[Federal Register Volume 79, Number 112 (Wednesday, June 11, 2014)]
[Notices]
[Pages 33509-33526]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2014-13621]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[Docket No. 130213133-4463-02]
RIN 0648-XC508
Endangered and Threatened Wildlife and Plants; Notice of 12-Month
Finding on Petitions To List the Great Hammerhead Shark as Threatened
or Endangered Under the Endangered Species Act (ESA)
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.
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SUMMARY: We, NMFS, announce a 12-month finding on two petitions to list
the entire population of great hammerhead shark (Sphyrna mokarran), the
northwest Atlantic population, or any distinct population segments
(DPSs) of great hammerhead sharks, as threatened or endangered under
the Endangered Species Act (ESA). We have completed a comprehensive
status review of the great hammerhead shark in response to these
petitions. Based on the best scientific and commercial information
available, including the status review report (Miller et al., 2014), we
have determined that the species is not comprised of DPSs and does not
warrant listing at this time. We conclude that the great 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 11, 2014.
ADDRESSES: The status review document for the great hammerhead shark is
available electronically at: http://www.nmfs.noaa.gov/pr/species/fish/greathammerheadshark.htm. 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: Great Hammerhead Shark 12-
month Finding.
FOR FURTHER INFORMATION CONTACT: Maggie Miller, NMFS, Office of
Protected Resources, (301) 427-8403.
SUPPLEMENTARY INFORMATION:
Background
On December 21, 2012, we received a petition from WildEarth
Guardians (WEG) to list the great hammerhead shark (Sphyrna mokarran)
as threatened
[[Page 33510]]
or endangered under the ESA throughout its entire range, or, as an
alternative, to list any identified DPSs as threatened or endangered.
The petitioners also requested that critical habitat be designated for
the great hammerhead under the ESA. On March 19, 2013, we received a
second petition from Natural Resources Defense Council (NRDC) to list
the northwest Atlantic DPS of great hammerhead shark as threatened, or,
as an alternative, to list the great hammerhead shark range-wide as
threatened, and to designate critical habitat. On April 26, 2013, we
published a positive 90-day finding (78 FR 24701), announcing that the
petitions 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 great 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 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). The PECE provides direction for considering conservation efforts
that have not been implemented, or have been implemented but not yet
demonstrated effectiveness.
Status Review
We convened a team of agency scientists to conduct the status
review for the species and prepare a report. The status review report
of the great hammerhead shark (Miller et al., 2014) compiles the best
available information on the status of the great hammerhead shark as
required by the ESA, provides an evaluation of the discreteness and
significance of populations in terms of the DPS policy, and assesses
the current and future extinction risk for the great hammerhead shark,
focusing primarily on threats related to the five statutory factors set
forth above. We appointed a contractor in the Office of Protected
Resources Endangered Species Division to undertake a scientific review
of the life history and ecology, distribution, abundance, and threats
to the great hammerhead shark. Next, we convened a team of biologists
and shark experts (hereinafter referred to as the Extinction Risk
Analysis (ERA) team) to conduct an extinction risk analysis for the
great hammerhead shark, using the information in the scientific review.
The ERA team was comprised of a fishery management specialist from
NMFS' Highly Migratory Species Management Division, two research
fishery biologists from NMFS' Southeast Fisheries Science Center and
Pacific Island Fisheries Science Center, and a fishery biologist
contractor with NMFS' Office of Protected Resources. The ERA team had
group expertise in shark biology and ecology, population dynamics,
highly migratory species management, and stock assessment science. The
status review report presents the ERA team's professional judgment of
the extinction risk facing the great hammerhead shark but makes no
recommendation as to the listing status of the species. The status
review report is available electronically at http://www.nmfs.noaa.gov/pr/species/fish/greathammerheadshark.htm.
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 great
hammerhead sharks. The peer reviewers were asked to evaluate the
adequacy, appropriateness, and application of data used in the status
review as well to evaluate the findings made in the ``Assessment of
Extinction Risk'' section of the report. 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 great hammerhead
shark. Much of the information discussed below on great 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); our regulations
[[Page 33511]]
regarding listing determinations; and our DPS policy.
Life History, Biology, and Status 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 hammerhead
sharks belong to the Genus Sphyrna with one exception, the winghead
shark (E. blochii), which is the sole species in the Genus Eusphyra.
The hammerhead sharks are recognized by their laterally expanded head
that resembles a hammer, hence the common name ``hammerhead.'' The
great hammerhead shark (Sphyrna mokarran) is the largest of the
hammerhead shark species and is distinguished from other hammerhead
sharks by a nearly straight anterior margin of the head and median
indentation in the center in adults. The shark has strongly serrated
teeth, strongly falcate first dorsal and pelvic fins, and a high second
dorsal fin with a concave rear margin (Compagno, 1984; Bester, n.d.).
The body of the great hammerhead shark is fusiform, with the dorsal
side colored dark brown to light grey or olive that shades to white on
the ventral side (Compagno, 1984; Bester, n.d.). Fins of adult great
hammerhead sharks are uniform in color, whereas the tip of the second
dorsal fin of juveniles may appear dusky (Bester, n.d.).
Current Distribution
The great hammerhead shark is a circumtropical species that lives
in coastal-pelagic and semi-oceanic waters from latitudes of 40[deg] N
to 31[deg] S (Compagno, 1984; Stevens and Lyle, 1989; Cliff, 1995;
Denham et al., 2007). It occurs over continental shelves as well as
adjacent deep waters, and may also be found in coral reefs and lagoons
(Compagno, 1984; Denham et al., 2007; Bester, n.d.).
Movement and Habitat Use
Great hammerhead sharks are generally solitary and highly mobile
(Compagno, 1984; Cliff, 1995; Denham et al., 2007; Hammerschlag et al.,
2011; Bester, n.d.). In a review of shark tagging studies, Kohler and
Turner (2001) examined three studies that looked at migrations of great
hammerhead sharks (n = 220) and found maximum distance travelled to be
1,180 km and a maximum time at liberty of 4 years. A more recent study
tracked a great hammerhead shark migrating an even greater distance,
with a minimum distance of 1,200 km in 62 days, as it appeared to
follow the Gulf Stream Current from the Florida Keys to 500 km off the
coast of New Jersey (Hammerschlag et al., 2011). Some great hammerhead
shark populations are thought to make poleward migrations following
warm water currents, such as those found off Florida's coast (Heithaus
et al., 2007; Hammerschlag et al., 2011), while others are thought to
be residential populations with only seasonal incursions into cooler
waters due to range expansions (not true migrations) (Taniuchi, 1974;
Stevens and Lyle, 1989; Cliff, 1995).
Diet
The great hammerhead shark is a high trophic level predator
(trophic level = 4.3; Cort[eacute]s, 1999) and opportunistic feeder
with a diet that includes a wide variety of teleosts, cephalopods, and
crustaceans, with a preference for stingrays and other batoids
(Compagno, 1984; Strong et al., 1990; Denham et al., 2007). Sphyrna
mokarran has been observed to use its uniquely shaped head, or
`cephalofoil,' to pin down and prey upon stingrays. This type of prey
handling may be unique to this species, but very few observations of
predation events of great hammerhead sharks or other Sphyrnidae have
been made (Strong et al., 1990; Chapman and Gruber, 2002). Stomach
analysis of S. mokarran suggests that the species primarily feeds at or
near the seafloor (Stevens and Lyle, 1989; Cliff, 1995; Bester, n.d.).
Reproduction
Compared to the other hammerhead species, Sphyrna mokarran has a
faster growth rate and thus matures at an earlier age, between 5 and
8.9 years (Piercy et al., 2010; Harry et al., 2011a; Piercy and
Carlson, unpublished data). In terms of size, females attain maturity
generally around 210-300 cm total length (TL) while males reach
maturity at smaller sizes (generally around 187-269 cm TL) (see Table 1
in Miller et al., 2014). Female great hammerhead sharks are viviparous
(i.e., give birth to live young) with a yolk-sac placenta and breed
only once every 2 years (Stevens and Lyle, 1989), with a gestation
period of 10-11 months (Stevens and Lyle, 1989; Bester, n.d.). In terms
of size, females attain maturity generally around 210-230 cm (TL at 50
percent maturity--L50) while males reach maturity at smaller sizes (L50
estimated around 187-230 cm TL). Litter sizes range from 6 to 42 pups,
with size at birth estimated at 500-700 mm TL. Parturition occurs in
the late spring or summer in the northern hemisphere (Ebert and
Stehman, 2013). In the southern hemisphere, birthing occurs between
October and November off eastern Australia, and between December and
January off northern Australia (Stevens and Lyle, 1989; Harry et al.,
2011a). Although young of the year and juveniles may occasionally be
found utilizing shallow inshore and coastal waters, nursery areas have
yet to be identified for this species and it is thought that pupping
occurs farther offshore (Hueter and Tyminski, 2007; Harry et al.,
2011a).
Size and Growth
The great hammerhead shark can reach lengths of over 610 cm TL
(Compagno, 1984); however, individuals greater than 400 cm TL are rare
(Stevens and Lyle, 1989). Piercy et al. (2010) estimated the oldest
female and male great hammerhead sharks to be 44 and 42 years,
respectively, with corresponding lengths of 398 cm TL (female) and 379
cm TL (male). Passerotti et al. (2010) aged two male great hammerhead
sharks using bomb radiocarbon aging methods, and found the sharks to be
42 years old (corresponding to 391 cm TL) and 36 years old
(corresponding to 360 cm TL). Male great hammerhead sharks are thought
to grow faster than females (with a growth coefficient, k, of 0.16/year
for males and 0.11/year for females) but reach a smaller asymptotic
size (335 cm TL for males versus 389 cm TL for females). Using life
history parameters from the northwest Atlantic Ocean, Cort[eacute]s
(unpublished) estimated productivity of the great hammerhead shark,
determined as intrinsic rate of population increase (r), to be 0.096
year-1 (median) within a range of 0.078-0.116 (80 percent
percentiles).
Although there are very few age/growth studies for great hammerhead
sharks, the available data indicate that great hammerhead sharks are a
long-lived species (at least 20-30 years) and can be characterized as
having rather low productivity (based on the Food and Agriculture
Organization of the United Nations (FAO) productivity indices for
exploited fish species, where r < 0.14 is considered low productivity),
making them generally vulnerable to depletion and potentially slow to
recover from overexploitation.
Current Status
Great hammerhead sharks can be found worldwide, with no present
indication of a range contraction. Although rare and generally not
targeted, they may be caught in many global fisheries including bottom
and pelagic longline tuna and swordfish fisheries, purse seine
fisheries, coastal gillnet fisheries, and artisanal fisheries.
[[Page 33512]]
Due to their large fins with high fin needle content (a gelatinous
product used to make shark fin soup), they are valuable as incidental
catch for the international shark fin trade (Abercrombie et al., 2005;
Clarke et al., 2006a). To a much lesser extent, hammerhead sharks are
utilized for their meat, with Colombia, Japan, Kenya, Mexico,
Mozambique, Philippines, Seychelles, Spain, Sri Lanka, China (Taiwan),
Tanzania, Trinidad and Tobago, Uruguay, and Venezuela identified as
countries that consume hammerhead meat (Vannuccini, 1999; CITES, 2010;
F. Arocha, personal communication).
In 2007, the International Union for Conservation of Nature (IUCN)
considered the great hammerhead shark to be endangered globally, based
on an assessment by Denham et al. (2007) and its own criteria (A2bd and
4bd), and placed the species on its ``Red List.'' Under criteria A2bd
and 4bd, a species may be classified as endangered when its ``observed,
estimated, inferred or suspected'' population size is reduced by 50
percent or more over the last 10 years, any 10 year time period, or
three generation period, whichever is the longer, and where the causes
of reduction may not have ceased, be understood, or be reversible based
on an index of abundance appropriate to the taxon and/or the actual or
potential levels of exploitation. IUCN justification for the
categorization is based on suspected declines due to the lack of
available species-specific data. IUCN notes that the species
vulnerability to depletion, low survival at capture, high value for the
fin trade, regional recognition of declines, and absence of recent
records gives cause to suspect that the population has decreased by
over 50 percent and meets the criteria for Endangered globally. The
prior IUCN assessment of the species in 2000 categorized the great
hammerhead shark as ``data deficient.'' As a note, the IUCN
classification for the great hammerhead shark alone does not provide
the rationale for a listing recommendation under the ESA, but the
sources of information that the classification is based upon are
evaluated in light of the standards on extinction risk and impacts or
threats to the species.
