[Federal Register Volume 82, Number 165 (Monday, August 28, 2017)]
[Notices]
[Pages 40793-40796]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2017-18169]


=======================================================================
-----------------------------------------------------------------------

DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

[FWS-R8-ES-2017-N084; FF08EVEN00-FXFR1337088SSO0]


Marine Mammal Protection Act; Stock Assessment Report for the 
Southern Sea Otter in California

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of availability; response to comments.

-----------------------------------------------------------------------

SUMMARY: In accordance with the Marine Mammal Protection Act of 1972, 
as amended (MMPA), and its implementing regulations, we, the U.S. Fish 
and Wildlife Service (Service), announce that we have revised our stock 
assessment report (SAR) for the southern sea otter stock in the State 
of California, including incorporation of public comments. We now make 
our final revised SAR available to the public.

ADDRESSES: Document Availability: You may obtain a copy of the SAR from 
our Web site at https://www.fws.gov/ventura/endangered/species/info/sso.html. Alternatively, you may contact the Ventura Fish and Wildlife 
Office, U.S. Fish and Wildlife Service, 2493 Portola Road, Suite B, 
Ventura, CA 93003; telephone: 805-644-1766.

FOR FURTHER INFORMATION CONTACT: For information on the methods, data, 
and results of the stock assessment, contact Lilian Carswell by 
telephone (805-677-3325) or by email ([email protected]). Persons 
who use a telecommunications device for the deaf (TDD) may call the 
Federal Relay Service at 800-877-8339.

SUPPLEMENTARY INFORMATION: We are announcing the availability of the 
final revised SAR for the southern sea otter (Enhydra lutris nereis) 
stock in the State of California.

Background

    Under the MMPA (16 U.S.C. 1361 et seq.) and its implementing 
regulations

[[Page 40794]]

in the Code of Federal Regulations (CFR) at 50 CFR part 18, we regulate 
the taking; import; and, under certain conditions, possession; 
transportation; purchasing; selling; and offering for sale, purchase, 
or export, of marine mammals. One of the goals of the MMPA is to ensure 
that stocks of marine mammals occurring in waters under U.S. 
jurisdiction do not experience a level of human-caused mortality and 
serious injury that is likely to cause the stock to be reduced below 
its optimum sustainable population (OSP) level. OSP is defined under 
the MMPA as ``the number of animals which will result in the maximum 
productivity of the population or the species, keeping in mind the 
carrying capacity of the habitat and the health of the ecosystem of 
which they form a constituent element'' (16 U.S.C. 1362(9)).
    To help accomplish the goal of maintaining marine mammal stocks at 
their OSPs, section 117 of the MMPA requires the Service and the 
National Marine Fisheries Service (NMFS) to prepare a SAR for each 
marine mammal stock that occurs in waters under U.S. jurisdiction. Each 
SAR must include:
    1. A description of the stock and its geographic range;
    2. A minimum population estimate, current and maximum net 
productivity rate, and current population trend;
    3. An estimate of annual human-caused mortality and serious injury 
by source and, for a strategic stock, other factors that may be causing 
a decline or impeding recovery of the stock;
    4. A description of commercial fishery interactions;
    5. A categorization of the status of the stock; and
    6. An estimate of the potential biological removal (PBR) level.
    The MMPA defines the PBR as ``the maximum number of animals, not 
including natural mortalities, that may be removed from a marine mammal 
stock while allowing that stock to reach or maintain its [OSP]'' (16 
U.S.C. 1362(20)). The PBR is the product of the minimum population 
estimate of the stock (Nmin); one-half the maximum 
theoretical or estimated net productivity rate of the stock at a small 
population size (Rmax); and a recovery factor 
(Fr) of between 0.1 and 1.0. This can be written as:

PBR = (Nmin)(\1/2\ of the Rmax)(Fr)

    Section 117 of the MMPA requires the Service and NMFS to review the 
SARs (a) at least annually for stocks that are specified as strategic 
stocks, (b) at least annually for stocks for which significant new 
information is available, and (c) at least once every 3 years for all 
other stocks. If our review of the status of a stock indicates that it 
has changed or may be more accurately determined, then the SAR must be 
revised accordingly.
    A strategic stock is defined in the MMPA as a marine mammal stock 
``(A) for which the level of direct human-caused mortality exceeds the 
[PBR] level; (B) which, based on the best available scientific 
information, is declining and is likely to be listed as a threatened 
species under the Endangered Species Act of 1973 [as amended] (16 
U.S.C. 1531 et seq.) [the ``ESA''], within the foreseeable future; or 
(C) which is listed as a threatened species or endangered species under 
the [ESA], or is designated as depleted under [the MMPA]'' (16 U.S.C. 
1362(19)).

