[Federal Register Volume 78, Number 219 (Wednesday, November 13, 2013)]
[Notices]
[Pages 68032-68037]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2013-27180]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[Docket No. 1206013325-3912-03]
RIN 0648-XA983


Endangered and Threatened Wildlife; Notice of 12-Month Finding on 
a Petition To List the Sperm Whale (Physeter macrocephalus) as an 
Endangered or Threatened Distinct Population Segment (DPS) in the Gulf 
of Mexico

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

ACTION: Status review; notice of finding.

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SUMMARY: We, NMFS, announce a 12-month finding on a petition to list 
the sperm whale (Physeter macrocephalus) in the Gulf of Mexico as an 
endangered or threatened distinct population segment (DPS) under the 
Endangered Species Act of 1973 as amended (ESA). We conducted a review 
of the status of this population, as described below. Based on the best 
available scientific and commercial information, we find that the 
petitioned action is not warranted.

DATES: The finding announced in this notice was made on November 13, 
2013.

ADDRESSES: Information used to make this finding is available for 
public inspection by appointment during normal business hours at NMFS 
Headquarters, Protected Resources Office, 1315 East-West Highway, 
Silver Spring, MD 20910. This file includes the information provided by 
the public and scientific and commercial information gathered for the 
status review. The petition and a list of the references we used can 
also be found at http://www.nmfs.noaa.gov/pr/.htm.

FOR FURTHER INFORMATION CONTACT: Marta Nammack, NMFS, Office of 
Protected Resources, (301) 427-8469.

SUPPLEMENTARY INFORMATION: On December 9, 2011, we received a petition 
from WildEarth Guardians to list the sperm whale (Physeter 
macrocephalus) population in the Gulf of Mexico as an endangered or 
threatened Distinct Population Segment (DPS) under the Endangered 
Species Act (ESA); sperm whales are currently listed as a single 
endangered species throughout their global range (35 FR 8495; June 2, 
1970). The petitioner also requested designation of critical habitat 
concurrent with the listing.
    After reviewing the petition, the literature cited in the petition, 
and other literature and information available in our files, we found 
that the petition met the requirements of the regulations under 50 CFR 
424.14(b)(2) and determined that the petition presented substantial 
information indicating that the petitioned action may be warranted (78 
FR 19176; March 29, 2013). At that time, we commenced a status review 
of the sperm whale in the Gulf of Mexico and solicited information 
pertaining to the population. Section 4(b)(3)(B) of the ESA requires 
that when a petition to revise the List of Endangered and Threatened 
Wildlife and Plants is found to present substantial scientific and 
commercial information, we make a finding on whether the petitioned 
action is (a) not warranted, (b) warranted, or (c) warranted but 
precluded from listing by other pending proposals of higher priority. 
This finding is to be made within 12 months of the date the petition 
was received, and the finding is to be published promptly in the 
Federal Register.
    There are two key tasks associated with conducting an ESA status 
review. The first is to determine whether the petitioned entity 
qualifies as one or more species under the ESA. The ESA defines the 
term ``species'' to include ``any distinct population segment of any 
species of vertebrate fish or wildlife which interbreeds when mature.'' 
If the petitioned entity qualifies as a species, the second task is to 
conduct an extinction risk assessment to determine whether the species 
is threatened or endangered. The ESA defines the term ``endangered 
species'' as ``any species which is in danger of extinction throughout 
all or a significant portion of its range.'' The term ``threatened 
species'' is defined as ``any species which is likely to become 
endangered within the foreseeable future throughout all or a 
significant portion of its range.'' Thus, we interpret an ``endangered 
species'' to be one that is presently in danger of extinction. A 
``threatened species,'' on the other hand, is not presently in danger 
of extinction, but is likely to become so in the foreseeable future 
(that is, at a later time). In other words, the primary statutory 
difference between a threatened and endangered species is the timing of 
when a species may be in danger of extinction, either presently 
(endangered) or in the foreseeable future (threatened).

