E8-12890. Marine Mammal Protection Act; Stock Assessment Report

AGENCY:

Fish and Wildlife Service, Interior.

ACTION:

Notice of availability of draft revised marine mammal stock assessment report for the southern sea otter in California; request for comments.

SUMMARY:

In accordance with the Marine Mammal Protection Act (MMPA), the Fish and Wildlife Service (Service) has developed a draft revised marine mammal stock assessment report for the southern sea otter (Enhydra lutris nereis) stock in the State of California, which is available for public review and comment.

DATES:

Comments must be received by September 8, 2008.

ADDRESSES:

Copies of the draft revised stock assessment report for the southern sea otter in California are available from the Field Supervisor, U.S. Fish and Wildlife Service, Ventura Fish and Wildlife Office, 2493 Portola Road, Suite B, Ventura, CA 93003; [phone]. It can also be viewed in Adobe Acrobat by navigating to the species information page for the southern sea otter at http://www.fws.gov/​ventura.

If you wish to submit comments on the draft revised stock assessment report for the southern sea otter in California, you may do so by any of the following methods:

1. You may mail or hand-deliver (during normal business hours) written comments to the Field Supervisor, U.S. Fish and Wildlife Service, Ventura Fish and Wildlife Office, 2493 Portola Road, Suite B, Ventura, CA 93003.

2. You may fax your comments to [phone].

3. You may send comments by electronic mail (e-mail) to fw8ssostock@ fws.gov.

SUPPLEMENTARY INFORMATION:

One of the goals of the MMPA is to ensure that stocks of marine mammals occurring in waters under the jurisdiction of the United States 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 level (OSP). OSP is defined 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.”

To help accomplish the goal of maintaining marine mammal stocks at their OSPs, section 117 of the MMPA (16 U.S.C. 1361-1407) requires the Service and the National Marine Fisheries Service (NMFS) to prepare stock assessment reports for each marine mammal stock that occurs in waters under the jurisdiction of the United States. These stock assessments are to be based on the best scientific information available and are, therefore, prepared in consultation with established regional scientific review groups. Each stock assessment must include: (1) A description of the stock and its geographic range; (2) a minimum population estimate, maximum net productivity rate, and current population trend; (3) an estimate of human-caused mortality and serious injury; (4) a description of commercial fishery interactions; (5) the status of the stock; and (6) the potential biological removal level (PBR). The PBR is defined 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.” The PBR is the product of the minimum population estimate of the stock (N_min), one-half the maximum theoretical or estimated net productivity rate of the stock at a small population size (R_max); and a recovery factor (F_r) of between 0.1 and 1.0, which is intended to compensate for uncertainty and unknown estimation errors.

Section 117 of the MMPA also requires the Service and the NMFS to review the stock assessment reports: (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.

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 potential biological removal 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.), within the foreseeable future; or (C) which is listed as a threatened or endangered species under the Endangered Species Act, or is designated as depleted under the MMPA.

A summary of the draft revised stock assessment report for southern sea otters in California is presented in Table 1. The table lists the stock's N_min, R_max, F_r, PBR, annual estimated human-caused mortality and serious injury, and status. After consideration of any public comments received, the Service will revise the stock assessment, as appropriate. We will publish a notice of availability and summary of the final stock assessment, including responses to comments we received.

In accordance with the MMPA, a list of the sources of information or public reports upon which the assessment is based is included in this notice.

Table 1.—Summary of Draft Revised Stock Assessment Report for the Southern Sea Otter in California

Stock	NMIN	RMAX	FR	PBR	Annual estimated average human-caused mortality	Stock status
Southern sea otters:
Mainland California	3,026	0.06	0.1	9	Unknown	Strategic.
Mainland California San Nicolas Island (CA)	41	0.09	0.1	0	Unknown	Strategic.

List of References

Bacon, C.E. 1994. An ecotoxicological comparison of organic contaminants in sea otters among populations in California and Alaska. M.S. thesis, University of California, Santa Cruz.

Bacon, C.E., W.M. Jarman, J.A. Estes, M. Simon, and R.J. Norstrom. 1999. Comparison of organochlorine contaminants among sea otter (Enhydra lutris) populations in California and Alaska. Environ. Toxicology and Chemistry 18(3):452-458.