Distinct Population Segment Analysis
As described above, 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.'' The ERA team was asked to evaluate whether
any population of great hammerhead shark qualifies as a DPS based on
the elements of discreteness and significance as defined in the DPS
policy. According to the ERA team, the best available information does
not indicate that any population segment of the great hammerhead shark
would qualify as a DPS under the DPS policy because there was no
population segment that met the policy's ``discreteness'' criterion.
There is very little available information regarding discreteness based
on genetic differences. The ERA team reviewed an abstract (Testerman
and Shivji, 2013) but was not provided access to any further
information or details regarding the results presented in the abstract
(due to pending publication for a student's thesis). Although the
abstract made mention of possible genetic partitioning between and
within oceanic basins, this was a general statement and no further
information was provided on the specific geographic patterns of this
genetic structure. Therefore, we could not use this abstract to
identify discrete great hammerhead populations based on genetic
differences. The ERA team also examined a study by Naylor et al. (2012)
that suggested that there are two distinct clusters of great hammerhead
sharks: One comprised of great hammerhead sharks from the Atlantic, and
a second comprised of great hammerhead sharks from Australia and
Borneo. However, as the ERA team points out, the analysis was based on
22 specimens from 4 locations, with only 6 of the samples collected
outside of the Atlantic Ocean (Naylor et al., 2012). Given that the
species has a global distribution and the sample size was small and
only from a limited number of locations, we agreed with the ERA team
that this does not provide sufficient evidence of discreteness based on
genetic differences. The ERA team also evaluated the information in the
petitions regarding DPSs but did not find evidence that would support
discreteness based on genetic, geographical, or regulatory differences
(Miller et al., 2014). We reviewed the ERA team's analysis and agree
with its findings.
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 that would
indicate that any population segment of the great hammerhead shark
would qualify as a DPS under the DPS policy.
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. We consider a
variety of information and apply professional judgment in evaluating
the level of risk faced by a species in deciding whether the species is
threatened or endangered. We evaluate both demographic risks, such as
low abundance and productivity, and threats to the species including
those related to the factors specified by the ESA Section 4(a)(1)(A)-
(E).
Methods
As we have explained, we convened an ERA team to evaluate
extinction risk to the species. This section discusses the methods used
to evaluate threats and the overall extinction risk to the species. As
explained further down in this notice, we have separately taken into
account other conservation efforts which have the potential to reduce
threats identified by the ERA team.
For purposes of the risk assessment, an ERA team comprised of
fishery biologists and shark experts was convened to review the best
available information on the species and evaluate the overall risk of
extinction facing the great hammerhead shark now and in the foreseeable
future. The term ``foreseeable future'' was defined as the timeframe
over which threats could be reliably predicted to impact the biological
status of the species. After considering the life history of the great
hammerhead shark, availability of data, and type of threats, the ERA
team decided that the foreseeable future should be defined as
approximately 3 generation times for the great hammerhead shark, or 50
years. (A generation time is defined as the time it takes, on average,
for a sexually mature female great hammerhead shark to be replaced by
offspring with the same spawning capacity). This timeframe (3
generation times) takes into account the time necessary to provide for
the conservation and recovery of the species. As a late-maturing
species, with slow growth rate and low productivity, it would likely
take more than a generation time for any conservative management action
to be realized and
[[Page 33513]]
reflected in population abundance indices.
In addition, the foreseeable future timeframe is also a function of
the reliability of available data regarding the identified threats and
extends only as far as the data allow for making reasonable predictions
about the species' response to those threats. Since the main threats to
the species were identified as fisheries and inadequacy of existing
regulatory measures that manage these fisheries, the ERA team felt that
they had the background knowledge in fisheries management and expertise
to confidently predict the impact of these threats on the biological
status of the species within this timeframe.
Often the ability to measure or document risk factors is limited,
and information is not quantitative or very often lacking altogether.
Therefore, in assessing risk, it is important to include both
qualitative and quantitative information. In previous NMFS status
reviews, Biological Review Teams and ERA teams have used a risk matrix
method to organize and summarize the professional judgment of a panel
of knowledgeable scientists. This approach is described in detail by
Wainright and Kope (1999) and has been used in Pacific salmonid status
reviews as well as in the status reviews of many other species (see
http://www.nmfs.noaa.gov/pr/species/ for links to these reviews). In
the risk matrix approach, the collective condition of individual
populations is summarized at the species level according to four
demographic risk criteria: Abundance, growth rate/productivity, spatial
structure/connectivity, and diversity. These viability criteria,
outlined in McElhany et al. (2000), reflect concepts that are well-
founded in conservation biology and that individually and collectively
provide strong indicators of extinction risk.
Using these concepts, the ERA team estimated demographic risks by
assigning a risk score to each of the four demographic criteria. The
scoring for the demographic risk criteria correspond to the following
values: 1--no or low risk, 2--moderate risk, and 3--high risk. Detailed
definitions of the risk scores can be found in the status review
report.
The ERA team also performed a threats assessment for the great
hammerhead shark by ranking the effect that the threat was currently
having on the extinction risk of the species. The levels ranged from
``no effect on extinction risk'' to ``significant effect'' and included
an ``unknown'' category for instances when there was not enough
information to determine the effect (if any) that the threat was having
on the species' extinction risk. The ERA team adopted the ``likelihood
point'' (FEMAT) method for ranking the threat effect levels to allow
individuals to express uncertainty. For this approach, each team member
distributed 10 `likelihood points' among the threat effect levels. This
approach has been used in previous NMFS status reviews (e.g., Pacific
salmon, Southern Resident killer whale, Puget Sound rockfish, Pacific
herring, and black abalone) to structure the team's thinking and
express levels of uncertainty when assigning risk categories. The
scores were then tallied (mode, median, range) and summarized for each
threat, and considered in making the overall risk determination.
Guided by the results from the demographics risk analysis as well
as the threats assessment, the ERA team members were asked to use their
informed professional judgment to make an overall extinction risk
determination for the great hammerhead shark now and in the foreseeable
future. For this analysis, the ERA team defined five levels of
extinction risk: 1--no or very low risk, 2--low risk, 3--moderate risk,
4--high risk, and 5--very high risk. Detailed definitions of these risk
levels can be found in the status review report. Again, the ERA team
adopted the FEMAT method, distributing 10 `likelihood points' among the
five levels of extinction risk. Although this process helps to
integrate and summarize a large amount of diverse information, there is
no simple way to translate the risk matrix scores directly into a
determination of overall extinction risk. Other descriptive statistics,
such as mean, variance, and standard deviation, were not calculated as
the ERA team felt these metrics would add artificial precision or
accuracy to the results. The scores were then tallied (mode, median,
range) and summarized.
Finally, the ERA team did not make recommendations as to whether
the species should be listed as threatened or endangered. Rather, the
ERA team drew scientific conclusions about the overall risk of
extinction faced by the great hammerhead shark under present conditions
and in the foreseeable future based on an evaluation of the species'
demographic risks and assessment of threats.
Evaluation of Demographic Risks
Abundance
There is currently a lack of reliable estimates of population size
for the great hammerhead shark, with most of the available information
indicating that the species is naturally low in abundance. Great
hammerhead sharks are rarely recorded in fisheries data but are thought
to have experienced possible localized population declines over the
past few decades (Dudley and Simpfendorder, 2006; Diop and Dossa, 2011;
Dia et al., 2012). Given the lack of data, however, the extent of the
decline and the current status of the global population are unclear.
Unlike the scalloped hammerhead shark stock in the northwest
Atlantic Ocean, we have not yet conducted (or accepted) a stock
assessment on the great hammerhead shark population. The ERA team
reviewed two species-specific stock assessments for the northwest
Atlantic population of great hammerhead sharks by Hayes (2008) and Jiao
et al. (2011), but found that these studies had high degrees of
uncertainty. Both assessments found significant catches in the early
1980s, over two orders of magnitude larger than the smallest catches,
but Hayes (2008) suggested that these large catches, which correspond
mostly to the NMFS Marine Recreational Fishery Statistics Survey
(MRFSS), are likely overestimated. Hayes (2008) also identified other
data deficiencies that added 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 U.S. pelagic longline fishery for the period
of 1982-1986. In terms of abundance trends, the Hayes (2008) stock
assessment found the models to have wide confidence intervals and be
highly sensitive to the inclusion or exclusion of relative abundance
indices, with depletion estimates ranging from 57 to 96 percent.
The Jiao et al. (2011) stock assessment, which used a more complex
Bayesian hierarchical surplus production model, examined the likelihood
of overfishing of the great hammerhead shark and found that after 2001,
the risk of overfishing of great hammerhead sharks was very low.
However, similar to the Hayes (2008) caveats, Jiao et al. (2011) warned
that the results should be viewed as illustrative rather than as
conclusive evidence of the present status of great hammerhead sharks.
Due to the significant uncertainty surrounding the results from these
stock assessment models, neither we, nor the ERA team, could
confidently draw conclusions regarding the demographic risk to the
[[Page 33514]]
great hammerhead shark from current abundance levels.
In addition to these stock assessment studies, the ERA team
examined more recent abundance data from the U.S. commercial bottom
longline (BLL) fishery, the NMFS Mississippi BLL survey, and the Mote
Marine Laboratory gillnet survey (see Miller et al., 2014). Using a
generalized linear modeling (GLM) approach, a relative abundance index
for great hammerhead sharks was derived using observer data (from 1994
to 2011) from the U.S. commercial BLL fishery operating in the Atlantic
Ocean and Gulf of Mexico (Carlson et al., 2012; Carlson, unpublished).
Trends in abundance indicated a nine percent increase over the length
of the time series. However, data from the NMFS Mississippi Laboratory
fishery independent BLL survey indicated no clear trend, likely owing
to the low number of observations in the data series (Adam Pollock,
personal communication). The abundance of juvenile great hammerhead
sharks captured in an inshore fishery independent survey conducted by
Mote Marine Laboratory from 1995 to 2004 showed a slight decline over
the time series.
In other areas of the great hammerhead shark range, specific
abundance data are absent, rare, or presented as a hammerhead complex.
Only one study, off the coast of South Africa, provided a substantial
time-series analysis of fishery-independent data specific to great
hammerhead sharks (Dudley and Simpfendorfer, 2006). The study, which
used data collected by the KwaZulu-Natal beach protection program,
showed that catch per unit effort (CPUE) of S. mokarran in beach
protection nets decreased by 90 percent from 1978 to 2003. Most of the
other scientific information that we and the ERA team reviewed
presented data on other species of hammerheads or the entire hammerhead
complex (see Miller et al., 2014). However, as the ERA notes, to use a
hammerhead complex or other hammerhead species as a proxy for great
hammerhead abundance is erroneous because of the large difference in
the proportions they make up in commercial and artisanal catch. Usually
great hammerhead sharks comprise < 10 percent of the sphyrnid catch
(Amorim et al., 1998; Castillo-Geniz et al., 1998; Rom[aacute]n
Verdesoto and Orozco-Z[ouml]ller, 2005; Dudley and Simpfendorfer, 2006;
White et al., 2008; Doukakis et al., 2011; Robinson and Sauer, 2011;
Dia et al., 2012). Although higher great hammerhead proportions have
been identified in a few other fisheries datasets (like the Venezuelan
longline fleet bycatch data--47 percent, Arocha et al., 2002; observed
U.S. BLL catch--32 percent from 1994-2011, Carlson, personal
communication; and Australia's observed Northern Territory Offshore Net
and Line bycatch--34 percent; Field et al., 2013), the majority of the
sphyrnid catch remains dominated by the scalloped hammerhead shark, a
hammerhead species whose greater abundance and schooling behavior makes
it more susceptible to being caught in large numbers by fishing gear.