Stock Assessment Report History for the Southern Sea Otter in 
California

    The southern sea otter SAR was last revised in 2014. Because the 
southern sea otter qualifies as a strategic stock due to its listing as 
a threatened species under the ESA, the Service reviewed the stock 
assessment in 2015. The review concluded that the status had not 
changed, nor could it be more accurately determined. However, upon 
review in 2016, the Service determined that revision was warranted.
    Before releasing our draft SAR for public review and comment, we 
submitted it for technical review internally and for scientific review 
by the Pacific Regional Scientific Review Group, which was established 
under the MMPA (16 U.S.C. 1386(d)). In a December 6, 2016 (81 FR 
87951), Federal Register notice, we made our draft SAR available for 
the MMPA-required 90-day public review and comment period. Following 
the close of the comment period, we revised the SAR based on public 
comments we received (see Response to Public Comments) and prepared the 
final revised SAR. Between publication of the draft and final revised 
SARs, we have not revised the status of the stock itself (the southern 
sea otter continues to retain its status as a strategic stock). 
However, we have updated the SAR to include the most recent information 
available.

Summary of Final Revised Stock Assessment Report for the Southern Sea 
Otter in California

    The following table summarizes some of the information contained in 
the final revised SAR for southern sea otters in California, which 
includes the stock's Nmin, Rmax, Fr, 
PBR, annual estimated human-caused mortality and serious injury, and 
status:

                                 Summary--Final Revised Stock Assessment Report for the Southern Sea Otter in California
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                      Annual estimated human-
      Southern sea otter stock             NMIN            RMAX             FR              PBR        caused  mortality and          Stock status
                                                                                                           serious injury
--------------------------------------------------------------------------------------------------------------------------------------------------------
Mainland............................           3,194            0.06             0.1            9.58  Figures by specific      Strategic.
                                                                                                       source, where known,
                                                                                                       are provided in the
                                                                                                       SAR.
San Nicolas Island..................              78            0.13             0.1            0.51
                                     ----------------------------------------------------------------
    Summary.........................           3,272  ..............  ..............              10
--------------------------------------------------------------------------------------------------------------------------------------------------------

Response to Public Comments

    We received comments on the draft SAR from the Marine Mammal 
Commission (Commission), Friends of the Sea Otter, and the Humane 
Society of the United States. We present substantive issues raised in 
those comments that are pertinent to the SAR, edited for brevity, along 
with our responses below.
    Comment 1: Without adequate observer coverage to document the rate 
at which sea otters are being caught in crab and lobster gear, it is 
not possible to know if modifications to these traps should be 
required. Therefore, the Commission recommends that the Service 
collaborate with NMFS and the California Department of Fish and 
Wildlife (CDFW) to (1) establish an observer program with adequate 
coverage to obtain reliable information on the rate and circumstances 
under which sea otters are being taken in crab and lobster trap 
fisheries operating within the range of the southern sea

[[Page 40795]]