Species Background

    The sperm whale (Linnaeus, 1758) is listed as an endangered species 
under the ESA. It was first listed under the precursor to the ESA, the 
Endangered Species Conservation Act of 1969, and remained on the list 
of threatened and

[[Page 68033]]

endangered species after the passage of the ESA in 1973 (35 FR 18319; 
December 2, 1970). Whaling was the main reason for listing the sperm 
whale. Commercial whaling for this species ended in 1988 with the 
implementation of a moratorium against whaling by the International 
Whaling Commission (IWC). While whaling was eliminated by the IWC 
whaling moratorium, several potential threats remain, as discussed in 
the sperm whale recovery plan (NMFS, 2010a). Sperm whales are deep and 
prolonged divers and use the entire water column, even in very deep 
areas. Most sperm whales are found in very deep waters (>3,000 m), but 
they generally feed between 500-1,000 m where most of their prey is 
found. Sperm whales feed primarily on large- and medium-sized squid, 
but the list of documented food items is fairly long and diverse, 
including other cephalopods and medium-and large-sized demersal fish, 
such as rays, sharks, and many teleosts (Berzin, 1972; Clarke 1977, 
1980; Rice, 1989). The diet of large males in some areas, especially in 
high northern latitudes, is dominated by fish (Rice, 1989). Lockyer 
(1981) estimated sperm whales consumed about 3.0-3.5 percent of their 
body weight per day.
    Sperm whales are perhaps the most widely distributed mammal species 
on Earth. The social organization of most mammals is characterized by 
female philopatry and male dispersal. Groups of females and juveniles 
are found mainly at low latitudes, while males reach polar waters, 
returning to tropical and subtropical waters to breed. Sperm whales are 
organized in groups in which females (some related to each other and 
some not) travel with their sub-adult offspring. Mature female and 
immature sperm whales of both sexes are found in more temperate and 
tropical waters from the equator to around 45[ordm]N throughout the 
year. Adult males will move extensively, even to polar waters, and then 
return to tropical and subtropical waters.
    Sperm whales mature slowly and can live to ages in excess of 60 
years (Rice, 1989). Females usually begin ovulating at 7-13 years of 
age and usually conceive at about age 9 (Rice, 1989). Maturation in 
males usually begins in this same age interval, but most individuals do 
not become fully mature until their twenties. In the North Atlantic 
Ocean, the peak breeding season for sperm whales occurs during the 
spring (March/April to June), although some mating activity occurs 
December to August. In the South Atlantic the peak breeding season is 
presumed to occur in the austral spring. During mating seasons, prime 
bulls in their late twenties and older rove among groups of females. 
Because females within a group often come into estrus synchronously, 
the males need not remain with the females for the breeding season to 
achieve maximal breeding success (Best and Butterworth, 1980) and their 
association with a group can be as brief as several hours. Gestation 
lasts well over a year, with credible estimates of the normal duration 
ranging from 15 months to more than a year and a half. Lactation lasts 
at least 2 years, and the inter-birth-interval is 4-6 years (Best et 
al., 1984) for prime-aged females. Female sperm whales rarely become 
pregnant after the age of 40 (Whitehead, 2003). Two particular aspects 
of the sperm whale's reproductive biology are relevant to recovery. 
First, the maximal rate of increase in reproduction is very low, 
perhaps no more than one or two percent per year. Second, selective 
killing of large males by modern whaling could have had the residual 
effect of reducing reproductive rates (Whitehead et al., 1997).

Status Review

    Our 90-day finding accepting the petition solicited information 
from the public and initiated a status review of the sperm whale in the 
Gulf of Mexico (GOM) to gather any additional information to inform our 
review of the petitioned action and our application of the DPS policy. 
We reviewed the best available information, and we conducted a DPS 
analysis to determine whether the GOM population of the sperm whale 
qualifies as a DPS under the ESA. Here we review the best available 
information on physical, physiological, ecological, and behavioral 
factors to determine whether the GOM population is discrete.

Are sperm whales in the Gulf of Mexico discrete from other sperm whale 
populations?