Based on the very limited abundance information available, from
both fishery-independent and -dependent surveys, and its general rarity
in fisheries catch, the ERA team concluded that the great hammerhead
shark has likely declined from historical numbers as a result of
fishing mortality but is also naturally low in abundance. The ERA team
was concerned that the species' low abundance levels may pose a risk to
its continued existence if faced with other demographic risks or
threats. However, at present, there is no evidence to suggest that the
species is at a risk of extinction due to environmental variation,
anthropogenic perturbations, or depensatory processes based on its
current abundance levels.
Growth Rate/Productivity
Similar to abundance, the ERA team expressed some concern (through
its voting score of moderate risk) regarding the effect of the great
hammerhead shark's growth rate and productivity on its risk of
extinction. Sharks, in general, have lower reproductive and growth
rates compared to bony fishes; however, great hammerhead sharks exhibit
life-history traits and population parameters that are intermediary
among other shark species. Productivity, determined as intrinsic rate
of population increase, has been estimated at 0.096 per year (median)
within a range of 0.078-0.116 (80 percent percentiles) (Cort[eacute]s,
unpublished). These demographic parameters place great hammerhead
sharks towards the moderate to faster growing sharks along a ``fast-
slow'' continuum of population parameters that have been calculated for
38 species of sharks by Cort[eacute]s (2002, Appendix 2). However,
primarily based on the fact that most species of elasmobranchs take
many years to mature, and have relatively low fecundity compared to
teleosts, these life history characteristics could pose a risk to this
species in combination with threats that reduce its abundance.
Spatial Structure/Connectivity
The ERA team did not see habitat structure or connectivity as a
potential risk to this species. Habitat characteristics that are
important to this species are unknown, as are nursery areas. The sharks
inhabit a range of environments with varying complexity (from coral
reefs and lagoons to coastal waters over continental shelves and
adjacent deep waters). The species is also highly mobile (with tracked
distances of up to 1,200 km) with no data to suggest it is restricted
to any specific coastal area. There is no evidence of female philopatry
and there is little known about specific migration routes. As
previously mentioned, some great hammerhead shark populations are
thought to make poleward migrations following warm water currents
(Heithaus et al., 2007; Hammerschlag et al., 2011), while others are
thought to be residential populations (Taniuchi, 1974; Stevens and Lyle
1989; Cliff, 1995). It is also unknown if there are source-sink
dynamics at work that may affect population growth or species' decline.
Thus, there seems to be insufficient information that would support the
conclusion that spatial structure and connectivity pose significant
risks to this species. As such, the ERA team viewed these demographic
factors as having no or very low risk, meaning that they are unlikely
to pose a significant risk to the species' continued existence.
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. This species is found in a broad range of
habitats and appears 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. Based on
this information, the ERA team concluded, and we agree, that diversity
is unlikely to pose a significant risk to the species' continued
existence.
Summary of Factors Affecting the Great Hammerhead Shark
As described above, section 4(a)(1) of the ESA and NMFS
implementing regulations (50 CFR 424) 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
[[Page 33515]]
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 existence. The ERA team evaluated whether and the extent
to which each of the foregoing factors contributed to the overall
extinction risk of the global great hammerhead population. This section
briefly summarizes the ERA team's findings and our conclusions
regarding threats to the great hammerhead shark. More details can be
found in the status review report (Miller et al., 2014).
The Present or Threatened Destruction, Modification, or Curtailment of
Its Habitat or Range
The ERA team evaluated habitat destruction as a potential threat to
the great hammerhead shark, but did not find evidence to suggest that
it is presently contributing significantly to its risk of extinction.
Currently, great hammerhead sharks are found worldwide, residing in
coastal warm temperate and tropical seas, from latitudes of 40[deg] N
to 31[deg] S (Compagno, 1984; Stevens and Lyle, 1989; Cliff, 1995;
Denham et al., 2007). They occur over continental shelves as well as
adjacent deep waters, and may also be found in coral reefs and lagoons
(Compagno, 1984; Denham et al., 2007; Bester, n.d.). Great hammerhead
sharks appear to prefer water temperatures above 20[deg] C (Cliff,
1995; Taniuchi, 1974; Hueter and Manire, 1994); however, little else is
known regarding specific habitat preferences or characteristics.
In the U.S. exclusive economic zone (EEZ), the Magnuson-Stevens
Fishery Conservation and Management Act (MSA) requires NMFS to identify
and describe essential fish habitat (EFH) in fishery management plans
(FMPs), minimize the adverse effects of fishing on EFH, and identify
actions to encourage the conservation and enhancement of EFH. Towards
that end, NMFS has funded two cooperative survey programs intended to
help delineate shark nursery habitats in the Atlantic and Gulf of
Mexico. The Cooperative Atlantic States Shark Pupping and Nursery
Survey and the Cooperative Gulf of Mexico States Shark Pupping and
Nursery Survey are designed to assess the geographical and seasonal
extent of shark nursery habitat, determine which shark species use
these areas, and gauge the relative importance of these coastal
habitats for use in EFH determinations. Results from the surveys
indicate the importance of coastal waters off the Atlantic east coast,
from New Jersey to the Florida Keys and eastern Puerto Rico, throughout
the west coast of Florida, and scattered in the Gulf of Mexico from
Alabama to Texas (NMFS, 2009). As a side note, insufficient data are
available to differentiate EFH by size classes for the great hammerhead
shark; therefore, EFH is the same for all life stages. Since the great
hammerhead shark EFH is defined as the water column or attributes of
the water column, NMFS determined that there are minimal or no
cumulative anticipated impacts to the EFH from gear used in U.S. Highly
Migratory Species (HMS) and non-HMS fisheries, basing its finding on an
examination of published literature and anecdotal evidence (NMFS,
2006).
Likewise, great hammerhead shark habitat in other parts of its
range is assumed to be similar to that in the northwest Atlantic and
Gulf of Mexico, comprised of open ocean environments occurring over
broad geographic ranges and characterized primarily by the water column
attributes. As such, 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. The threat of global
climate change was investigated specifically for great hammerhead
sharks on Australia's Great Barrier Reef (GBR). Chin et al. (2010)
conducted an integrated risk assessment for climate change to assess
the vulnerability of great hammerhead sharks, as well as a number of
other chondrichthyan species, to climate change on the GBR. The
assessment examined individual species but also lumped species together
in ecological groups (such as freshwater and estuarine, coastal and
inshore, reef, shelf, etc.) to determine which groups may be most
vulnerable to climate change. The assessment took into account the in
situ changes and effects that are predicted to occur over the next 100
years in the GBR and assessed each species' exposure, sensitivity, and
adaptive capacity to a number of climate change factors including:
water and air temperature, ocean acidification, freshwater input, ocean
circulation, sea level rise, severe weather, light, and ultraviolet
radiation. Of the 133 GBR shark and ray species, the assessment
identified 30 as being moderately or highly vulnerable to climate
change. The great hammerhead shark, however, was not one of these
species. In fact, the great hammerhead shark was ranked as having a low
overall vulnerability to climate change, with low vulnerability to each
of the assessed climate change factors.
Additionally, the great hammerhead shark is highly mobile
throughout its range. Although there is very little information on
habitat use, and little is known about pupping and nursery areas, there
is no evidence to suggest its access to suitable habitat is restricted.
The species does not participate in natal homing, which would
essentially restrict the species to specific nursery grounds, and based
on a comparison of S. mokarran distribution maps from 1984 (Compagno,
1984) and 2014 (IUCN, 2014), the range of the great hammerhead shark
has not contracted.
Overall, the ERA team concluded that the effect that habitat
destruction, modification, or curtailment is having on the species'
extinction risk cannot be determined at this time, acknowledging that
while habitat specificity is not well defined for the species, there
may be other natural and anthropogenic impacts to the environment that
could have some effect on its pelagic habitat. Based on the best
available information, we conclude that the current evidence does not
indicate that there exists a present or threatened destruction,
modification, or curtailment of the great hammerhead shark's habitat or
range.
Overutilization for Commercial, Recreational, Scientific or Educational
Purposes
The ERA team identified overutilization for commercial and/or
recreational purposes as a threat with a moderate effect on the
extinction risk of the species, which means it is likely increasing the
species' extinction risk but only in combination with other threats or
factors.
Great hammerhead sharks are caught in many global fisheries
including bottom and pelagic longline fisheries, purse seine fisheries,
coastal gillnet fisheries, and artisanal fisheries. As a primarily warm
water species, the great hammerhead shark is most often seen in the
catches of tropical fisheries (Dudley and Simpfendorfer, 2006; Zeeberg
et al., 2006). It is generally not a target species, but due to its
large fins, it is valuable as incidental catch for the international
shark fin trade (Abercrombie et al., 2005; Clarke et al., 2006a).
There is very little information on the historical abundance,
catch, and trends of great hammerhead sharks, with only occasional
mentions in fisheries records. Although more countries and regional
fisheries management organizations (RFMOs) are working towards better
reporting of fish catches down to species level, catches of great
hammerheads have gone and continue
[[Page 33516]]
to go unrecorded in many countries outside the United States. Also,
many catch records that do include hammerhead sharks do not
differentiate between the Sphyrna species or shark species in general.
These numbers are also likely under-reported in catch records, as many
records do not account for discards (example: where the fins are kept
but the carcass is discarded) or reflect dressed weights instead of
live weights. Thus, the lack of catch data for great hammerhead sharks
makes it difficult to estimate rates of fishing mortality or conduct
detailed quantitative analyses of the effects of fishing on the great
hammerhead populations.
In the Northwest Atlantic, where some species-specific fisheries
data are available, the great hammerhead population size has appeared
to decline, likely due to historical overfishing of the species (see
Abundance section; Hayes (2008), Jiao et al. (2011)). However, since
2005 (the last year of the fisheries data from the Jiao et al. (2011)
and Hayes (2008) stock assessments), the trend is unclear, with some
evidence that the population may be stable or increasing (Carlson et
al., 2012; Carlson, unpublished). In addition, the ERA team voiced
concerns about the accuracy of species identification in historical
fisheries data. Hayes (2008) notes that the relative proportion of
great hammerhead sharks in the hammerhead catch has changed
significantly since the early 1980s, decreasing from around 50 percent
in 1982 to < 30 percent in 2005; however, the ERA team noted that
species identification for hammerhead sharks in landings data prior to
2007 was highly inaccurate, and does not believe these percentages are
valid. (Since January 1, 2007, the HMS Management Division has required
all U.S. Atlantic pelagic longline, bottom longline, and gillnet vessel
owners who hold shark permits and operators of those vessels to attend
a Protected Species Safe Handling, Release, and Identification
Workshop; and all Federally permitted shark dealers are required to
attend Atlantic Shark Identification workshops.) Hayes (2008) also
identifies many data deficiencies that have increased the uncertainty
in his estimates, including the misreporting of the species,
particularly in recreational fisheries, which has likely led to
overestimations of catches. In other studies that discriminate between
hammerhead species, great hammerheads tend to comprise < 10 percent of
the total hammerhead complex (see Abundance section of this notice).
Only recently has identification of sharks, down to species level,
become a priority for national and international fishery managers
(including many RFMOs), with the publication of shark and fin guides
available for fishermen in order to more accurately report shark
catches down to the species level.
