[Federal Register Volume 73, Number 3 (Friday, January 4, 2008)]
[Pages 843-847]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E7-25643]



National Oceanic and Atmospheric Administration

[Docket No. 071221887-7889-01]
RIN 0648-XE55

Endangered and Threatened Species; ``Not Warranted'' Endangered 
Species Act Listing Determination for the Atlantic White Marlin

AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and 
Atmospheric Administration (NOAA), Commerce.

ACTION: Notice of finding under the Endangered Species Act and 
availability of status review document.


SUMMARY: We, NMFS, announce our finding that listing the Atlantic white 
marlin (Tetrapturus albidus) as an endangered or threatened species 
under the Endangered Species Act (ESA) is not warranted, and we 
announce the availability of the status review document.

DATES: The finding announced in this notice was made on December 26, 

ADDRESSES: A copy of the status review document may be downloaded from 
the following web address: http://sero.nmfs.noaa.gov. Requests for a 
hard copy of the status review document should be addressed to Dr. 
Stephania Bolden, NMFS Southeast Regional Office, 263 13\th\ Avenue 
South, St. Petersburg, FL 33701.

Regional Office (727) 824-5312, or Marta Nammack, NMFS, Office of 
Protected Resources (301) 713-1401.



    In August 2001, we received a petition from the Biodiversity Legal 
Foundation (subsequently renamed the Center for Biological Diversity, 
or CBD) and James R. Chambers requesting us to list the Atlantic white 
marlin (Tetrapturus albidus) as a threatened or endangered species 
under the ESA. We convened a status review team (SRT) to assess the 
species' status and the degree of threat to the species with regard to 
section 4(a)(1) factors in the ESA. The 2002 SRT determined that two of 
these section 4(a)(1) factors were of concern for white marlin: 
overutilization and the inadequacy of existing regulatory mechanisms. 
While the 2002 SRT concluded that the white marlin stock had not 
declined to levels at which it was then in danger of extinction, it 
noted that the stock could decline to a level that would warrant ESA 
protection if fishing mortality was not reduced significantly and 
relatively quickly. After considering the conclusions of the 2002 SRT, 
we determined that listing white marlin was not warranted (67 FR 57204; 
September 9, 2002). Subsequently, CBD and the Turtle Island Restoration 
Network (TIRN) filed a complaint in the district court for the District 
of Columbia challenging our listing decision. A settlement agreement 
was reached wherein it was agreed that we would revisit the status of 
the white marlin following the 2006 stock assessment by the 
International Commission for the Conservation of Atlantic Tunas 
    Following ICCAT's completion of its 2006 white marlin stock 
assessment, we announced that a status review of the Atlantic white 
marlin was initiated and

[[Page 844]]

solicited information regarding the status of and threats to the 
species (71 FR 76639; December 21, 2006). NMFS' Southest Regional 
Office (SERO) convened a new biological review team (BRT) to commence a 
new comprehensive status review. This BRT incorporated results from 
both the 2002 and 2006 ICCAT stock assessments, and reviewed the 2002 
status review document, papers prepared at workshops and symposia to 
assist in the new stock assessment, current journal articles, reports 
from the 2004 billfish grant program, information submitted in response 
to our request for additional information, presentations by invited 
experts, and existing management of the fisheries in order to determine 
the status of and threats to the white marlin.
    The BRT prepared a status review document that represents their 
efforts to compile and evaluate the best scientific and commercial data 
available on white marlin to date. The BRT sought and incorporated peer 
review comments on the status review document. The BRT submitted their 
final status review document to SERO on December 10, 2007. Copies of 
the status review document are available upon request (see ADDRESSES).