    The ESA provides for listing species, subspecies, or DPSs of 
vertebrate species. When we evaluate a petition to list an entity as 
threatened or endangered under the ESA, we must first determine whether 
the petitioned entity qualifies as a species under the ESA. This 
petition argues that the Gulf of Mexico sperm whale population meets 
the requirements for being identified as a DPS and requests we list 
sperm whales in the Gulf of Mexico as a threatened or endangered DPS.
    Our joint NMFS-U.S. Fish and Wildlife Service (USFWS) Policy on 
Recognition of Distinct Vertebrate Population Segments under the 
Endangered Species Act (DPS policy) (61 FR 4722; February 7, 1996) 
identifies 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 species to which it 
belongs. A population segment of a vertebrate species may be considered 
discrete if it satisfies either one of the following conditions: (1) It 
is markedly separated from other populations of the same taxon as a 
consequence of physical, physiological, ecological, or behavioral 
factors. Quantitative measures of genetic or morphological 
discontinuity may provide evidence of this separation; or (2) it is 
delimited by international governmental boundaries within which 
differences in control of exploitation, management of habitat, 
conservation status, or regulatory mechanisms exist that are 
significant in light of section 4(a)(1)(D) of the ESA. If a population 
segment is considered discrete by one or more of the above conditions, 
its biological and ecological significance will then be considered in 
light of Congressional guidance (see Senate Report 151, 96th Congress, 
1st Session) that the authority to list DPSs be used ``. . . 
sparingly'' while encouraging the conservation of genetic diversity. 
The DPS policy directs us to consider available scientific evidence of 
the discrete population segment's importance to the taxon to which it 
belongs. This consideration may include, but is not limited to, the 
following: (1) Persistence of the discrete population segment in an 
ecological setting unusual or unique for the taxon; (2) evidence that 
loss of the discrete population segment would result in a significant 
gap in the range of a taxon; (3) evidence that the discrete population 
segment represents the only surviving natural occurrence of a taxon 
that may be more abundant elsewhere as an introduced population outside 
its historic range; or (4) evidence that the discrete population 
segment differs markedly from other populations of the species in its 
genetic characteristics.

DPS Analysis

    To determine if the sperm whale in the GOM meets the DPS criteria, 
we evaluate the best available information to determine whether sperm 
whales in the Gulf of Mexico are markedly separated as a consequence of 
physical, physiological, ecological, or behavioral factors from other 
populations of the sperm whale.

[[Page 68034]]