otter, or (2) implement a precautionary requirement for all trap gear 
to be modified to reduce the probability of sea otter bycatch to near 
zero.
    Response: We recognize that the probability of bycatch in trap 
fisheries will rise as the southern sea otter expands its range to the 
north, increasing overlap with the Dungeness crab fishery, and to the 
south, increasing overlap with the spiny lobster fishery and finfish 
trap fishery in southern California. We will continue to work with CDFW 
and other partners to assess the best means of testing and, if 
appropriate, implementing precautionary trap modifications in the 
fisheries that may interact with sea otters. We note that, based on 
tests that have occurred to date, relatively minor modifications to 
Dungeness crab traps (reducing the fyke opening from 4 x 9 inches (10.2 
x 22.9 cm) to 3 x 9 inches (7.6 x 22.9 cm)) would exclude most 
independent (post-weaning) sea otters while not impeding the capture of 
crabs (Hatfield et al. 2011). Comparable modifications have not been 
identified for spiny lobster traps or the large-fyke finfish traps used 
in southern California. While observer programs would increase our 
opportunity to detect bycatch, analyses indicate that high levels of 
observer effort would be required to avoid false-negative conclusions, 
even if the rate of bycatch mortality is substantial enough to reduce 
the population growth rate (Hatfield et al. 2011). We will continue to 
work with USGS, NMFS, and CDFW to explore options for assessing sea 
otter bycatch.
    Comment 2: Figure 3 in the draft SAR shows an increasing trend in 
the number of strandings as a proportion of the spring count of sea 
otters (termed ``relative mortality'' in the report), from roughly 5 
percent in the late 1980s to 12 percent in the past 4 years. The draft 
SAR attributes this pattern largely to the increase in shark-bite 
mortality at the peripheries of the southern sea otter's range. 
However, this interpretation assumes that search effort and stranding 
rates have not increased, an assumption that is not addressed in the 
report. The Service should address all of the factors that could 
explain the apparent increase in the relative number of strandings.
    Response: We have added a discussion of other factors that could 
explain the increase in the relative number of strandings and the 
relative frequency of shark-bitten carcasses.
    Comment 3: The Service should place greater emphasis on the fact 
that the ``relative mortality'' rate is an underestimate of the true 
mortality rate because a substantial portion of carcasses likely never 
strand or are never found, as has been demonstrated in this and other 
sea otter populations.
    Response: We have added text emphasizing that relative mortality is 
an index of mortality and an underestimate of the true mortality rate.
    Comment 4: An effective opportunity for public review and comment 
cannot occur if the public does not have access to all of the sources 
of information used to produce a draft stock assessment. The draft SAR 
contains numerous references to sources of information that are not 
easily available to the public. The Service should consider 
implementing a policy regarding the use of different data/information 
sources that would ensure that those sources have been reviewed and are 
easily available to the public. The Commission understands that in some 
cases the best available science has not been reviewed and published. 
In those cases, if the Service uses such information in an SAR, it 
should make the information easily available to the public.
    Response: We utilize peer-reviewed publications whenever possible. 
However, when the best available science on a topic of direct 
importance to the SAR has not yet been reviewed and published, we 
believe it is preferable to present that information to the public 
rather than to withhold it. We may cite an informal source when new 
scientific information becomes available and update the citation in a 
subsequent revision of the SAR when that information has been reviewed 
and published. We have updated several such citations in the final SAR. 
Our notice of availability (81 FR 87951; December 6, 2016) includes 
contact information, which is made available for the use of anyone 
wishing to obtain additional information, including any of the sources 
of information referenced in the SAR.
    Comment 5: In accordance with section 117(c)(1)(A) of the MMPA, the 
Service may review a stock's status annually and update its stock 
assessment report only when it considers it appropriate to do so. 
However, given the rapid changes that are ongoing within the current 
and historical range of the southern sea otter, the failure of the 
population to expand its range significantly in the past 20 years, and 
the sudden shifts in count trajectories in different parts of the range 
over the last few years, the Commission recommends that the U.S. Fish 
and Wildlife Service make its stock assessment reviews available yearly 
to the appropriate Scientific Review Group (SRG) and the Commission, at 
a minimum, from this point forward.
    Response: We typically provide a presentation to the Pacific SRG on 
the status of the southern sea otter even in years when we determine 
that a revision of the SAR is not warranted. We will continue to make 
such presentations and, from this point forward, will provide our 
reasoning to the Pacific SRG and Commission in years when we determine 
that a revision of the SAR is not warranted.
    Comment 6: ``Stock definition and geographic range'' must be 
expanded to include the importance of range expansion in southern sea 
otter survival and recovery.
    Response: We have added text emphasizing the importance of range 
expansion to recovery of the southern sea otter and referencing Service 
documents that discuss the subject in greater detail.
    Comment 7: ``Current population trend'' should be revised to 
include the declining trend in the southern portion of the range due to 
shark bite mortality.
    Response: We have added text that describes the regional declining 
trends and their relationship to increases in shark bite mortality.
    Comment 8: The SAR should identify shark bite mortality as a factor 
impeding the recovery of the southern sea otter and encourage the close 
monitoring of this significant trend. The Service should confirm that 
delisting would not be appropriate even if the delisting threshold of 
3,090 animals is met for 3 consecutive years unless the threat posed by 
shark bites has been addressed.
    Response: We will continue to monitor shark-bite mortality through 
the stranding and necropsy programs led by USGS and CDFW, and we have 
added text that makes more explicit the relationship between high rates 
of shark-bite mortality and the lack of range expansion. However, we do 
not believe that the SAR is the appropriate document in which to 
discuss threats to the species in comprehensive detail or to make 
recommendations regarding delisting. We will update our assessment of 
the status of the southern sea otter in relation to the five threat 
factors described in section 4(a)(l) of the ESA in the next 5-year 
review.
    Comment 9: ``Status of Stock'' should be discussed in relation to 
the five statutory delisting criteria and the recovery plan, in 
addition to optimum sustainable population (OSP) under the MMPA, noting 
that OSP has been discussed for the California coast but should also be 
considered on a range-wide basis, after accounting for the possible 
need to avoid interbreeding