Life History

    White marlin are billfish (Family Istiophoridae) that inhabit the 
tropical and temperate waters of the Atlantic Ocean and adjacent seas. 
Distribution of white marlin differs from the blue marlin (Makaira 
nigricans) and sailfish (Istiophorus platypterus) that range throughout 
both the Atlantic and Indo-Pacific regions. White marlin exhibit 
sexually dimorphic growth patterns, with females growing larger than 
males. White marlin are primarily general piscivores, but also feed on 
squid and other prey items. Spawning activity occurs during the spring 
(March through June) in northwestern Atlantic tropical and sub-tropical 
waters marked by relatively high surface temperatures (20[deg]-
29[deg]C) and salinities (> 35 ppt). It is believed there are at least 
five spawning areas in the western north Atlantic: northeast of Little 
Bahama Bank off the Abaco Islands; northwest of Grand Bahama Island; 
southwest of Bermuda; the Mona Passage, east of the Dominican Republic; 
and the Gulf of Mexico. There is a paucity of information regarding the 
age and growth of white marlin.
    Recently both morphometric and genetic information has provided 
evidence that there is a fifth species of Istiophoridae in the western 
North Atlantic - the roundscale spearfish (T. georgii). The roundscale 
spearfish closely resembles the white marlin, and the two may often be 
confused. Roundscale spearfish are not hybrids; they have a clearly 
different genetic lineage to sympatric billfish species. Limited data 
indicate that the roundscale spearfish is distributed widely in the 
western North Atlantic and is particularly abundant in the Sargasso 
Sea. Little is known about the life history of the roundscale 
spearfish. Further, the so-called ``hatchet marlin'' (Tetrapturus sp.), 
another putative congener that exhibits truncated dorsal and anal fins, 
is likely a phenotypic expression exhibited in both roundscale 
spearfish and white marlin and not a separate species.
    We determined that the Atlantic white marlin constitutes a single 
species throughout the Atlantic Ocean, there are no populations that 
warrant consideration of listing in a significant portion of the 
species' range, and there are no populations of the species that meet 
the discrete and significant standards set forth in our policy 
regarding recognition of distinct vertebrate population segments (61 FR 
4722; February 7, 1996). There is no information that indicates that 
any segment of the white marlin population is discrete or distinct, or 
that there is any specific geographic area within the Atlantic Ocean 
that should be considered more or less significant than another. White 
marlin are considered to be a panmictic species: individuals move about 
freely within the Atlantic Ocean, over thousands of miles, and breed 
freely with other members of the population. Presence of larvae 
suggests there are at least five spawning areas in the western north 
Atlantic Ocean, and there is no evidence to suggest special nursery 
areas. No population of white marlin is markedly separated from other 
populations of the same taxon, nor is there biological, ecological, or 
genetic evidence to suggest unusual or unique populations, or 
populations that are more at risk than others.

Fishery Landings and Management

    Atlantic billfish, including white marlin, have historically been 
landed as incidental catch of foreign and domestic commercial pelagic 
longline fisheries, or in directed recreational and artisanal 
fisheries. The majority of billfish fishing mortality in the Atlantic 
Ocean results from pelagic longline fisheries: total Atlantic-wide 
longline landings of white marlin mostly range between 1,000 to 2,000 
metric tons (mt) annually, of which the United States accounts for 
about 5 percent. While the directed commercial effort is principally 
targeted toward tuna species and swordfish, billfish occur in the same 
area as these other pelagic species, making them susceptible to the 
gear. Although total Atlantic-wide white marlin landings from longline 
fisheries have fluctuated between 610 and 1,966 mt over the past 25 
years, total landings have declined annually from 1,242 mt to 610 mt 
between 2000 and 2004 (the last year for which landings data are 
available). The U.S. proportion of total Atlantic-wide white marlin 
landings has been reduced from a 25-year average of 5 percent to 3 
percent of the 2000-2004 mean reported total (29 mt of 861 mt total).
    White marlin, along with other billfish and tunas, are managed 
internationally by the member nations of theICCAT). ICCAT, through the 
Standing Committee for Research and Statistics, conducts regular stock 
assessments for species under its purview: white marlin stock 
assessments were conducted in 2002 and 2006, and a 2010 assessment is 
scheduled. By consensus ICCAT adopts binding resolutions and makes 
recommendations to manage for maximum catch of species under its 
purview. ICCAT's Compliance Committee tracks landings and makes 
official determinations of non-compliance.
    Recreational fishers seek Atlantic blue marlin, white marlin, and 
sailfish as highly-prized species in the United States, Venezuela, 
Bahamas, Brazil, and many countries in the Caribbean Sea and west coast 
of Africa. White marlin are managed in the United States under the 
Consolidated Atlantic Highly Migratory Species Fishery Management Plan 
(FMP) and previously under the Billfish FMP. The FMP prohibits 
retention, landing, or sale of billfish (including white marlin) caught 
by commercial fishing vessels in U.S. waters, reserving those species 
for recreational anglers. The objective of the FMP is to end 
overfishing and rebuild stocks. In addition, the FMP seeks to 
coordinate domestic regulations with international management measures 
to control Atlantic-wide fishing mortality. In the United States, 
Atlantic blue marlin, white marlin, and Atlantic sailfish can be landed 
only by recreational fishermen fishing from either private vessels or 