    Genetics--An examination of the best available genetic information 
reveals that, although there is strong mtDNA evidence of population 
structuring indicating differences between the GOM population and sperm 
whales in the northwest Atlantic, this is not coupled with nDNA 
evidence that would indicate that males from the GOM are genetically 
different from males in the northwest Atlantic. Physically mature male 
sperm whales typically range over huge distances on their own (Best, 
1979; Rice, 1989; Whitehead, 1993; Whitehead and Weilgart, 2000; Teloni 
et al., 2008). In contrast to females, males disperse from their natal 
units at a mean estimated age of 6 years, when they migrate slowly into 
higher latitudes prior to attaining sexual maturity at 18-21 years 
(Whitehead and Weilgart, 2000). This is re[fllig]ected in high 
variability and a lack of geographical structure in nDNA relative to 
mtDNA (Lyrholm et al., 1999).
    There are statistically significant patterns of mtDNA 
differentiation between oceans (Engelhaupt, 2004; SWSS, 2008; 
Engelhaupt et al., 2009; NMFS, 2010a); however, studies examining nDNA 
reveal either no significant (Lyrholm et al., 1999) or low (Bond, 1999) 
degrees of population structuring between oceans. Engelhaupt et al. 
(2009) suggest that the discrepancy between mtDNA and nDNA 
differentiation may reflect sex biased dispersal, and male mediated 
gene flow may connect geographically isolated regions on an oceanic 
scale. Their analysis of nDNA showed no significant difference between 
whales sampled in the GOM and those from other areas of the North 
Atlantic, indicating that mature males move in and out of the GOM. The 
results of the Engelhaupt et al. (2009) study indicate that population 
structuring is different for mtDNA compared with population structuring 
for nDNA.
    At best, mtDNA evidence suggests that females are philopatric; 
however, mtDNA does not alone describe population structure. Because 
mtDNA is maternally inherited, differences in mtDNA haplotypes between 
populations do not necessarily mean that the populations are 
substantially reproductively isolated from each other because they do 
not provide any information on males. Due to the wide ranging nature of 
mature male sperm whales, males from one population may breed with 
females from other populations. We have indicated in other status 
reviews that mtDNA data may indicate that populations are discrete, but 
in species where female and male movement patterns differ, nDNA data 
may indicate that the populations are homogeneous (see e.g., loggerhead 
sea turtle, 68 FR 53947, September 15, 2003 at 53950-51 and Conant et 
al., 2009, at 18, 22, 25-28; southern resident killer whale, Krahn et 
al., 2002, at 23-30). As noted in SWSS (2008), a male sperm whale 
tagged in 2002 moved into the North Atlantic for more than 2 months, 
providing the first evidence that the GOM population may not be a stock 
isolated from the North Atlantic (SWSS, 2008; Waring et al., 2012). Its 
return to the GOM included an extended stay off the northwest Cuban 
coast, and it summered in two different regions of the upper GOM and 
visited the Gulf of Campeche twice (SWSS, 2008). While some may view 
this as support for separate stocks in the GOM and the North Atlantic, 
SWSS (2008) notes that few males were sampled in the GOM. Because the 
tags were deployed from June to early August, more individuals were 
tracked during the summer months (SWSS, 2008). Therefore, it is likely 
that mature males were not in the GOM at this time, as they spend most 
of their time in colder waters at high latitudes and only visit 
tropical waters to reproduce (Best 1979; Whitehead and Arnbom 1987; 
Whitehead 2003, as cited in SWSS (2008)).
    The fact that males move in and out of the GOM and interbreed with 
females from other populations when mature, as evidenced by the 
homogeneity of the nDNA, indicates that the GOM population is not 
markedly separated from other populations in the Atlantic Ocean. 
Engelhaupt et al. (2009) demonstrate that a single, undivided genetic 
population of sperm whales is found from the GOM to at least northern 
Europe. As we have summarized here, the best available genetic 
information indicates that sperm whales in the GOM are not discrete 
from other sperm whale populations.
    Vocalization--We next examined information on codas. Sperm whale 
social structure is complex, with females, calves, and immature animals 
of both sexes living in relatively stable social ``units'' containing 
on average 11-12 animals that persist for decades (Rendell and 
Whitehead, 2004). These sperm whale social groups communicate via 
codas: Repeated stereotyped sequences of 3-40 broadband (0-16 kHz) 
clicks generally heard during periods of socializing (Watkins and 
Schevill, 1977). Codas are shared among individuals of a social unit 
and are considered to be primarily for intra-group communication 
(Weilgart and Whitehead, 1997; Rendell and Whitehead, 2004). These 
distinctive, short, patterned series of clicks are associated with 
social behavior and interactions within social groups (Weilgart and 
Whitehead, 1993).
    Significant differences in vocalization or coda repertoire exist 
amongst smaller social groups or ``units'' of sperm whales, and this 
variation amongst social units or groups is commonplace for sperm 
whales (Weilgart and Whitehead, 1997; Rendell and Whitehead, 2004). 
Differences in vocalization are culturally transmitted by the 
matrilineal line, and there is a difference between geographical sperm 
whale variation in codas (macrogeographic) and coda ``dialects'' 
(microgeographic) (Mundinger, 1982). In a study of sperm whales in the 
southern Pacific Ocean, Weilgart and Whitehead (1997) found that the 
sperm whale groups they encountered had distinctive dialects in coda 
usage based on analyses of interclick intervals (ICIs), the time 
intervals between clicks in a coda, standardized to total coda length. 
The group-specific dialects that are found in sperm whales have even 
been deemed as similar to those which occur in killer whale ``vocal 
clans'' (Weilgart and Whitehead, 1997; Rendell and Whitehead, 2003).
    Codas and mtDNA have been linked; a study of six sperm whale groups 
revealed a clear link between mtDNA and coda repertoire as groups with 
similar mtDNA tended to have similar coda usage dialects (Whitehead et 
al., 1998). These results indicate codas are transmitted across 
generations matrilineally. Whitehead et al. (1998) suggested vertical 
cultural transmission (offspring learn codas from their mothers) as the 
best explanation for this pattern. This may reflect the mtDNA 
information presented above suggesting population structure, without 
consideration of the nDNA. The sperm whale seismic study (SWSS, 2008) 
cited in the petition found variation in vocalization between the north 
central GOM and the northwest GOM. Because there is evidence of 
different types of coda variation (i.e., macrogeographic versus 
microgeographic dialects) within the GOM, communication is passed down 
from the mother, and adult male sperm whales travel outside the Gulf of 
Mexico, the communication difference between GOM sperm whales and sperm 
whales from other populations does not indicate sperm whales in the GOM 
are ``markedly'' separate.
    Group size--While group size in the GOM is smaller on average than 
in other oceans, group size is variable throughout their global range. 
The fact that group sizes are similar to those in the Caribbean and 
smaller than group sizes in some other oceans (SWSS,

[[Page 68035]]