The threat of overutilization in other areas of the great
hammerhead shark's range was also difficult to assess due to the lack
of available fisheries survey and catch data. For example, in Central
America and the Caribbean, many reports of the overfishing of
hammerhead sharks and subsequent declines are based on personal
observations and do not distinguish between hammerhead shark species
(Denham et al., 2007). One of the few datasets that provides specific
catches of great hammerhead sharks is the Venezuelan Pelagic Longline
Observer Program. Off Venezuela, observers note that great hammerhead
sharks are mostly concentrated around the oceanic islands and near the
edge of the continental shelf (Tavares and Arocha, 2008). In observed
catches of the Venezuelan longline fleet from 1994 to 2003, great
hammerhead sharks were the 4th most common species. Over the time
series, CPUE for the species declined and ranged between 8.70 sharks/
1000 hooks and 1.33 sharks/1000 hooks, with an average of 2.9 ( 1.58) sharks/1000 hooks; however, the decline in CPUE was not
statistically significant (Tavares and Arocha, 2008).
In the Southwest Atlantic, annual landings of hammerhead sharks
have fluctuated over the years. In the ports of Rio Grande and Itajai,
Brazil, reported landings in 1992 were ~ 30 mt but increased rapidly to
700 mt in 1994. From 1995 to 2002, catches decreased and fluctuated
between 100 and 300 mt (Baum et al., 2007). Information from surface
longline and bottom gillnet fisheries targeting hammerhead sharks off
southern Brazil indicates declines of more than 80 percent in CPUE from
2000 to 2008, with the targeted hammerhead fishery abandoned after 2008
due to the rarity of the species (FAO, 2010). However, when the
fisheries data identify the hammerhead sharks down to species, it
appears that great hammerhead sharks are seldom caught in this area.
For example, in a study on the removal of shark species by S[atilde]o
Paulo State tuna longliners off the coast of Brazil, Amorim et al.
(1998) documented significant catches of smooth and scalloped
hammerhead sharks from 1974-1997 (mainly on the southern continental
slope). However, great hammerhead sharks were only very rarely caught
by these Santos, S[atilde]o Paulo longliners, and represented <= 5
percent of the hammerhead species catch. In a follow up study,
conducted from 2007-2008, Amorim et al. (2011) found no records of S.
mokarran in the S[atilde]o Paulo State surface longline data, although
376 smooth and scalloped hammerhead sharks were recorded as caught.
In the Eastern Atlantic, great hammerhead sharks can be found off
the coast of West Africa. They were once documented ranging from
Mauritania to Angola, with periods of high abundance observed in
October in waters off Mauritania, and from November to January in
waters off Senegal (Cadenat and Blache, 1981). However, with the
targeted exploitation of shark species, especially in the Senegalese
and Gambian fisheries, there has been a significant and ongoing
decrease in shark landings in these waters. According to Diop and Dossa
(2011), shark fishing has occurred in the Sub Regional Fisheries
Commission (SRFC) member countries (Cape-Verde, Gambia, Guinea, Guinea-
Bissau, Mauritania, Senegal, and Sierra Leone) for around 30 years.
Shark fisheries and trade in this region first originated in Gambia,
but soon spread throughout the region in the 1980s and 1990s, as the
development and demand from the worldwide fin market increased. From
1994 to 2005, shark catch reached maximum levels, with a continued
increase in the number of boats, better fishing gear, and more people
entering the fishery, especially in the artisanal fishing sector.
Before 1989, artisanal catch was less than 4,000 mt (Diop and Dossa,
2011). However, from 1990 to 2005, catch increased dramatically from
5,000 mt to over 26,000 mt, as did the level of fishing effort (Diop
and Dossa, 2011). Including estimates of bycatch from the industrial
fishing fleet brings this number over 30,000 mt in 2005 (however,
discards of shark carcasses at sea were not included in bycatch
estimates, suggesting bycatch may be underestimated) (Diop and Dossa,
2011). In the SRFC region, an industry focused on the fishing
activities, processing, and sale of shark products became well
established. However, since 2005, there has been a continual decrease
in shark landings, with an observed extirpation of some species, and a
scarcity of others, such as large hammerhead sharks (Diop and Dossa,
2011), indicating overutilization of the resource. From 2005 to 2008,
shark landings dropped by more than 50 percent (Diop and Dossa, 2011).
In terms of hammerhead-specific information, the majority of data
is attributed to hammerhead sharks in general or scalloped hammerhead
[[Page 33517]]
sharks in particular. According to Senegal's annual fisheries reports,
hammerhead shark landings have decreased by more than 50 percent from
2006 to 2010. Dia et al. (2012) provide data from landings and
scientific surveys conducted in Mauritanian waters that show CPUE and
yields of scalloped hammerhead sharks fluctuating over the years, but
since 2006, showing a downward trend (with a note that the trend is the
same for great hammerhead sharks). In 2009, the total catch of sharks
in Mauritanian waters was 2,010 mt, with great hammerheads constituting
1.15 percent of the shark catch (or 23 mt) (Dia et al., 2012).
There are also reports of juvenile scalloped hammerhead sharks
being caught in large quantities by artisanal fishermen using driftnets
and fixed gillnets in this region (CITES, 2010); however, similar
reports for great hammerheads are absent. This is likely due to the
more solitary nature of the species, making it less susceptible to be
caught in large numbers. In addition, great hammerhead shark nursery
grounds are currently unknown so the extent of overutilization on
neonates and juveniles, which could affect recruitment success, appears
to be minimal.
In an effort to evaluate the vulnerability of specific shark stocks
to pelagic longline fisheries in the Atlantic Ocean, Cort[eacute]s et
al. (2012) conducted an Ecological Risk Assessment using observer
information collected from a number of fleets operating under the
International Commission for the Conservation of Atlantic Tunas
(ICCAT--which is the RFMO responsible for the conservation of tunas and
tuna-like species in the Atlantic Ocean and its adjacent seas).
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 or
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; Kiska, 2012).
Productivity and susceptibility scores are normally plotted on an x-y
scatter plot and an overall vulnerability or risk score is calculated
as the Euclidean distance from the origin of x-y scatter plot. For
example, a species with low productivity and high susceptibility would
be at a high risk to overexploitation by the fishery. In this way,
vulnerability scores can be ranked and compared between species.
Ecological Risk Assessment models are useful because they can be
conducted on a qualitative, semi-quantitative, or quantitative level,
depending on the type of data available for input.
Results from the Cort[eacute]s et al. (2012) Ecological Risk
Assessment indicate that great hammerhead sharks face a relatively low
risk in ICCAT fisheries. Out of the 20 assessed shark stocks, great
hammerhead sharks ranked 14th in terms of their susceptibility to
pelagic longline fisheries in the Atlantic Ocean. The population's
estimated productivity value (r = 0.070) ranked 10th; however, this was
based on older life history information and recent data suggest great
hammerhead sharks are more productive. Overall vulnerability ranking
scores (using three different calculation methods, and ranked on a
scale of 1 to 20 where 1 = highest risk) ranged from 10 to 14,
indicating that great hammerhead sharks have moderately low
vulnerability and face a relatively low risk to overexploitation by
ICCAT pelagic longline fisheries (Cort[eacute]s et al., 2012).
In the Indian Ocean, there are currently no quantitative stock
assessments or basic fishery indicators available for great hammerhead
sharks, and thus the level of great hammerhead shark utilization is
highly uncertain. Results from an Ecological Risk Assessment that
examined the impact of artisanal fisheries of the Southwest Indian
Ocean on mammals, sea turtles, and elasmobranchs indicate that
scalloped and great hammerhead sharks face a high risk (most
vulnerable) in drift gillnet fisheries (based on their low productivity
scores and high susceptibility scores) and a more moderate risk in
bottom set gillnets, beach seines and handlines (Kiszka, 2012).
Although great hammerhead sharks may be at greater risk from
overexploitation by coastal artisanal fisheries, the available data do
not show extensive utilization of this species by these fisheries. For
example, data from artisanal fisheries operating off Madagascar show
that S. mokarran are rarely caught. These artisanal fisheries are known
for targeting sharks primarily for their fins, fishing in shallow
waters with little regulation. Of the Sphyrnidae landings from these
fisheries, S. lewini is the most commonly represented species,
comprising more than 96 percent of the hammerhead shark landings
(Doukakis et al., 2011; Robinson and Sauer, 2011). Although these
artisanal fisheries are largely unregulated and motivated by the fin
trade, which increases the likelihood of overutilization of hammerhead
species, the fact that great hammerhead sharks are extremely rare in
the artisanal catch and landings data indicates that the minimal
utilization of the species by these fisheries is not likely to
significantly contribute to the species' risk of extinction.
In Australian waters, much of the data are not identified down to
hammerhead species. According to Heupel and McAuley (2007), significant
reductions in hammerhead catches in the `northern shark fisheries' (the
state-managed Western Australia North Coast Shark Fishery (WANCSF) and
the Joint Authority Northern Shark Fishery (JANSF)) occurred between
1996 and 2005. The northern shark fisheries have targeted a variety of
species including sandbar, blacktip, and lemon sharks, and historically
used demersal longline gear and pelagic gillnetting in the JANSF. Based
on an analysis of the CPUE data from 1996-2005, Hepuel and McAuley
(2007) suggest declines of 58 to 76 percent in hammerhead abundance in
Australia's northwest marine region. Although hammerhead sharks were
never targeted in this fishery, they were retained, but it is unclear
what proportion of this hammerhead catch was S. mokarran. In addition,
although the data suggest that hammerhead population abundance has
declined since the late 1990s, recent management measures and
regulations have essentially halted operations in this fishery (see The
Inadequacy of Existing Regulatory Mechanisms section below), thereby
greatly minimizing the threat of overutilization that this fishery
poses to the population when in this region.
The Australian Northern Territory Offshore Net and Line (NTONL)
fishery, which targets blacktip sharks and grey mackerels, operates off
the coastline of Australia's Northern Territory and uses longlines or
pelagic set nets (bottom set nets are prohibited). Other shark species,
including hammerhead sharks, are recorded as bycatch. Based on NTONL
observer data from 2002 to 2007 (during 49 days at sea), great
hammerhead sharks constituted 1.6 percent of the total catch of
elasmobranch species (Field et al., 2013). Their relative abundance was
calculated at 1.51 individuals per day (Field et al., 2013). In 2011,
hammerhead sharks constituted 12 percent of the total bycatch (141 mt),
exceeding the trigger reference point established for byproduct
species. Because of this, the management advisory committee for the
fishery will review the trigger breach and provide advice to the
Executive Director of Fisheries for necessary action (Northern
Territory Government, 2012). It is
[[Page 33518]]
unclear how many great hammerhead sharks were caught as the estimates
were for all Sphyrna spp. However, based on the observer data (Field et
al., 2013), the ratio of scalloped hammerheads to great hammerheads in
the bycatch is approximately 1.8:1.
Information on hammerhead shark utilization in the Western Pacific
is also mainly available from Australian fisheries operating in these
waters. Hammerhead sharks are specifically caught in a number of
fisheries operating off the eastern coast of Australia, including the
New South Wales Ocean Trap & Line fishery, the East Coast Tuna and
Billfish Fishery as well as the West Coast Tuna and Billfish Fishery.
Fisheries-independent data from protective shark meshing programs in
this region were assessed by the ERA team in an attempt to extract
additional temporal patterns of great hammerhead catch. From the
Queensland Shark Control Program (QSCP) dataset, the ERA team
reconstructed estimates of the great hammerhead shark catch for the
time period of 1985 to 1996. The results show a decline in great
hammerhead shark catch during the 1980s and 1990s followed by an
apparent increase over the more recent decade; however, in general,
great hammerhead sharks are relatively rare in both the reconstructed
results and the raw data (fewer than 35 individual sharks caught per
year). The ERA team also notes that this is a pattern of catch only,
and not a measure of abundance such as CPUE; however, based on the very
few historical and current catches, which supports the assumption of a
naturally rarely occurring species, and evidence of a recent increase
in beach net captures, it does not appear that the great hammerhead
shark population is at the point where depensatory processes are
placing it at an increased risk of extinction.