Bryant, H.C. 1915. Sea otters near Point Sur. California Department of Fish and Game Bull. 1:134-135.

Cameron, G.A., and K.A. Forney. 2000. Preliminary estimates of cetacean mortality in California/Oregon gillnet fisheries for 1999. Paper SC/S2/O24 presented to the International Whaling Commission, 2000 (unpublished). 12 pp. Available from NMFS, Southwest Fisheries Science Center, P.O. Box 271, La Jolla, California, 92038, USA.

Carretta, J.V. 2001. Preliminary estimates of cetacean mortality in California gillnet fisheries for 2000. Paper SC/53/SM9 presented to the International Whaling Commission, 2001 (unpublished). 21 pp. Available from NMFS, Southwest Fisheries Science Center, P.O. Box 271, La Jolla, California, 92038, USA.

Cronin, M.A., J. Bodkin, B. Bellachey, J.A. Estes, and J.C. Patton. 1996. Mitochondrial-DNA variation among subspecies and populations of sea otters (Enhydra lutris). J. Mammal. 77:546-557.

Estes, J.A. 1990. Growth and equilibrium in sea otter populations. J. Anim. Ecol. 59:385-401.

Estes, J.A., and R.J. Jameson. 1988. A double-survey estimate for sighting probability of sea otters in California. J. Wildl. Manage. 52:70-76.

Estes, J.A., B.B. Hatfield, K. Ralls, and J. Ames. 2003. Causes of mortality in California sea otters during periods of population growth and decline. Marine Mammal Science 19(1):198-216.

Forney, K.A., S.R. Benson, and G.A. Cameron. 2001. Central California gill net effort and bycatch of sensitive species, 1990-1998. Pages 141-160 in Seabird Bycatch: Trends, Roadblocks, and Solutions, E.F. Melvin and J.K. Parrish, eds. Proceedings of an International Symposium of the Pacific Seabird Group, University of Alaska Sea Grant, Fairbanks, Alaska, 212 pp.

Hatfield, B.B., and J.A. Estes. 2000. Preliminary results of an evaluation of the potential threat to sea otters posed by the nearshore finfish trap fishery. Unpublished. 6 pp. + appendices.

Herrick, S.F., Jr., and D. Hanan. 1988. A review of California entangling net fisheries, 1981-1986. National Oceanic and Atmospheric Administration Technical Memorandum. National Marine Fisheries Service. NOAA-TM-NMFS-SWFC-108. 39 pp.

Jameson, R.J. 1989. Movements, home range, and territories of male sea otters off central California. Marine Mammal Science 5:159-172.

Jameson, R.J., and S. Jeffries. 1999. Results of the 1999 survey of the Washington sea otter population. Unpublished report. 5 pp.

Jameson, R.J., and S. Jeffries. 2005. Results of the 2005 survey of the reintroduced Washington sea otter population. Unpublished report. 6 pp.

Kannan, K., E. Perrotta, and N.J. Thomas. 2006. Association between perfluorinated compounds and pathological conditions in southern sea otters. Environmental Science & Technology 40:4943-4948.

Kannan, K., E. Perrotta, N.J. Thomas, and K.M. Aldous. 2007. A comparative analysis of polybrominated diphenyl ethers and polychlorinated biphenyls in southern sea otters that died of infectious diseases and noninfectious causes. Archives of Environmental Contamination and Toxicology 53:293-302.

Kannan K., K.S. Guruge, N.J. Thomas, S. Tanabe, J.P. Giesy. 1998. Butyltin residues in southern sea otters (Enhydra lutris nereis) found dead along California coastal waters. Environmental Science and Technology 32:1169-1175.

Kooyman, G.L., and D.P. Costa. 1979. Effects of oiling on temperature regulation in sea otters. Yearly progress report, Outer Continental Shelf Energy Assessment Program.

Kreuder, C., M.A. Miller, D.A. Jessup, L.J. Lowenstein, M.D. Harris, J.A. Ames, T.E. Carpenter, P.A. Conrad, and J.A.K. Mazet. 2003. Patterns of mortality in southern sea otters (Enhydra lutris nereis) from 1998-2001. Journal of Wildlife Diseases 39(3):495-509.