2008) does not show a ``marked'' separation from other sperm whale 
group sizes. Christal et al. (1998) note that estimated social unit 
size in the Galapagos, for example, ranged from 3 to 24 individuals and 
presented evidence of splitting and merging of units and of transfer of 
individuals between units. The considerable variation in unit size 
(perhaps caused by demographic processes) suggests that the benefits of 
remaining in a social unit usually outweigh selection for some optimal 
unit size (Christal et al., 1998). Richter et al. (2008) note that it 
could be argued that differences in ecological conditions in which 
various sperm whale populations live are reflected in the parameters of 
their social behavior, such as group size and association rate (Richter 
et al., 2008). The best available evidence does not indicate that sperm 
whale group size in the GOM is different from all other populations of 
the sperm whale.
    Whale size--Mean size of sperm whales in the GOM (8.5 m) has been 
reported to be smaller than that of other sperm whale populations 
(e.g., 10 m for the Gulf of California population) (SWSS, 2008). While 
photographic data on known males and sound pulse studies showed that 
those measured in the GOM were smaller than breeding males elsewhere 
(Jaquet et al., 2006; Antunes et al., 2006), no mature males have been 
observed in the GOM. This only confirms that younger male whales that 
have recently departed from their mothers are smaller than those at 
full maturity, which is not noteworthy. Older males, which apparently 
only pass through the GOM for breeding, are larger than the younger 
males that have not yet migrated out of the GOM. Further, whale size 
data from these studies have never been normalized to account for age, 
so a reliable comparison cannot be made. Finally, Jochens et al. (2008) 
argue that female/adolescent size differences among sperm whale 
populations may be the result of nothing more than differences in prey, 
suggesting that ``it is possible that the population studied is smaller 
because smaller animals may prefer the shallower waters relative to 
their diving ability and/or availability of suitable prey.'' Whales may 
assort themselves by water depths to match their body sizes. Finally, 
even if GOM whales are a little smaller on average than other 
populations of sperm whale, such a modest difference is not sufficient 
to demonstrate that the GOM population is ``markedly separated'' from 
other sperm whale populations.
    International boundaries--In examining whether a population is 
discrete based on international governmental boundaries, we are to 
examine differences in the control of exploitation, management of 
habitat, conservation status, or regulatory mechanisms exist that are 
significant in light of section 4(a)(1)(D) of the ESA. Section 
4(a)(1)(D), the inadequacy of existing regulatory mechanisms, is one of 
the five factors we must evaluate to determine whether to list a 
species. We did not find any information pointing to significant 
differences in control of exploitation, management of habitat, 
conservation status, or regulatory mechanisms between the population of 
sperm whales in the GOM and any other particular population of the 
sperm whale such that the population of the sperm whale in the GOM 
could be considered discrete from a sperm whale population outside of 
the GOM. The ESA extends prohibitions against take of endangered 
species by any person subject to the jurisdiction of the United States 
within the United States, its territorial waters, or on the high seas. 
While the ESA may provide less protection to species under the 
jurisdiction of other countries, these differences in ESA protections 
apply for any sperm whale population that spends time in waters of the 
United States, including sperm whales within the GOM because Mexican 
waters are also outside of U.S. jurisdiction. Therefore, we cannot rely 
on differences in ESA protections for sperm whales within the GOM and 
outside of the GOM as support for the discreteness criterion of the DPS 
policy.
    With regard to other regulatory mechanisms, the United States and 
Mexico are both parties to the Convention on the International Trade in 
Endangered Species of Wild Fauna and Flora (CITES), and the sperm whale 
is listed on Cites Appendix I, which means, aside from exceptional 
circumstances, commercial trade of products of sperm whales across 
international borders of member countries is prohibited. However, many 
other countries within the range of the sperm whale are parties to 
CITES and, therefore, are subject to the same prohibitions. The United 
States and Mexico are also members of the International Whaling 
Commission (IWC) and have therefore adopted the IWC's General 
Principles for Whalewatching, which include: Managing the development 
of whalewatching to minimize the risk of adverse impacts; designing, 
maintaining, and operating platforms to minimize the risk of adverse 
impacts on cetaceans, including disturbance from noise; and allowing 
the cetaceans to control the nature and duration of interactions. But 
again, many other countries are members of the IWC, too. We find that 
regulatory mechanisms with respect to sperm whales in the GOM do not 
differ significantly from regulatory mechanisms with respect to other 
sperm whale populations. Therefore, we find that the GOM population is 
not discrete from other populations of the sperm whale based on 
differences in control of exploitation, management of habitat, 
conservation status, or regulatory mechanisms.
    Relation between ``stock'' and DPS--NMFS has identified the 
Northern Gulf of Mexico sperm whale population as a stock for purposes 
of the Marine Mammal Protection Act (MMPA) http://www.nmfs.noaa.gov/pr/pdfs/sars/ao2012whsp-gmxn.pdf (Waring et al. (2012)). However, a stock 
under the MMPA is not equivalent to a DPS under the ESA. Under the 
MMPA, a ``population stock'' or ``stock'' is ``a group of marine 
mammals of the same species or smaller taxa in a common spatial 
arrangement that interbreed when mature'' (16 U.S.C. 1362(11)). The 
term ``stock'' is interpreted consistent with Congressional findings 
and policy: ``. . . the primary objective of their management [of 
stocks] should be to maintain the health and stability of the marine 
ecosystem. Whenever consistent with this primary objective, it should 
be the goal to obtain an optimum sustainable population keeping in mind 
the carrying capacity of the habitat.'' 16. U.S.C. 1361(5). The 
guidelines for preparing stock assessment reports under the MMPA 
include guidelines for identifying stocks, and they note that ideally, 
a stock would be a management unit that identifies a demographically 
isolated biological population (NMFS, 2005). Demographic isolation 
means that the population dynamics of the affected group are more a 
consequence of births and deaths within the group (internal dynamics) 
rather than immigration or emigration (external dynamics) (NMFS, 2005, 
http://www.nmfs.noaa.gov/pr/pdfs/sars/gamms2005.pdf). A major goal of 
identifying stocks under the guidelines is to avoid potential for 
localized depletion where marine mammals are subject to human-caused 
mortality and serious injury.
    As described above, our joint USFWS-NMFS DPS policy contains 
different criteria for identifying a population as a DPS. The ESA's 
purpose of providing for the conservation of species and the ecosystems 
upon which they depend, along with the Congressional direction to use 
the