Similarly, data from a 3-year observer survey of small-scale
commercial gillnet vessels in the East Coast Inshore Finfish Fishery
(which operates in the Great Barrier Reef World Heritage Area off
Queensland) also suggests that S. mokarran are not commonly caught in
the inshore coastal areas of this region. Out of the total number of
elasmobranchs observed in the gillnet catch (n = 6,828), great
hammerhead sharks comprised only 1.5 percent of the catch (n = 102)
(Harry et al., 2011b). This is in contrast to the scalloped hammerhead
shark, which is likely the most abundant hammerhead species off the
coast of Queensland (Taylor et al., 2011), and was the 4th most
abundant elasmobranch in the gillnet catch (making up 8.8 percent of
the total catch, n = 604) (Harry et al., 2011b).
In the tropical waters of the Pacific, there are very limited data
available on the threat of overutilization of great hammerhead sharks
by fisheries operating in this region. One study that examined
operational-level logsheet and observer data of fleets operating in the
Republic of the Marshall Islands EEZ found only three reports of
observed S. mokarran individuals from 2005-2009 (although estimates of
total annual longline catches of sharks ranged from 1,583 to 2,274 mt/
year) (Bromhead et al., 2012). Again, the rarity of the species in
observer and catch data does not necessarily indicate overutilization
of the species, but rather may likely be a product of the species'
naturally low and diffuse abundance, infrequent occurrence in common
fishing grounds, and low susceptibility to certain fisheries.
Based on the information from the Eastern Pacific, the extent of
utilization of great hammerhead sharks is also very minimal. While S.
lewini has been documented as an important shark species that was
routinely caught off the Pacific coast of Mexico and in the Gulf of
California, with studies that have shown its importance in artisanal
fisheries (P[eacute]rez-Jim[eacute]nez et al., 2005; Bizzarro et al.,
2009; Smith et al., 2009), reports of S. mokarran in the fisheries data
are extremely rare. For example, in the Gulf of Tehuantepec, S. lewini
is the second most important species in the shark fishery, comprising
around 29 percent of the total shark catch from this area, whereas S.
mokarran is ranked 11th (out of 21 species) and comprises < 4.7 percent
of the catch (when grouped with other shark species) (INP, 2006).
Similarly, in studies off Costa Rica and Ecuador, records of great
hammerhead sharks in fisheries data are very rare, whereas S. lewini
and other hammerhead shark species are documented in observer and catch
data (Whoriskey et al., 2011).
The ERA team also assessed whether the shark fin trade could be a
threat driving overutilization of the great hammerhead shark. Based on
Hong Kong fin trade auction data from 1999--2001 and species-specific
fin weights and genetic information, Clarke et al. (2006b) estimated
that around 375,000 great hammerhead sharks (range: 130,000 to 1.1
million), with an equivalent biomass of around 21,000 mt, are traded
annually. Great hammerhead sharks comprised approximately 1.5 percent
of the total fins traded annually in the Hong Kong market (Clarke et
al., 2006a). The lack of estimates of the global, or even regional,
population makes it difficult to put these numbers into perspective. As
a result, the effect at this time of the removals (for the shark fin
trade) on the ability of the overall population to survive is unknown.
Overall, the ERA team concluded that overutilization in combination
with other factors, such as demographic risks, is likely increasing the
species' risk of extinction. However, due to the paucity of available
data, the ERA team expressed its uncertainty in assessing the
contribution of the threat of overutilization to the extinction risk of
the great hammerhead shark by placing 23 percent of its votes in the
``unknown'' risk level and distributing votes over a large range of
effect levels, from ``no effect'' to ``significant effect.'' As results
from the Cort[eacute]s et al. (2012) Ecological Risk Assessment
demonstrated, the threat of overutilization of great hammerhead sharks
may be tempered by the species' relatively low vulnerability to certain
fisheries, a likely condition of them having diffuse and naturally low
abundance, wide range, and rare presence on common fishing grounds.
Given the above analysis and best available information, we do not find
evidence that overutilization, by itself, is a threat that is currently
placing the species at an increased risk of extinction. The severity of
the threat of overutilization is dependent upon other risks and threats
to the species, such as its abundance (as a demographic risk) as well
as its level of protection from fishing mortality throughout its range;
but, at this time, there is no evidence to suggest the species is at or
near a level of abundance that places its current or future persistence
in question due to overutilization.
Disease or Predation
The ERA team evaluated disease and predation as potential threats
to the great hammerhead shark, but did not find evidence to suggest
that either is presently contributing significantly to its risk of
extinction. In terms of disease, the ERA team noted that since the
species prefers benthic prey (example: sting rays), it might be
susceptible to contaminants that accumulate on the sea floor.
Hammerhead sharks may accumulate brevotoxins, heavy metals, and
polychlorinated biphenyls in their liver, gill, and muscle tissues;
however, the lethal concentration limit of these toxins and metals is
currently unknown (Lyle, 1984; Storelli et al., 2003; Flewelling et
al., 2010). It is hypothesized that these apex predators can handle
higher body burdens of these anthropogenic toxins due to the large
[[Page 33519]]
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 (and prevalence) of toxin and metal
bioaccumulation in great hammerhead shark populations is unknown.
Great hammerhead sharks also likely carry a range of parasites,
such as external copepods (Alebion carchariae, A. elegans, Nesippus
crypturus, N. orientalis, Eudactylina pollex, Kroyerina gemursa, and
Nemesis atlantic)(Bester, n.d.); however, no data exist to suggest
these parasites are affecting S. mokarran abundance.
Predation is also not thought to be a factor influencing great
hammerhead abundance numbers. The most significant predator on great
hammerhead sharks is likely humans, although larger sharks, including
adult S. mokarran, are known to prey upon injured or smaller great
hammerheads. However, the extent of predation of juveniles in nursery
areas is currently unknown. In addition, because great hammerhead
sharks are apex predators and opportunistic feeders, with a diet
composed of a wide variety of items, including teleosts, cephalopods,
crustaceans, and rays (Compagno, 1984; Bester, n.d.), it is unlikely
that they are threatened by competition for food sources. Although
there may be some prey species that have experienced population
declines, no information exists to indicate that depressed populations
of these prey species are negatively affecting great hammerhead shark
abundance.
Therefore, based on the best available information, the ERA team
concluded, and we agree, that neither disease nor predation is
increasing the species' extinction risk.
The Inadequacy of Existing Regulatory Mechanisms
The ERA team evaluated existing regulatory mechanisms to determine
whether they may be inadequate to address threats to the great
hammerhead shark. Existing regulatory mechanisms may include Federal,
state, and international regulations. Below is a brief description and
evaluation of current and relevant domestic and international
management measures that affect the great hammerhead shark. More
information on these domestic and international management measures can
be found in the status review report (Miller et al., 2014).
In the northwest Atlantic, the U.S. Atlantic HMS Management
Division within NMFS (HMS Management Division) develops regulations for
Atlantic HMS fisheries, and primarily coordinates the management of
Atlantic HMS fisheries in Federal waters (domestic) and the high seas
(international), while individual states establish regulations for HMS
in state waters. The NMFS Atlantic HMS Management Division currently
manages 39 species of sharks (excluding spiny dogfish, which is managed
jointly by the New England and Mid-Atlantic Fishery Management
Councils, and smooth dogfish, which will be managed by the HMS
Management Division) under the Consolidated HMS FMP (NMFS, 2006). The
management of these sharks is divided into four species groups: large
coastal sharks (LCS), small coastal sharks (SCS), pelagic sharks, and
prohibited sharks. The LCS complex is further divided into sandbar
sharks, Aggregated LCS, and hammerhead sharks, with different
management measures for each group. The hammerhead shark management
group includes scalloped, smooth, and great hammerhead sharks.
In 2011, the HMS Management Division made an ``overfished'' and
``overfishing'' status determination of the scalloped hammerhead stock
(76 FR 23794; April 28, 2011) and was mandated to implement additional
conservation and management measures by 2013 to protect the scalloped
hammerhead shark stock from overexploitation. These measures, which
were finalized in July 2013 with publication of Amendment 5a to the
Consolidated HMS FMP (78 FR 40318; July 3, 2013), included separating
the commercial hammerhead shark quotas from the aggregated LCS
management group quotas, linking the Atlantic hammerhead shark quota to
the Atlantic aggregated LCS quotas, and linking 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 shark quota is
reached, then both the aggregated LCS and hammerhead shark 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 shark bycatch and additional mortality from
fishermen targeting other sharks within the LCS complex. The separation
of the hammerhead species for quota monitoring purposes from other
sharks within the LCS management unit will allow us to better manage
the specific utilization of the hammerhead shark complex, which
includes great hammerhead sharks.
One way that the HMS Management Division controls and monitors this
commercial harvest is by requiring U.S. commercial Atlantic HMS
fishermen who fish for or sell great hammerhead sharks to have a
Federal Atlantic Directed or Incidental shark limited access permit.
These permits are administered under a limited access program, and the
HMS Management Division is no longer issuing new shark permits.
Currently, 220 U.S. fishermen are permitted to target sharks managed by
the HMS Management Division in the Atlantic Ocean and Gulf of Mexico,
and an additional 265 fishermen are permitted to land sharks
incidentally. A directed shark permit allows fishermen to retain 36 LCS
sharks, which includes great hammerhead sharks, per vessel per trip. An
incidental permit allows fishermen to retain up to 3 LCS sharks, which
includes great hammerhead sharks, per vessel per trip. These limits
apply to all gear; however, starting in 2011, fishermen using pelagic
longline (PLL) gear and operating in the Atlantic Ocean, including the
Caribbean Sea, and dealers buying from vessels that have PLL gear
onboard, 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 S.
tiburo) (76 FR 53652; August 29, 2011). (This prohibition was
promulgated to carry out ICCAT Recommendation 10-08, which is discussed
in further detail below.) In addition to permitting and trip limit
requirements, logbook reporting or carrying an observer onboard may be
required for selected commercial fishermen. The head may be removed and
the shark may be gutted and bled, but the shark cannot be filleted or
cut into pieces while onboard the vessel and all fins, including the
tail, must remain naturally attached to the carcass through offloading.
Great hammerhead sharks may be retained by recreational Atlantic
HMS fishermen using either rod and reel or handline gear, as long as
tunas, swordfish, or billfish are also not retained (76 FR 53652;
August 29, 2011, promulgated to carry out ICCAT Recommendation 10-08).
Great hammerheads that are kept in the recreational fishery must have a
minimum size of 78 inches (1.98 m; 6.5 feet) fork length to ensure that
primarily mature individuals are retained, and only one shark, which
could be a great hammerhead, may be kept per vessel per trip. Since
2008, recreational
[[Page 33520]]
fishermen have been required to land all sharks with their head, fins,
and tail naturally attached.
Individual state fishery management agencies have authority for
managing fishing activity in state waters, which usually extends from
zero to three nautical miles (5.6 km) off the coast in most cases, and
zero to nine nautical miles (16.7 km) off Texas and the Gulf coast of
Florida. Federally permitted shark fishermen along the Atlantic coast
and in the Gulf of Mexico and Caribbean are required to follow Federal
regulations in all waters, including state waters. To aid in
enforcement and reduce confusion among fishermen, in 2010, the Atlantic
States Marine Fisheries Commission, which regulates fisheries in state
waters from Maine to Florida, implemented a Coastal Shark Fishery
Management Plan that mostly mirrors the Federal regulations for sharks,
including great hammerhead sharks. States in the Gulf of Mexico and
territories in the Caribbean Sea have also implemented regulations that
are mostly the same as the Federal regulations for sharks, including
great hammerhead sharks. However, the State of Florida, which has the
largest marine recreational fisheries in the United States and the
greatest number of HMS angling permits, recently went even further than
Federal regulations to protect the great hammerhead shark by
prohibiting the harvest, possession, landing, purchasing, selling, or
exchanging any or any part of a hammerhead shark (including scalloped,
smooth, and great hammerheads) caught in Florida's waters by Florida
fishermen (Florida Fish and Wildlife Conservation Commission, effective
January 1, 2012).