[[Page 40796]]

between northern and southern sea otters.
    Response: As noted in our response to Comment 8, we do not believe 
that the SAR is the appropriate document in which to discuss threats to 
the species in comprehensive detail. However, we have added text that 
references our most recent 5-year review (Service 2015). We have also 
added text clarifying that a formal determination of OSP will be 
developed with reference to the entire historic range of the 
subspecies.
    Comment 10: ``Habitat issues'' should be revised to include (1) the 
spatial structure of southern sea otter habitat and its contribution in 
preventing recovery of the species and (2) a detailed discussion of the 
risk posed by oil spills.
    Response: We have added text clarifying the relationship between 
the pace of range expansion, the spatial structure of sea otter 
habitat, and oil spill risk. However, as noted in our response to 
Comments 8 and 9, we do not believe that the SAR is the appropriate 
document in which to discuss threats to the species in comprehensive 
detail. We address oil spill risk and the effects of the spatial 
structure of sea otter habitat on population growth in our most recent 
5-year review (Service 2015). We will update our assessment of these 
and other factors in the next 5-year review.
    Comment 11: There are recent reports of what appear to be 
increasing rates of shooting-related incidents. For example, in 2016 
alone there were reports of at least three sea otters being shot. In 
2015, a California man was sentenced for shooting an air rifle at sea 
otters. While these incidents are more recent than the time period of 
the SAR, which is largely through 2014, they do represent the most 
recent available information and should be considered for inclusion 
since the Service provided information on some deaths as recently as 
2016.
    Response: We have added text stating that three sea otters died of 
gunshot wounds in 2016. However, we do not include these mortalities in 
the current calculation of mean annual mortality because they occurred 
outside the 5-year analysis window (2011-2015).

Additional References Cited

Chinn, S.M., M.A. Miller, M.T. Tinker, M.M. Staedler, F.I. Batac, 
E.M. Dodd, L.A. Henkel. 2016. The high cost of motherhood: end-
lactation syndrome in southern sea otters. Journal of Wildlife 
Diseases 52:307-318. doi: 10.7589/2015-06-158.
Lafferty, K.D. M.T. and Tinker. 2014. Sea otters are recolonizing 
southern California in fits and starts. Ecosphere 5:50. http://dx.doi.org/10.1890/ES13-00394.1.
Tinker, M.T. 2014. Models and sea otter conservation. Pp. 257-300 in 
Larson, S., G. VanBlaricom and J. Bodkin, eds., Sea Otter 
Conservation. New York: Elsevier.
Tinker, M.T., and B.B. Hatfield. 2016. California sea otter (Enhydra 
lutris nereis) census results, spring 2016. U.S. Geological Survey 
Data Series 1018. 10 pp. http://dx.doi.org/10.3133/ds1018.

Authority

    The authority for this action is the Marine Mammal Protection Act 
of 1972, as amended (16 U.S.C. 1361 et seq.)

    Dated: July 26, 2017.
Gregory Sheehan,
Acting Director, U.S. Fish and Wildlife Service.
[FR Doc. 2017-18169 Filed 8-25-17; 8:45 am]
 BILLING CODE 4333-15-P