[[Page 68036]]

provision sparingly, guided the development of the DPS policy. The DPS 
policy requires that a population be both discrete from other 
populations and significant to the taxon to which it belongs. While in 
most circumstances we evaluate some or all of the same evidence in 
determining whether a population of marine mammals should be considered 
a stock under the MMPA or a DPS for purposes of the ESA, demographic 
independence alone does not suffice to establish a DPS. Therefore, the 
fact that the GOM population is considered a stock under the MMPA does 
not qualify the population as a DPS under the ESA.
    In the 2006 NMFS Workshop on Conservation Units of Managed Fish, 
Threatened or Endangered Species, and Marine Mammals (NOAA Tech Memo 
NMFS-OPR-37, 2008), NMFS elaborated on the distinctions:
    ``Conservation units under the ESA should be substantially 
reproductively isolated from one another to be listed under this act. 
On the other hand, objectives of the MMPA include keeping populations 
or stocks of animals above their Optimum Sustainable Populations OSP 
levels. The Magnuson-Stevens Act (MSA) allows for management units that 
may contain multiple species as members of a complex, but the concept 
of demographically independent stocks within a species is commonly used 
to determine the status of fishery resources. Thus, demographic 
independence is an appropriate basis for identifying conservation units 
(distinguishing among populations or stocks) for the MSA and MMPA.''
    ``A low amount of exchange among groups for breeding may be 
sufficient to prevent development of important genetic differences; 
however, these groups may remain demographically independent from one 
another. Therefore, it is generally expected that conservation units 
identified on the basis of reproductive isolation would be larger than 
those identified on the basis of demographic independence. Thus, 
discrete groups under the DPS policy would generally be larger than 
discrete groups identified for management under the MSA or MMPA. 
Furthermore, marine mammal biology includes internal fertilization, 
live birth, parental care, and maintenance of family groups; these 
features act as barriers to mixing among groups and help produce fine-
scale population structure.''
    While Waring et al. (2012) note that results of multi-disciplinary 
research conducted in the GOM since 2000 confirm speculation by 
Schmidly (1981) and indicate that GOM sperm whales constitute a stock 
that is distinct from other Atlantic Ocean stocks(s) (Mullin et al. 
2003; Jaquet 2006; Jochens et al. 2008), it is important to note that 
Waring et al. (2012) is a stock assessment conducted under the MMPA. A 
conclusion that northern GOM sperm whales constitute a stock under the 
MMPA does not demonstrate that the GOM population of sperm whales is a 
DPS.
    Recovery Plan and DPSs--Our Recovery Plan (NMFS, 2010a) and 5-year 
review of the sperm whale (NMFS, 2009) recognize that there may be 
potential sperm whale DPSs, but they also state that further 
information is needed to determine a global DPS structure. Further, the 
Recovery Plan did not use the criteria in the DPS policy when making 
its assertion. Neither document concluded that at this time sufficient 
evidence exists to identify any population as a DPS under the ESA. 
Further information to support this is not available.