In addition, the HMS Management Division recently published an
amendment to the Consolidated HMS FMP that specifically addresses
Atlantic HMS fishery management measures in the U.S. Caribbean
territories (77 FR 59842; Oct. 1, 2012). Due to substantial differences
between some segments of the U.S. Caribbean HMS fisheries and the HMS
fisheries that occur off the mainland of the United States (including
permit possession, vessel size, availability of processing and cold
storage facilities, trip lengths, profit margins, and local consumption
of catches), the HMS Management Division implemented measures to better
manage the traditional small-scale commercial HMS fishing fleet in the
U.S. Caribbean Region. Among other things, this rule created an HMS
Commercial Caribbean Small Boat (CCSB) permit, which: allows fishing
for and sales of big-eye, albacore, yellowfin, and skipjack tunas,
Atlantic swordfish, and Atlantic sharks within local U.S. Caribbean
market; collects HMS landings data through existing territorial
government programs; authorizes specific gears; is restricted to
vessels less than or equal to 45 feet (13.7 m) length overall all; and
may not be held in combination with any other Atlantic HMS vessel
permits. However, at this time, fishermen who hold the CCSB permit are
prohibited from retaining Atlantic sharks, and are restricted to
fishing with only rod and reel, handline, and bandit gear under the
permit. Both the CCSB and Atlantic HMS regulations will help protect
great hammerhead sharks while in the northwest Atlantic Ocean, Gulf of
Mexico, and Caribbean Sea.
In other parts of the great hammerhead shark range, the ERA team
noted that regulations specific to great hammerhead sharks are lacking.
For example, in Central America and the Caribbean, management of shark
species remains largely disjointed, due in large part to the number of
sovereign states found in this region (Kyne et al., 2012). Some
countries are missing basic fisheries regulations whereas other
countries lack the capabilities to enforce what has already been
implemented. The Organization of the Fisheries and Aquaculture Section
of the Central American Isthmus (OSPECA) was formed to address this
situation by assisting with the development and coordination of fishery
management measures in Central America. OSPECA recently approved a
common regional finning regulation for eight member countries from the
Central American Integration System (SICA) (Belize, Costa Rica,
Dominican Republic, El Salvador, Guatemala, Honduras, Nicaragua, and
Panama). The regulation specifically requires sharks to be landed with
fins still attached for vessels fishing in SICA countries or in
international waters flying a SICA country flag. If fins are to be
traded in a SICA country, they must be accompanied by a document from
the country of origin certifying that they are not the product of
finning (Kyne et al., 2012). Other Central American and Caribbean
country-specific regulations include the banning or restriction of
longlines in certain fishing areas (Bahamas, Belize, Panama), seasonal
closures (Guatemala), shark fin bans (Colombia, Mexico, Venezuela) and
the prohibition of shark fishing (Bahamas and Honduras). Unfortunately,
enforcement of these regulations is weak, with many reports of illegal
and unregulated fishing activities (WildAid, 2003; Lack and Sant, 2008;
Agnew et al., 2009; Kyne et al., 2012; NMFS, 2013a).
In South America, Brazil has also banned finning and currently has
regulations limiting the extension of pelagic gillnets and prohibiting
trawls in waters less than 3 nautical miles (5.6 km) from the coast;
however, heavy industrial fishing off the coast of Brazil, with the use
of drift gillnets and longlines, remains largely unregulated, as does
the intensive artisanal fishery which accounts for about 50 percent of
the fishing sector.
In Europe, the European Parliament recently passed a regulation
prohibiting the removal of shark fins by all vessels in EU waters and
by all EU-registered vessels operating anywhere in the world. Many
individual European countries had previously implemented measures to
stop the practice of finning and conserve shark populations. For
example, England and Wales banned finning in 2009 and no longer issue
special permits for finning exceptions. France prohibits on-board
processing of sharks, and Spain recently published Royal Decree
N[deg]139/2011 in 2011, adding hammerhead sharks to their List of Wild
Species under Special Protection (Listado de Especies Silvestres en
R[eacute]gimen de Protecci[oacute]n Especial). This listing prohibits
the capture, injury, trade, import and export of hammerhead sharks,
including great hammerhead sharks, with a periodic evaluation of their
conservation status. Given that Spain is Europe's top shark fishing
nation, accounting for 7.3 percent of the global shark catch, and was
the world's largest exporter of shark fins to Hong Kong in 2008, this
new regulation should provide significant protection for great
hammerhead sharks from Spanish fishing vessels.
Although regulations in Europe appear to be moving towards the
sustainable use and conservation of shark species, these strict and
enforceable regulations do not extend farther south in the Eastern
Atlantic, where great hammerhead sharks are more frequently observed.
Some western African countries have attempted to impose restrictions on
shark fishing; however, these regulations either have exceptions,
loopholes, or poor enforcement. For example, Mauritania has created a
6,000 km \2\ coastal sanctuary for sharks and rays, prohibiting
targeted shark fishing in this region; however, sharks, such as the
great hammerhead shark, may be caught as bycatch in nets. Many other
countries, such as Namibia, Guinea, Cape-Verde, Sierra Leone, and
Gambia, have shark finning bans, but even with this regulation, great
hammerhead sharks may be caught with little to no restrictions on
harvest numbers. Many
[[Page 33521]]
of these state-level management measures also lack standardization at
the regional level (Diop and Dossa, 2011), which weakens some of their
effectiveness. For example, Sierra Leone and Guinea both require shark
fishing licenses; however, these licenses are much cheaper in Sierra
Leone, and as a result, fishermen from Guinea fish for sharks in Sierra
Leone (Diop and Dossa, 2011). Also, although many of these countries
have recently adopted FAO recommended National Plans of Action--Sharks,
their shark fishery management plans are still in the early
implementation phase, and with few resources for monitoring and
managing shark fisheries, the benefits to sharks from these regulatory
mechanisms (such as reducing overutilization) have yet to be realized
(Diop and Dossa, 2011).
In 2010, ICCAT adopted Recommendation 10-08 prohibiting the
retention of hammerheads caught in association with ICCAT-managed
fisheries. Each Contracting Party to ICCAT is responsible for
implementing this recommendation, and currently there are approximately
47 contracting parties (including the United States, the EU, Brazil,
Venezuela, Senegal, Mauritania, and many other Central American and
West African countries). ICCAT Recommendation 10-08 also includes a
special exception for developing coastal States, allowing them to
retain hammerhead sharks for local consumption provided that they
report their catch data to ICCAT, endeavor not to increase catches of
hammerhead sharks, and take the necessary measures to ensure that no
hammerhead parts enter international trade. As this exception allows
hammerhead sharks to be retained under certain circumstances, it may
provide a lesser degree of protection for hammerhead sharks when in the
Atlantic Ocean. However, based on the nominal catch data from ICCAT, it
does not appear that great hammerhead sharks have been or are currently
caught in large numbers by ICCAT vessels. Prior to Recommendation 10-
08, average reported great hammerhead catch was approximately 2 mt per
year (range: 0 to 19 mt; 1992--2010). In 2012, only fleets operating
under the Nigerian and St. Lucia flags reported catches of great
hammerhead sharks (total = 14 mt). These low numbers reported by ICCAT
vessels are likely a reflection of the low susceptibility of great
hammerhead sharks to ICCAT fisheries (see the Cortes et al. (2012)
Ecological Risk Assessment). Therefore, in addition to the overall low
vulnerability (susceptibility and productivity) of great hammerhead
sharks to ICCAT fisheries, further regulations prohibiting the
retention (and international trade as part of the exception) of
hammerhead sharks will greatly minimize the threat of overutilization
of this species within the Atlantic.
The RFMOs that cover the Indian and Pacific Oceans, including the
Indian Ocean Tuna Commission (IOTC), the Western and Central Pacific
Fisheries Commission (WCPFC), and the Inter-American Tropical Tuna
Commission (IATTC), require the full utilization of any retained
catches of sharks, with a regulation that onboard fins cannot weigh
more than 5 percent of the weight of the sharks. These regulations are
aimed at curbing the practice of shark finning, but do not prohibit the
fishing of sharks. In addition, these regulations may not be as
effective in stopping finning of sharks compared to those that require
fins to be naturally attached, as a recent study found many shark
species, including the great hammerhead shark, to have an average wet-
fin-to-round-mass ratio of less than 5 percent (Biery and Pauly, 2012).
In other words, fishing vessels operating in these RFMO convention
areas may be able to land more shark fins than bodies and still pass
inspection. However, these RFMOs do encourage the release of live
sharks, especially juveniles and pregnant females that are caught
incidentally and are not used for food and/or subsistence in fisheries,
and request the submission of data related to catches of sharks, down
to the species level where possible. Although there are no great
hammerhead-specific RFMO regulations in this part of its range, based
on observer data from these RFMOs, catches of great hammerhead sharks
are negligible (SPC 2010; H. Murua, personal communication).
Countries within the Indian Ocean that have specific measures to
prevent the waste of shark parts and discourage finning include Oman,
Seychelles, Australia, South Africa, and Taiwan. The Maldives have even
designated their waters as a shark sanctuary. In Australia, the states
and territories have implemented various shark regulations that are
likely to protect the species when inside Australia's EEZ. For example,
finning bans exist in all waters of Australia, although the strictness
of the ban (i.e., based on fin ratio or requirement to leave fins
attached) varies by state. In May 2012, the state of New South Wales
listed S. mokarran as a vulnerable species, making it illegal to catch
and keep, buy, sell, possess or harm the great hammerhead shark without
a specific permit, license or other appropriate approval. In
Australia's northern shark fisheries (JANSF and WANCSF), hammerhead
catches saw a significant decline from their peak in 2004/05 following
the implementation of stricter management regulations in 2005
(including area closures and longline and gillnet restrictions in
WANCSF). In 2008, the JANSF's export approval was revoked over concerns
about the ecological sustainability of the fishery. In 2009, the WANCSF
export approval expired. As such, no product from either fishery can
currently be legally exported. As the northern shark fisheries rely
upon shark fin exports for the majority of their income, these export
losses have effectively shut down the fisheries, and, consequently,
from 2009-2011 there was no reported activity in the northern shark
fisheries (McAuley and Rowland, 2012).
Other shark fishing countries in the Indian and Pacific Oceans
include Indonesia, India, Taiwan, and Costa Rica. Indonesia, which is
the top shark fishing nation in the world, currently has no
restrictions pertaining to shark fishing. In fact, Indonesian small-
scale fisheries, which account for around 90 percent of the total
fisheries production, are not required to have fishing permits (Varkey
et al., 2010), nor are their vessels likely to have insulated fish
holds or refrigeration units (Tull, 2009), increasing the incentive for
shark finning by this sector (Lack and Sant, 2012). Although Indonesia
adopted an FAO recommended shark conservation plan (National Plan of
Action--Sharks) in 2010, due to budget constraints, it can only focus
its implementation of key conservation actions in one area, East Lombok
(Satria et al., 2011). The current Indonesian regulations that pertain
to sharks are limited to those needed to conform to international
agreements (such as trade controls for certain species listed by the
Convention on International Trade in Endangered Species of Wild Fauna
and Flora (CITES) (e.g., whale shark) or prescribed by RFMOs) (Fischer
et al., 2012). However, with the new CITES listing of hammerhead sharks
on Appendix II (discussed below), Indonesia will need to implement
CITES trade rules for hammerhead sharks and ensure that international
trade in these species will not be detrimental to their survival.
A number of countries have also enacted complete shark fishing
bans, with the Bahamas, Marshall Islands, Honduras, Sabah (Malaysia),
and Tokelau (an island territory of New Zealand) adding to the list in
2011, and the Cook Islands in 2012. Shark sanctuaries can also be found
in the Eastern Tropical Pacific Seascape
[[Page 33522]]
(which encompasses around two million km \2\ of national waters,
coasts, and islands of Colombia, Costa Rica, Ecuador, and Panama,
including the Galapagos, Cocos, and Malpelo Islands), and in waters off
the Maldives, Mauritania, Palau, and French Polynesia.