Status of the Species

    Population estimates available for the 2007 status review indicate 
that the number of white marlin in the size range vulnerable to the 
commercial longline fishery is between 100,000 and 2,000,000, likely 
around 200,000, and that the current stock of white marlin is on the 
order of 20 percent carrying capacity (i.e., K) or greater. Population

[[Page 845]]

abundance trajectories in the 2006 ICCAT stock assessment no longer 
exhibit the long-term downward trend in population abundance seen in 
the 2002 ICCAT stock assessment; population estimates indicate both an 
increase in number and in the ratio of current biomass to unfished 
biomass (i.e., B/K). Atlantic-wide white marlin landings, as reported 
by ICCAT, have been continually reduced since 1996, and have been less 
than 1,000 mt for the last 4 years. The calculated probabilities of 
white marlin biomass under five fishing mortality projections 
considered (from 0.16 - 0.32) were more optimistic in 2007 relative to 
2002. Estimates of fishing mortality (i.e., F) decreased annually from 
17 percent in 2002 to 9 percent in 2006.
    We agree with the BRT that white marlin population models likely 
include a composite of data for white marlin and roundscale spearfish 
combined, as roundscale spearfish have been recorded as white marlin, 
and hence, all stock assessment parameters (including abundance, 
landings, fishing mortality) reflect the status of the two species 
combined. No information is available describing interspecific 
competition, or potential geographic overlap/separation, between the 
roundscale spearfish and white marlin. Limited data suggest the 
roundscale spearfish is widely distributed in the western North 
Atlantic, and abundant in the Sargasso Sea area during the winter 
period. It is unknown whether the proportion of either species has 
changed over time, and it is not possible to separate the two species 
in the historical catch records.
    It is pragmatic to conclude that the data used in the ICCAT white 
marlin stock assessments is overwhelmingly dominated by white marlin 
(T. albidus) relative to roundscale spearfish (T. georgii). Roundscale 
spearfish have been intermittently referenced in the scientific 
literature since 1840. Since then, it has taken more than 150 years to 
observe a sufficient number of specimens to clearly identify the 
species via genetic tissues and morphometrics. There is no information 
available suggesting differences between the species that would 
indicate that either species has a greater or less susceptibility to be 
caught in the fishery, nor information regarding likelihood of 
catchability differences between species by gear type, baits, season, 
or geographic area. Given the difficulty in visually differentiating 
the roundscale spearfish from the white marlin (scale morphology and 
relationship between length of anal fin relative to distance between 
anus and leading edge of anal fin), it is easy to understand why 
confusion between the species has occurred. Meanwhile, journal articles 
noting the roundscale spearfish have been infrequent, indicating rarity 
of species; a greater number of specimens would have led to an earlier 
clarification between the two species. The only data available 
regarding proportion of white marlin to roundscale spearfish are 
extremely limited in time and space; a genetic re-analysis of specimens 
identified at the dock as white marlin over the last few years during a 
single tournament confirmed that 17.5 percent were actually roundscale 
spearfish. Therefore, we conclude that while based on a composite of 
the two species, the ICCAT stock assessment indicators (e.g., K) for 
white marlin overwhelmingly reflect the status of the white marlin.
    We concur with the BRT's finding that there is no indication 
depensation is occurring. There is no evidence that any white marlin 
size class has been lost, nor any reason to expect one to be lost. 
Based on catch distributions from 1950 through 2004, there is no 
evidence of range constriction for white marlin. Both the BRT and NMFS 
find that compliance with ICCAT requirements by member nations and 
white marlin population trends improved between 2002 and 2006 as 
exhibited through real catch reductions and stable/increasing catch per 
unit effort (CPUE); this is an expected response to reduced fishing 
mortality. Notably, CPUE would also respond similarly to a large number 
of year classes in the population and/or surprisingly stable 
recruitment from year to year. While the extent of compliance with 
ICCAT recommendations and illegal, unreported, and unregulated (IUU) 
fishing are not completely understood, the best available information 
indicates that the current regulatory mechanisms have been sufficient 
to prevent continued stock decline of white marlin. We conclude that it 
is likely that, under current management regimes, the white marlin 
stock will remain stable or continue to increase. It appears that both 
decreasing population size and biomass, and sustained increase in 
fishing mortality (i.e., F), have been abated by management efforts.

