shark
(including the tail) at sea; to have custody, control, or possession of
any such fin aboard a fishing vessel unless it is naturally attached to
the corresponding carcass; to transfer any such fin from one vessel to
another vessel at sea, or to receive any such fin in such transfer,
without the fin naturally attached to the corresponding carcass; or to
land any such fin that is not naturally attached to the corresponding
carcass, or to land any shark carcass without such fins naturally
attached.'' As mentioned in the U.S. Shark finning report to Congress
(NMFS 2014a), these provisions have improved the ability of U.S.
enforcement personnel to enforce shark finning prohibitions in domestic
shark fisheries. These shark finning prohibitions also facilitate
enforcement of ESA prohibitions as any landed hammerhead shark will
have its fins attached to its corresponding carcass. As noted in the
NMFS Shark Fin ID Guide, while the first dorsal fins of the smooth and
scalloped hammerhead shark are ``almost indistinguishable,'' the
pectoral fins differ in coloration and can be ``easily identified''
(Abercrombie et al. 2013). Specifically, in scalloped hammerhead
sharks, the ventral surfaces of the pectoral fins have dark patches
concentrated at the apex whereas smooth hammerheads lack this dark
patch. Since these sharks must be landed with all their fins naturally
attached to the carcass, enforcement officials at U.S. ports can use
the differences in pectoral fin coloration to differentiate between the
species. If the cephalophoil (or head) of the hammerhead shark is also
left on the carcass, it provides an additional morphological
distinction that can be used to differentiate the species as the smooth
hammerhead shark lacks the central indentation that is found on the
scalloped hammerhead shark cephalophoil. Regardless, as previously
mentioned, there are no ESA take prohibitions for the threatened
scalloped hammerhead sharks found in U.S. waters in the Caribbean
(Central and Southwest Atlantic DPS) or western Pacific (Indo-West
Pacific DPS) and coupled with the other state and Federal fishery
regulations that have been implemented in U.S. Atlantic and Pacific
waters, it will largely be unnecessary for enforcement personnel to
differentiate between landed smooth and scalloped hammerhead sharks for
the furtherance of the ESA.
For the reasons above, we do not find it advisable to further
regulate the commerce or taking of the smooth hammerhead shark by
treating it as an endangered or threatened species based on similarity
of appearance to the listed scalloped hammerhead shark DPSs.
Final Determination
Section 4(b)(1) of the ESA requires that NMFS make listing
determinations based solely on the best scientific and commercial data
available after conducting a review of the status of the species and
taking into account those efforts, if any, being made by any state or
foreign nation, or political subdivisions thereof, to protect and
conserve the species. We have independently reviewed the best available
scientific and commercial information including the petition, public
comments submitted on the 90-day finding (80 FR 48053; August 11,
2015), the status review report (Miller 2016), and other published and
unpublished information, and have consulted with species experts and
individuals familiar with smooth hammerhead sharks. We considered each
of the statutory factors to determine whether it presented an
extinction risk to the species on its own, now or in the foreseeable
future, and also considered the combination of those factors to
determine whether they collectively contributed to the extinction risk
of the species, now or in the foreseeable future. As previously
explained, we could not identify any portion of the species' range that
met both criteria of the SPR policy. Additionally, we did not find
biological evidence that would indicate that the population segments
identified by the petitioner qualify as DPSs under the DPS policy.
Therefore, our determination set forth below is based on a synthesis
and integration of the foregoing information, factors and
considerations, and their effects on the status of the species
throughout its entire range.
Based on our consideration of the best available scientific and
commercial information, as summarized here and in Miller (2016), we
find that the smooth hammerhead shark faces an overall low risk of
extinction and conclude that the species is not currently in danger of
extinction throughout its range nor is it likely to become so within
the foreseeable future. Accordingly, the smooth hammerhead shark does
not meet the definition of a threatened or endangered species, and
thus, the smooth hammerhead shark does not
[[Page 41958]]
warrant listing as threatened or endangered at this time. This is a
final action, and, therefore, we do not solicit comments on it.
References
A complete list of all references cited herein is available upon
request (see FOR FURTHER INFORMATION CONTACT).
Authority
The authority for this action is the Endangered Species Act of
1973, as amended (16 U.S.C. 1531 et seq.).
Dated: June 20, 2016.
Samuel D. Rauch III,
Deputy Assistant Administrator for Regulatory Programs, National Marine
Fisheries Service.
[FR Doc. 2016-15200 Filed 6-27-16; 8:45 am]
BILLING CODE 3510-22-P