In terms of legal international trade in the species, the ERA team
noted that in March 2013, at the CITES Conference of the Parties
meeting in Bangkok, member nations, referred to as ``Parties,'' voted
in support of listing three species of hammerhead sharks (scalloped,
smooth, and great hammerhead sharks) in CITES Appendix II--an action
that means increased protection, but still allows legal and sustainable
trade. CITES is an international agreement between governments that
regulates international trade in wild animals and plants. It encourages
a proactive approach and the species covered by CITES are listed in
appendices according to the degree of endangerment and the level of
protection provided. Appendix I includes species threatened with
extinction; trade in specimens of these species is permitted only in
exceptional circumstances. Appendix II includes species not necessarily
threatened with extinction, but for which trade must be controlled to
avoid exploitation rates incompatible with species survival. Appendix
III contains species that are protected in at least one country, which
has asked other CITES Parties for assistance in controlling the trade.
The CITES hammerhead shark listings will go into effect on
September 14, 2014. At that time, export of their fins, or any other
part of the animal, will require permits that ensure the products were
legally acquired and that the Scientific Authority of the State of
export has advised that such export will not be detrimental to the
survival of that species. Guyana and Yemen have entered reservations,
which means that they are not bound by CITES requirements when trading
in these species with countries not a party to CITES. Japan has also
taken a reservation but has stated that it will comply voluntarily with
the CITES requirements for export permits. Canada has also entered
reservations but this is temporary until they are able to implement
domestic regulations.
As a substantial lack of data, especially catch and trade data
specific to great hammerhead sharks, was noted as contributing to the
significant uncertainty in evaluating threats and the extinction risk
of the species, this CITES listing and subsequent management measures
to implement CITES trade regulations, should help decrease this
uncertainty, support sustainable trade in the species, and provide a
greater understanding of the extinction risk faced by the species.
The ERA team also expressed concerns regarding finning and illegal
harvest of great hammerhead sharks for the international shark fin
trade, but noted that the situation appears to be improving due to
current regulations and trends, and may not be as severe a threat to
great hammerhead sharks compared to other species. For example, unlike
the scalloped hammerhead shark, which schools and may be caught in
large numbers by vessels fishing illegally, the great hammerhead shark
is less susceptible to overutilization from illegal harvest due to its
solitary behavior and diffuse abundance. Although many of the reports
of illegal fishing in the status review document do not identify fins
down to species (see Miller et al., 2014 for details), the illegal
fishing occurred in known ``hot spots'' of scalloped hammerhead sharks.
These are areas where large numbers of scalloped hammerheads have been
known to aggregate and school, such as around the Galapagos, Malpelo,
Cocos and Revillagigedo Islands in the Eastern Tropical Pacific (Hearn
et al., 2010; Bessudo et al., 2011). Thus, it is likely that many of
the illegally obtained fins belonged to S. lewini. The status review
report also mentions a study that examined a small collection of
illegal fins confiscated from fishermen in northern Australian waters,
and found that the number of fins identified as scalloped hammerhead
sharks were almost double those that belonged to great hammerhead
sharks (Lack and Sant, 2008). In fact, the scalloped hammerhead shark
was the second highest source of illegal fins (behind the Whitecheek
shark--Carcharhinus dussumieri). In 2007, a sting operation that
confiscated 19,018 illegal fins at the border between Ecuador and Peru
also identified the fins down to species, and found that the fins
represented four species of sharks: bigeye thresher, pelagic thresher,
sandbar, and scalloped hammerhead sharks (O'Hearn-Gimenez, 2007). Based
on the location of many reported illegal fishing occurrences, and the
representation of S. lewini in identified fin hauls, it seems likely
that the vast majority of hammerhead sharks that are harvested by
illegal fishing vessels are the schooling scalloped hammerhead shark.
Also, as discussed above (with further details in Miller et al.,
2014), finning bans have been implemented by a number of countries, as
well as by nine RFMOs. These finning bans range from requiring fins
remain attached to the body to allowing fishermen to remove shark fins
provided that the weight of the fins does not exceed 5 percent of the
total weight of shark carcasses landed or found onboard. These
regulations are aimed at stopping the practice of killing and disposing
of shark carcasses at sea and only retaining the fins. Although they do
not prohibit shark fishing, they work to decrease the number of sharks
killed solely for the international shark fin trade, with some more
effective than others.
In addition to these finning bans, there has also been a recent
push to decrease the demand of shark fins, especially for shark fin
soup. Already, many hotels, restaurants, and supermarkets in Asia,
where shark fins are a top commodity for shark fin soup, have agreed to
stop serving shark fin products. For example, in Taiwan, the W Taipei,
the Westin Taipei, and the Silks Palace at National Palace Museum have
stopped serving shark fin dishes as part of their menus. In November of
2011, the Chinese restaurant chain South Beauty removed shark fin soup
from its menus, and in 2012, the luxury Shangri-La Hotel chain joined
this effort, banning shark fin from its 72 hotels, most of which are
found in Asia. Effective January 1, 2012, the Peninsula Hotel chain
(which covers Chinese restaurant and banqueting facilities in Hong
Kong, Shanghai, Beijing, Tokyo, Bangkok, and Chicago) stopped serving
shark fin and related products. Many supermarket chains in Asia also
vowed to halt the sale of shark fin products. In 2011, ColdStorage, a
chain with several outlets in Singapore, banned the sale of shark fin
from its stores, and in 2012, the Singapore supermarket chains
FairPrice and Carrefour stated they would also stop selling shark fin
in outlets in the city-state. Most recently, China, a large consumer of
shark fins, prohibited shark fins at all official reception dinners
(Ng, 2013). Clarke et al. (2007) documented that shark fin traders cite
hammerheads as the sources of the best quality fin needles for
consumption at banquets, so these prohibitions could work to decrease
the global demand for hammerhead fins. In the United States, for
example, exports of dried Atlantic shark fins significantly dropped
after the passage of the Shark Finning Prohibition Act (which was
enacted in December of 2000 and implemented by final rule on February
11, 2002; 67 FR 6194), and again in 2011 (decreased by 58 percent),
with the passage of the 2010 Shark Conservation Act and the ban on
possession and trade of shark fins passed in several U.S. states (NMFS,
2012; NMFS, 2013b).
[[Page 33523]]
Also in 2011, the price per kg of shark fin reached its highest (~$100/
kg) and, as such, one would expect an increase in exports (due to the
increase in product price); however, as mentioned above, the opposite
was true, suggesting that these types of finning bans and fin trade
regulations are likely effective at discouraging U.S. fishermen from
fishing for sharks solely for the purpose of the international fin
trade. In 2012, the value of fins decreased indicating that perhaps the
worldwide demand for fins is also on a decline (NMFS, 2012; NMFS
2013b).
Thus, although great hammerhead fins are one of the most prized in
the international shark fin trade (Abercrombie et al., 2005), the
extent of legal and illegal harvest on great hammerhead sharks for this
trade was not viewed as significant enough to decrease the species'
abundance to the point where it may be at risk of extinction due to
environmental variation, anthropogenic perturbations, or depensatory
processes. Additionally, as the demand for shark fins continues to
decline (as demonstrated by the increase in finning bans, decrease in
shark fin food products, and decrease in shark fin price), so should
the threat of finning and illegal harvest.
Based on the above review of regulatory measures (in addition to
the regulations described in Miller et al., 2014) the ERA team
concluded that these existing regulations have a small to moderate
effect on the species' extinction risk. The team noted that some areas
of the species' range do have adequate measures in place to prevent
overutilization, such as in the Northwest Atlantic where U.S. fishery
management measures to rebuild the scalloped hammerhead populations are
helping to monitor the catch of great hammerheads, preventing any
further population declines. These U.S. conservation and management
measures (as previously summarized with additional details in Amendment
5a to the Consolidated HMS FMP (78 FR 40318; July 3, 2013)) are viewed
as adequate in decreasing the extinction risk to the great hammerhead
shark by minimizing demographic risks (preventing further abundance
declines) and the threat of overutilization (strictly managing and
monitoring sustainable catch rates) currently and in the foreseeable
future. Although regulations specific to great hammerhead sharks are
lacking in other parts of its range, fishery interactions are rare and
thus the effects of the current regulatory measures do not appear to be
significantly increasing the species' risk of extinction. This species
is not observed or caught in large numbers by global fisheries and it
is uncertain whether overutilization of the species is a significant
threat (see Overutilization for Commercial, Recreational, Scientific or
Educational Purpose section discussed earlier in this notice).
Therefore, based on the best available information, we find that the
threat of inadequate current regulatory mechanisms is likely having a
small effect on the species' risk of extinction; however, improvements
are needed in the monitoring and reporting of fishery interactions.
Other Natural or Man-Made Factors Affecting Its Continued Existence
The ERA team identified biological vulnerability in the form of
high at-vessel fishing mortality as a potential factor that may
increase the species' risk of extinction. Great hammerhead sharks are
obligate ram ventilators and suffer very high at-vessel fishing
mortality in bottom longline fisheries (Morgan and Burgess, 2007;
Morgan et al., 2009). From 1994-2005, NMFS observers calculated that
out of 178 great hammerheads caught on commercial bottom longline
vessels in the northwest Atlantic and Gulf of Mexico, 93.8 percent were
dead when brought aboard. Size did not seem to be a factor influencing
susceptibility, whereas soak time of the longline had a positive effect
on the likelihood of death, and bottom water temperature had a negative
effect (Morgan and Burgess, 2007). Morgan et al. (2009) also documented
over 90 percent at-vessel mortality rates for great hammerhead sharks
for soak times ranging anywhere from < 4 hours to over 24 hours.
In a study that examined the physiological stress responses to
being caught in fishing gear and post-release survival, great
hammerhead sharks were once again found to be extremely vulnerable to
capture stress and mortality (Gallagher et al., in press). The study
specifically compared five shark species (blacktip, bull, lemon, great
hammerhead, and tiger) and their responses to being caught on drum
lines. Fight times on the hooks were recorded, blood samples taken,
reflexes tested, and satellite tags were deployed on a select number of
sharks. Results from the study showed that blood lactate levels (which
were positively correlated with fight time) were significantly higher
in great hammerhead sharks compared to the other species (Gallagher et
al., in press). Previous studies have demonstrated a positive
relationship between blood lactate levels and likelihood of post-
release mortality, with lactate values of around 16-20 mmol/l
associated with moribund sharks (Gallagher et al., in press). In great
hammerhead sharks, the blood lactate values averaged 17.00 mmol/l
(2.78) after fight times of 17-131 minutes (Gallagher et
al., in press). One tagged great hammerhead, which had a 24-minute
fight time and lactate value of 19 mmol/l, was released alive but died
after less than 10 minutes. Compared to the other shark species, the
great hammerhead also had the lowest tag reporting rate, which the
authors suggest could be an indication of low post-release survival
(Gallagher et al., in press).
After an evaluation of the above information, the ERA team noted
that the extent of this vulnerability on the species' extinction risk
is unknown and hard to quantify. Fisheries information is lacking and
it is likely that most of the fishing mortality on this species is
through capture in gillnets, where its biological vulnerability would
not present an issue as the species would not likely be released after
capture. However, given the uncertainties, the ERA team placed 53
percent of their likelihood votes in the ``Unknown'' threat effect
level. The effect level that received the second highest number of
votes was the ``Small effect'' category as the team acknowledged that
there may be some concern that its biological vulnerability could
exacerbate extinction risk when coupled with other threats or
demographic risks.
Significant Portion of Its Range
The definitions of both ``threatened'' and ``endangered'' under the
ESA contain the term ``significant portion of its range'' (SPOIR) as an
area smaller than the entire range of the species which must be
considered when evaluating a species risk of extinction. The phrase has
never been formally interpreted by NMFS. With regard to SPOIR, the
Services have proposed a ``Draft Policy on Interpretation of the Phrase
`Significant Portion of Its Range' in the Endangered Species Act's
Definitions of `Endangered Species' and `Threatened Species' '' (76 FR
76987; December 9, 2011), which is consistent with our past practice as
well as our understanding of the statutory framework and language.