Kreuder, C., M.A. Miller, L.J. Lowenstine, P.A. Conrad, T.E. Carpenter, D.A. Jessup, and J.A.K. Mazet. 2005. Evaluation of cardiac lesions and risk factors associated with myocarditis and dilated cardiomyopathy in southern sea otters (Enhydra lutris nereis). American Journal of Veterinary Research 66:289-299.

Laidre, K.L., R.J. Jameson, and D.P. DeMaster. 2001. An estimation of carrying capacity for sea otters along the California coast. Marine Mammal Science 17(2):294-309.

Larson, S., R. Jameson, J. Bodkin, M. Staedler, and P. Bentzen. 2002. Microsatellite DNA and mitochondrial DNA variation in remnant and translocated sea otter (Enhydra lutris) populations. J. Mammal. 83(3):893-906.

Mayer, K.A., M.D. Dailey, and M.A. Miller. 2003. Helminth parasites of the southern sea otter Enhydra lutris nereis in central California: abundance, distribution, and pathology. Diseases of Aquatic Organisms 53:77-88.

Nakata, H., K. Kannan, L. Jing, N. Thomas, S. Tanabe, and J.P. Giesy. 1998. Accumulation pattern of organochlorine pesticides and polychlorinated biphenyls in southern sea otters (Enhydra lutris nereis) found stranded along coastal California, USA. Environ. Poll. 103:45-53.

Ralls, K., T.C. Eagle, and D.B. Siniff. 1996. Movement and spatial use patterns of California sea otters. Canadian Journal of Zoology 74:1841-1849.

Riedman, M.L., and J.A. Estes. 1990. The sea otter (Enhydra lutris): behavior, ecology, and natural history. U.S. Fish and Wildlife Service, Biol. Rep. 90(14). 126 pp.

Riedman, M.L., J.A. Estes, M.M. Staedler, A.A. Giles, and D.R. Carlson. 1994. Breeding patterns and reproductive success of California sea otters. J. Wildl. Manage. 58:391-399.

Sanchez, M.S. 1992. Differentiation and variability of mitochondrial DNA in three sea otter, Enhydra lutris, populations. M.S. Thesis, University of California Santa Cruz.

Siniff, D.B., and K. Ralls. 1991. Reproduction, survival, and tag loss in California sea otters. Marine Mammal Science 7(3):211-229.

Siniff, D.B., T.D. Williams, A.M. Johnson, and D.L. Garshelis. 1982. Experiments on the response of sea otters, Enhydra lutris, to oil contamination. Biol. Conserv. 2: 261-272.

Taylor, B.L., M. Scott, J. Heyning, and J. Barlow. 2002. Suggested guidelines for recovery factors for endangered marine mammals. Unpublished report submitted to the Pacific Scientific Review Group. 7 pp.

Tinker, M.T., G. Bentall, and J.A. Estes. 2008. Food limitation leads to behavioral diversification and dietary specialization in sea otters. PNAS 105:560-565.

Tinker, M.T., J.A. Estes, K. Ralls, T.M. Williams, D. Jessup, and D.P. Costa. 2006. Population Dynamics and Biology of the California Sea Otter (Enhydra lutris nereis) at the Southern End of its Range. MMS OCS Study 2006-007. Coastal Research Center, Marine Science Institute, University of California, Santa Barbara, California. MMS Cooperative Agreement Number 14-35-0001-31063.

U.S. Fish and Wildlife Service. 2003. Final Revised Recovery Plan for the Southern Sea Otter (Enhydra lutris nereis). Portland, Oregon. xi + 165 pp.

Wendell, F.E., R.A. Hardy, and J.A. Ames. 1986. An assessment of the accidental take of sea otters, Enhydra lutris, in gill and trammel nets. California Department of Fish and Game, Mar. Res. Tech. Rep. 1991. Geographic variation in sea otters, Enhydra lutris. J. Mammal. 72(1):22-36.

Wilson, D.E., M.A. Bogan, R.L. Brownell, Jr., A.M. Burdin, and M.K. Maminov. 1991. Geographic variation in sea otters, Enhydra lutris. J. Mammal. 72(1):22-36.

Dated: June 3, 2008.

H. Dale Hall,

Director, Fish and Wildlife Service.