Factors Affecting Atlantic White Marlin

    The 2007 BRT examined the ESA section 4(a)(1) factors as they apply 
to white marlin: 1) the present or threatened destruction, 
modification, or curtailment of its habitat or range; 2) 
overutilization for commercial, recreational, scientific, or 
educational purposes; 3) disease or predation; 4) the inadequacy of 
existing regulatory mechanisms; and 5) other natural or manmade factors 
affecting its continued existence. The two criteria the BRT was most 
concerned about for white marlin were overutilization and the adequacy 
of existing regulatory mechanisms. The BRT equated overfishing with 
overutilization and determined that the white marlin are not being 
overutilized, as population abundances no longer exhibit the 2002 
downward trend, and population estimates indicate both an increase in 
number and the ratio of current biomass to unfished biomass; we agree 
that both terms refer to overexploitation to a point of diminishing 
    We examined the ESA section 4(a)(1) factors relative to white 
marlin based on the status review document, and our conclusions for 
each follow: 1) There is no evidence of present or threatened 
destruction, modification, or curtailment of its range or habitat; 2) 
overutilization has previously occurred, but is not currently 
occurring; 3) there is no evidence that predation or disease is 
affecting the white marlin; 4) current regulatory mechanisms are 
adequate to prevent continued stock decline of white marlin; and 5) no 
natural or manmade factors were identified that were affecting the 
continued existence of the white marlin. While white marlin are almost 
certainly overfished as evidenced by a long history of exploitation 
that has probably depleted the population below the management target, 
overfishing, and thus overutilization, does not appear to be occurring 
today as current ratios of fishing mortality relative to the largest 
sustainable catch (i.e., F/Fmsy) estimates are reported as both greater 
and less than one depending on the index. Once overfishing for a 
species has ended, it may take several years before the stock will no 
longer be considered overfished. A population can be considered to be 
overfished without undergoing overfishing (i.e., there is a lag effect 
as the population recovers from overfishing).
    We concur with the BRT that domestic measures by the United States 
alone will have a negligible impact on the stock status of white 
marlin. Mandatory measures implemented by ICCAT for all member 
countries appear to be having some success, as the most recent stock 
assessment indicates that a slight increase was observed in the 2001-
2004 white marlin abundance estimates. It is noteworthy that this 
increasing trend was observed even though the 67 percent reduction in 
white marlin landings mandated by ICCAT in 2000 has not yet been 
achieved (average catch from 2000 -

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2004 was 36 percent of the maximum catch in 1996 or 1999). There is 
most likely not full compliance by all parties with all management 
measures, and there may be an unknown impact from IUU fishing. 
Regardless, real catch reductions are apparent in the data, and, under 
current management regimes, it is likely the white marlin stock will 
remain stable or continue to increase.