While the Draft Policy remains in draft form, the Services are to
consider the interpretations and principles contained in the Draft
Policy as non-binding guidance in making individual listing
determinations, while taking into account the unique circumstances of
the species under consideration.
The Draft Policy provides that: (1) If a species is found to be
endangered or
[[Page 33524]]
threatened in only a significant portion of its range, the entire
species is listed as endangered or threatened, respectively, and the
Act's protections apply across the species' entire range; (2) a portion
of the range of a species is ``significant'' if its contribution to the
viability of the species is so important that, without that portion,
the species would be in danger of extinction; (3) the 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; and (4) if the species is not endangered or
threatened throughout all of its range, but it is endangered or
threatened within a significant portion of its range, and the
population in that significant portion is a valid DPS, we will list the
DPS rather than the entire taxonomic species or subspecies.
After a review of the best available information, the ERA team
concluded, and we agree, that the data do not indicate any portion of
the great hammerhead shark's range as being more significant than
another. Great hammerhead sharks are highly mobile, with a global
distribution and very few restrictions governing their movements.
Although there was preliminary evidence of possible genetic
partitioning between ocean basins, this was based on an abstract with
no accompanying data or information that we could evaluate, and a study
with a limited sample size (see Distinct Population Segment Analysis
section above for more information). Based on these deficiencies, we
did not find that the best available information supported a conclusion
that the loss of genetic diversity from one portion (such as loss of an
ocean basin population) would result in the remaining population
lacking enough genetic diversity to allow for adaptations to changing
environmental conditions. Similarly, we did not find that loss of any
portion would severely fragment and isolate the great hammerhead
population to the point where individuals would be precluded from
moving to suitable habitats or have an increased vulnerability to
threats. As previously mentioned, the great hammerhead shark is highly
mobile, with diffuse abundance, and no known barriers to migration.
Loss of any portion of its range would not likely isolate the species
to the point where the remaining populations would be at risk of
extinction from demographic processes. In fact, we found no information
that would suggest that the remaining populations could not repopulate
the lost portion. Areas exhibiting source-sink dynamics, which could
affect the survival of the species, were not evident in any part of the
great hammerhead shark 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. There is little to no information regarding nursery
grounds or other important habitats utilized by the great hammerhead
sharks that could be considered limiting factors for the species'
survival. 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. Overall, we did not find any
evidence to suggest that any specific portion of its range had
increased importance over another with respect to the species'
survival. As such, when we considered the overall extinction risk of
the species, we considered it throughout the species' entire range.
Overall Risk Summary
Guided by the results from the demographic risk analysis and
threats assessment, the ERA team members used their informed
professional judgment to make an overall extinction risk determination
for the great hammerhead shark now and in the foreseeable future. The
ERA team concluded that the great hammerhead shark is currently at a
low risk of extinction; however, they expressed significant
uncertainty, due to data limitations from the best available
information, by almost equally distributing likelihood points in two
other risk categories. Likelihood points attributed to the current
level of extinction risk categories were as follows: No or Very Low
Risk (13/40), Low Risk (15/40), Moderate Risk (11/40), High Risk (1/
40). None of the team members placed a likelihood point in the ``Very
high risk'' category, indicating their strong certainty that the
species is not currently at a very high risk of extinction. The ERA
team reiterated that the great hammerhead shark is likely naturally low
in abundance and there is no evidence to suggest depensatory processes
are currently at work. The species is found globally, throughout its
historical range, appears to be well-adapted and opportunistic, and is
not limited by habitat. The team noted that only one scientifically-
robust study has shown large declines in the population using
fisheries-independent data; however, this study was conducted in a
small, localized area (off a beach in South Africa--Dudley and
Simpfendorfer, 2006) and does not represent the global population
status. As discussed previously, there were flaws in the other studies
cited within the status review report, including questionable species
discrimination within the datasets (as only recently has more attention
been paid to accurately identifying hammerhead sharks down to species),
models that are highly sensitive to data series, differences in the
complexity of models, large error bars in results data, short time
series or small number of observations used in the studies. Even after
taking into consideration the flaws within the datasets, the ERA team
found the results do not demonstrate that the great hammerhead shark is
at risk of extinction due to its current abundance. Throughout the
species' range, observations of its abundance are variable, with
reports of increasing, decreasing, and stable or no trends. The species
is also rare in fisheries data, either due to lack of reporting or
simply not present in common fishing grounds (or susceptible to fishing
gear, see Ecological Risk Assessment results). As the main threat that
the ERA team identified was overutilization due to fisheries (with
references to historical overutilization), the absence of the species
in fisheries data suggests that this threat is either being minimized
by existing regulations or is not significantly contributing to the
extinction risk of the species at this time (as the abundance data do
not indicate that the species has been fished to near extinction).
In evaluating the extinction risk through the foreseeable future,
the ERA team had increased confidence that the risk of extinction would
remain low, or further decrease, placing 85 percent of their likelihood
points in the ``No or Very Low Risk'' and ``Low Risk'' categories.
Likelihood points attributed to each risk category in the foreseeable
future are as follows: No or Very Low Risk (16/40), Low Risk (18/40),
Moderate Risk (6/40). None of the team members placed a likelihood
point in the ``High risk'' or ``Very High Risk'' categories for the
overall level of extinction risk in the foreseeable future, indicating
their strong certainty that the species will not be strongly influenced
by stochastic or depensatory processes that place its future survival
into question. The available information indicates that most of the
observed declines occurred in the 1980s, before any significant
management regulations.
[[Page 33525]]
Since then, current regulatory measures in many parts of the great
hammerhead shark's range are minimizing the threat of overutilization.
For example, the comprehensive science-based management and enforceable
and effective regulatory structure within the U.S. Northwest Atlantic
will help monitor and prevent further declines of great hammerhead
sharks while in these waters, and the implementation of ICCAT
Recommendation 10-08 will provide increased protection for great
hammerhead sharks throughout the entire Atlantic Ocean into the
foreseeable future. In the rest of the species' range, rare fisheries
interactions seem to imply that existing management measures (such as
RFMO recommendations, national shark fishing measures, and shark fin
bans) may be effective at minimizing overutilization of the species,
with trends that are moving toward more restrictive trade and decreased
demand in shark fin products, which indicate a decreased likelihood of
extinction of the global population in the foreseeable future. Thus,
the ERA team predicted that in the foreseeable future, the species will
unlikely be at risk of extinction due to trends in its abundance,
productivity, spatial structure, or diversity or influenced by
stochastic or depensatory processes.
Similarity of Appearance Listing
Section 4 of the ESA (16 U.S.C. 1533(e)) additionally 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)).
The WEG petition requested that we also consider listing the great
hammerhead shark as threatened or endangered based on its similarity of
appearance to the scalloped hammerhead shark. Four DPSs of scalloped
hammerhead shark have been proposed for listing under the ESA (78 FR
20717; April 5, 2013). Although the great hammerhead shark and
scalloped hammerhead shark share similar features (such as the unique
head shape), we have not found evidence that enforcement personnel
would have substantial difficulty in differentiating the two species.
The great hammerhead shark is the largest of the hammerhead shark
species, reaching lengths of up to 610 cm TL (Compagno, 1984) but more
commonly observed as > 400 cm TL (Miller et al., 2014) and averaging
over 500 pounds (230 kg) (Bester, n.d.). On the other hand, observed
maximum sizes of scalloped hammerhead sharks range from 331-346 cm TL
(Stevens and Lyle, 1989; Chen et al., 1990) with a maximum recorded
weight of 336 pounds (152.4 kg) (Bester, n.d.). In addition to their
sizes, the shapes of their head are also distinctive and aid in the
differentiation of the two species. In the great hammerhead shark, the
front margin of the head is nearly straight, forming a ``T-shape,''
with a shallow notch in the middle, whereas the scalloped hammerhead
shark has a broadly arched head, with distinct indentations in the
center as well as on either side of the middle notch (Bester, n.d.).
The fins of these two species can also be distinguished without
difficulty. The great hammerhead shark has a very tall, distinctive,
crescent-shaped first dorsal fin whereas the first dorsal fin of a
scalloped hammerhead shark is shorter and has a rounded apex
(Abercrombie et al., 2013). According to a genetic study that examined
the concordance between assigned Hong Kong market categories and the
corresponding fins, the great hammerhead market category ``Gu pian''
had an 88 percent concordance rate, indicating that traders are able to
accurately identify and separate great hammerhead shark fins from the
other hammerhead species (Abercrombie et al., 2005; Clarke et al.,
2006a). In addition, many RFMOs and national and international fishery
managers have started distributing shark and fin guides for fishermen
in order to help with increased accuracy in reporting shark catches
down to the species level.
Given the distinctive head and body characteristics of the great
hammerhead shark and the scalloped hammerhead shark, and evidence that
fins of the species can also be accurately identified and separated, we
conclude that enforcement personnel would not have substantial
difficulties in attempting to differentiate between the great
hammerhead shark and the scalloped hammerhead shark. Therefore, we are
not considering a similarity of appearance listing at this time.
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 (78 FR 24701; April 26, 2013),
the status review report (Miller et al., 2014), and other published and
unpublished information, and have consulted with species experts and
individuals familiar with great hammerhead sharks. We considered each
of the statutory factors to determine whether it presented an
extinction risk to the species on its own. We also considered the
combination of those factors to determine whether they collectively
contributed to the extinction of the species. As required by the ESA,
Section 4(b)(1)(a), we also took into account efforts to protect great
hammerhead sharks by states, foreign nations and others and evaluated
whether those efforts provide a conservation benefit to the species. As
previously explained, no portion of the species' range is considered
significant and we did not find biological evidence that would indicate
that any population segment of the great hammerhead shark would qualify
as a DPS 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.
We conclude that the great hammerhead shark is not presently in
danger of extinction, nor is it likely to become so in the foreseeable
future throughout all of its range. We summarize the factors supporting
this conclusion as follows: (1) The species is made up of a single
population over a broad geographic range, with no barrier to dispersal;
(2) its current range is indistinguishable from its historical range
and there is no evidence of habitat loss or destruction; (3) while the
species possesses life history characteristics that increase its
vulnerability to harvest, it has been found to be less susceptible to
pelagic longline fisheries compared to other shark species (based on
results from Ecological Risk Assessments), decreasing the chance of
substantial fishing mortality from this common
[[Page 33526]]
fishery that operates throughout its range; (4) the best available
information indicates that abundance is naturally low and variable
across the species' range, with reports of localized population
declines but also evidence of stable and/or increasing abundance
estimates; (5) based on the ERA's assessment, the current population
size, while it has likely declined from historical numbers, is
sufficient to maintain population viability into the foreseeable
future; (6) the main threat to the species is fishery-related mortality
from global fisheries; however, information on harvest rates is
inconclusive due to poor species discrimination and significant
uncertainties in the data, with the best available information
indicating low utilization of the species (rare in fisheries records
and minor component of illegal fin hauls); (7) there is no evidence
that disease or predation is contributing to increasing the risk of
extinction of the species; (8) existing regulatory mechanisms
throughout the species' range appear effective in addressing the most
important threats to the species (harvest), but it is unknown if they
will remain so if harvest increases because many of the regulations are
not specific to hammerhead shark utilization; and, (9) while the global
population has likely declined from historical numbers, there is no
evidence that the species is currently suffering from depensatory
processes (such as reduced likelihood of finding a mate or mate choice
or diminished fertilization and recruitment success) or is at risk of
extinction due to environmental variation or anthropogenic
perturbations.
Based on these findings, we conclude that the great hammerhead
shark is not currently in danger of extinction throughout all or a
significant portion of its range nor is it likely to become so within
the foreseeable future. Accordingly, the great hammerhead shark does
not meet the definition of a threatened or endangered species and our
listing determination is that the great hammerhead shark does not
warrant listing as threatened or endangered at this time.
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 5, 2014.
Samuel D. Rauch III,
Deputy Assistant Administrator for Regulatory Programs, National Marine
Fisheries Service.
[FR Doc. 2014-13621 Filed 6-10-14; 8:45 am]
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