DPS Analysis--Discreteness Conclusion

    To summarize, the best available information on genetics, size, 
behavior, and regulatory mechanisms does not indicate the sperm whales 
in the GOM are discrete from other populations of the sperm whale. The 
weight of the evidence does not indicate the GOM population of the 
sperm whale is ``markedly separated'' from other populations. While 
mtDNA analysis indicates some population structuring, nDNA analysis 
indicates that successful reproductive-mixing is occurring and that the 
GOM sperm whales are not reproductively isolated. Average size of the 
individuals and number in a group may differ throughout the range, but 
this does not indicate ``marked'' differences between sperm whales in 
the GOM and sperm whales in other geographic areas. With regard to 
behavioral differences, there is evidence that sperm whales in the GOM 
may use different codas for communication, but this differentiation is 
also seen within and between smaller social groups. We found that 
regulatory mechanisms with regard to sperm whales in the GOM do not 
differ significantly from those with regard to sperm whales in other 
areas. We believe the best available scientific and commercial 
information does not show that GOM sperm whales are ``markedly'' 
separated from other sperm whales as a consequence of physical, 
physiological, ecological, or behavioral factors.

Conclusion Regarding DPS

    On the basis of the best available information, as described above, 
we conclude the GOM population is not discrete from other sperm whale 
populations and therefore does not meet the DPS criteria. Because the 
GOM sperm whales are not discrete from other sperm whale populations, 
we do not need to determine whether the GOM population of the sperm 
whale is significant to the global taxon of sperm whale, per the DPS 
policy. In any event, even if the GOM population of the sperm whale 
qualified as a discrete population, it does not meet the significance 
criterion of the DPS policy. It does not persist in an ecological 
setting unusual or unique for the taxon, as there are other areas 
within the range of the sperm whale with similar features to the GOM 
(e.g., Mediterranean Sea, which is another semi-enclosed, partially 
land-locked, intercontinental, marginal sea (www.gulfmex.org/about-the-gulf/gulf-of-mexico-facts/).
    Loss of the GOM population would not result in a significant gap in 
the range of the sperm whale, as the range of the GOM population 
(1,500,000 sq km, www.gulfbase.org/facts.php--visited on September 27, 
2013) is only a small portion (0.47 percent) of the global range 
(317,453,000 sq km, ngdc.noaa.gov/mgg/global/etopo1_ocean_volumes.html). The GOM population is not the only surviving natural 
occurrence of the sperm whale, as the species occurs in the Pacific, 
Indian, and Atlantic oceans. Finally, as discussed above, the GOM 
population does not differ markedly from other populations of the 
species in its genetic characteristics.
    Therefore, the GOM population of the sperm whale does not qualify 
as a DPS.

Analysis of ESA Section 4(a)(1) Factors

    Because the sperm whale population in the GOM does not qualify as a 
DPS under the ESA, we did not conduct an inquiry of the factors 
identified in Section 4(a)(1) of the ESA. The sperm whale is currently 
listed globally as endangered and receiving the full protection of the 
ESA.

Finding

    We find that the GOM population of the sperm whale does not meet 
the DPS Policy criteria for qualifying as a DPS. Therefore, listing 
this population as a separate DPS under the ESA is not warranted.

Authority

    The authority for this action is the Endangered Species Act of 
1973, as amended (16 U.S.C. 1531 et seq.).


[[Page 68037]]


    Dated: November 6, 2013.
Samuel D. Rauch III,
Deputy Assistant Administrator for Regulatory Programs, performing the 
functions and duties of the Assistant Administrator for Fisheries, 
National Marine Fisheries Service.
[FR Doc. 2013-27180 Filed 11-12-13; 8:45 am]
BILLING CODE 3510-22-P