Population Modeling and Endangerment Assessment

    We believe that the metrics developed by the BRT to determine 
endangered or threatened status of the white marlin after a review of 
the quantitative and qualitative guidelines used by other conservation 
organizations (American Fisheries Society (AFS), World Conservation 
Union (IUCN), and Convention for the International Trade of Endangered 
Species (CITES)) were appropriate. Because white marlin had medium 
productivity, the BRT used logic set forth by AFS to determine that 
biomass at or less than 1 percent of carrying capacity (i.e., B/K <= 1) 
combined with other biological benchmarks would be an appropriate 
status-based listing threshold. At this time we have no reason to 
disagree with this logic and agree that AFS standards are appropriate 
as they were developed for marine fishes.
    The BRT considered many factors in determining that, for white 
marlin, the proper application of the ESA criterion ``foreseeable 
future'' is 10 - 15 years. We have examined the factors identified by 
the BRT and further considered particular threats, life-history 
characteristics, and population modeling to determine a projected 
period by which to consider the species' status and threats. It is 
consistent with the purpose of the ESA that the time frame for the 
foreseeable future be adequate to provide for the conservation and 
recovery of threatened species and the ecosystems upon which they 
depend. As suggested by IUCN and CITES, the period of time required to 
replace a spawning individual can be considered to assess risk. The BRT 
estimated that it would take approximately 3-5 years to replace a 
spawning white marlin; extrapolating to include three generations (the 
IUCN forecast period) would be equivalent to about 10 - 15 years. 
Notably, maximum age of white marlin is unknown and aging techniques 
are still being developed; a single tagged specimen has been reported 
at liberty for 18 years. Considering the best available information, we 
concur with the BRT that the foreseeable future for this species is 
within 15 years.
    The BRT determined that the major threat to the white marlin is 
fishing mortality. Therefore, it established a two-tiered metric to 
assess status of white marlin: first establish if B/K was at or less 
then 0.01, then consider other additive criteria that would be 
indicative of excessive fishing pressure. If B/K is greater than 0.01, 
then the white marlin is not in danger of extinction and is not likely 
to become so in the foreseeable future. The additive criteria included 
population parameters such as population structure by age class, 
population size and biomass, depensation; distribution through 
geographic range; and rate of fishing mortality. The BRT used this 
tiered approach realizing that B/K was an indicator of the overall 
viability of the population, but other criteria were also important.
    We do not disagree with using biomass relative to carrying capacity 
as a metric by which to indicate status of a species; by statute we are 
to use the best available scientific and commercial information 
available, and we believe the 2006 ICCAT stock assessment presents that 
information. Carrying capacity (i.e., K) is a metric used in stock 
assessments to indicate the maximum number of fish that can live in an 
area; subsequent fishing removes fish, and the biomass (total weight or 
volume of a species in a given area) is reduced below carrying 
capacity. In the case of white marlin, stock assessment reference 
points and models expressed with reference to carrying capacity were 
widely used and thus made a convenient status metric. We also agree 
with the BRT's approach of additive metrics: these other status 
indicators (i.e., decreasing trend in absolute population size or 
biomass; reduced range; loss of observed size classes or other evidence 
of recruitment failure; sustained increase in fishing mortality; 
increasingly rare interactions; or depensation) are sensitive to 
fishing pressure that complement the overall criterion of B/K with 
other indices. While this combination of indicators is potentially less 
conservative than a single population size-based threshold, it is more 
scientifically rigorous and, we believe, a much sounder basis for this 
listing decision.
    For white marlin, available evidence indicates neither the carrying 
capacity indicator nor the additive fishing pressure indicators are 
currently applicable. We used the population modeling requested by the 
BRT to evaluate the risk of future white marlin population decline 
based on fishing mortality, as that is considered the major threat to 
white marlin. These models assessed the probability of population 
decline to less than 1 percent of carrying capacity at varying fishing 
mortality levels. Using a fishing mortality rate (i.e., F) of 0.16, 
which is much greater than the current rate of 0.09, results of the 
Bayesian Schaefer production model indicated that the probability of 
the white marlin population falling below a B/K of 0.01 within 15 
years, and even the next 30 years was 0.

Consideration of Other Conservation Efforts

    ESA section 4(b)(1)(A) requires the Secretary, in making listing 
determinations, to take into account those efforts, if any, being made 
by any state or foreign nation, or any political subdivision of such, 
to protect species, whether by predator control, protection of habitat 
and food supply, or other conservation practices, within any area under 
its jurisdiction, or on the high seas. The ICCAT manages white marlin 
throughout the Atlantic Ocean. Resolutions and recommendations are in 
place to reduce and limit landings of white marlin, encourage voluntary 
release of live billfish in a manner to maximize survival, rebuild 
white marlin, and conduct periodic stock assessments. Meanwhile, the 
ICCAT Compliance Committee continues to make official determinations of 
non-compliance and to report at the annual ICCAT meetings.
    ESA section 4(b)(1)(B) requires us to give consideration to species 
which have been designated as requiring protection from unrestricted 
commerce by any foreign nation, or pursuant to any international 
agreement; or identified as in danger of extinction, or likely to 
become so within the foreseeable future, by any state agency or any 
agency of a foreign nation that is responsible for the conservation of 
the species. We are not aware of any such special protections or 
designations. White marlin are not afforded any protective measures or 
special status via the CITES or the IUCN).


    We have reviewed the status of Atlantic white marlin, considering 
the best scientific and commercial data available. We have given 
consideration to conservation efforts and special designations for 
white marlin by states and foreign nations. The biological status of 
the species and consideration of the ESA section 4(a)(1) factors 
indicate that the species is not in danger of extinction throughout all 
or a significant portion of its range, nor is it likely to become so in 
the foreseeable

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future. We believe that Atlantic white marlin does not meet the ESA 
definition of an endangered or threatened species; therefore, the 
listing of Atlantic white marlin under the ESA is not warranted.


    White Marlin Biological Review Team. 2007. Atlantic White Marlin 
Status Review. Report to National Marine Fisheries Service, Southeast 
Regional Office. December 10, 2007. 88 pp.

    Authority: 16 U.S.C. 1531 et seq.

    Dated: December 28, 2007.
William T. Hogarth,
Assistant Administrator for Fisheries, National Marine Fisheries 
[FR Doc. E7-25643 Filed 1-3-08; 8:45 am]