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Sea Otter SP-781 - History

Sea Otter SP-781 - History


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Sea Otter
(SP-781: t. 6; 1. 40'; b. 10'1"; dr. 3'6"; s. 10 k.; cpl. 6
a. 1 1-pdr., 1 mg.)

On 11 June 1917, soon after the United States entered World War I, Sea Otter, a wooden boat built during 1911 by Britt Brothers, Lynn Mass., was acquired by the Navy from Hugh L. Willoughby of Newport, R. I.; and placed in service the same day.

Sea Otter served as a supply vessel on the east coast of the United States until placed out of service at war's end. Struck from the Navy list on 7 November 1919 Sea Otter was sold on 16 January 1920 to Joseph Guild of Boston.


A Middle Pleistocene Sea Otter from Northern California and the Antiquity of Enhydra in the Pacific Basin

Extant sea otters (Enhydra lutris) are remarkably well understood in terms of behavior, ecology, and interactions with humans, but the evolutionary history of this charismatic marine mammal is limited owing to a fragmentary fossil record. Disagreements over the generic assignment of various fossil otter remains to members of the tribe Enhydrini, and limited geochronologic data for these records have impeded attempts to interpret the evolutionary biogeography of Enhydra. A well-preserved femur of Enhydra sp. from a middle Pleistocene horizon within the Merced Formation of northern California is the oldest record of Enhydra in the Pacific with robust geochronologic age control. Bracketing 87 Sr/ 86 Sr dates indicate an age of 620–670 ka. Reappraisal of the geochronologic age of various occurrences of Enhydrini indicate dispersal of Enhydra into the Pacific through the Bering Strait no earlier than the middle Pleistocene. Somewhat older early Pleistocene fossils of Enhydra from Alaska and England suggest an Arctic or North Atlantic origin of the Enhydra lineage.

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Sea Otter Coats

Sea otters are meticulously clean. After eating, they wash themselves in the ocean, cleaning their coat with their teeth and paws. They have good reason to take care of their coats—it helps them to remain waterproof and insulated against the cold. Sea otters have thick underfur that traps air to form an insulating layer against the chilly waters (they have no insulating fat). This coat is invaluable to otters, but it has worth to some humans as well.

Sea otters were hunted for their fur to the point of near extinction. Early in the 20th century only 1,000 to 2,000 animals remained. Today, sea otters are protected by law.


Habitat and Distribution

Unlike some marine mammals like whales that would die if they were on land for too long, sea otters can go up onto land to rest, groom, or nurse. However, they do spend most if not all of their lives in the water—Sea otters even give birth in the water.

Although there is just one species of sea otter, there are three subspecies:

  • The Russian northern sea otter (Enhyrda lutris lutris), which lives in the Kuril Islands, Kamchatka Peninsula, and Commander Islands off Russia,
  • The northern sea otter (Enhyrda lutris kenyoni), which lives from the Aleutian Islands off Alaska, down to Washington state, and
  • The southern sea otter (Enhyrda lutris nereis), which lives in southern California.

Sea otters eat fish and marine invertebrates like crabs, urchins, sea stars, and abalone, as well as squid and octopuses. Some of these animals have hard shells, which protect them from predators. But that isn't an issue for the talented sea otter, which cracks open the shells by banging them with rocks.

To hunt prey, sea otters have been known to dive as deep as 320 feet however, males mostly forage at depths of around 260 feet and females about 180 feet.

Sea otters have a baggy patch of skin under their forelimbs which is used for storage. They can keep extra food in this spot, and also store a favorite rock for cracking the shell of their prey.


Abstract

Halarachne sp. nasal mites infest harbor seals (Phoca vitulina) and southern sea otters (Enhydra lutris nereis) in California, but little is known about the pathophysiology of these infestations, or risk factors for exposure. To investigate these questions, a retrospective case-control study was performed using necropsy data from 70 mite-infested sea otters, and 144 non-infested controls. Case records for sea otters examined by pathologists from February 1999 through May 2015 were examined to assess risk factors for infestation, and lesions associated with nasopulmonary acariasis. Animals with a history of captive care within 10 days of death or carcass recovery were 3.2 times more likely to be infested with nasopulmonary mites than those with no history of recent rehabilitation. Sea otters stranding within 1 km of Elkhorn Slough in Monterey Bay were 4.9 times more likely to be infested with nasal mites than other areas this site is characterized by high sea otter contact with sympatric harbor seals (a common host for Halarachne sp.), and a comparatively large population of rehabilitated and released sea otters. Aged adult otters were 9.4 times more likely to be infested than younger animals, and sea otters with nasopulmonary acariasis were 14.2 times more likely to have upper respiratory inflammation than un-infested animals. Additional findings in otters with nasopulmonary acariasis included lower respiratory tract bacterial infections, presence of medium-sized and/or fresh nose wounds at necropsy (indicators of recent face-to-face interaction between otters during copulation or fighting), and turbinate bone erosion. Our findings, although preliminary, suggest that captive rehabilitation and close contact with harbor seals could facilitate nasopulmonary mite transmission to sea otters. We also identified a high-risk zone for nasopulmonary acariasis in sea otters. We also provide preliminary data to suggest that nasopulmonary mite infestations can cause significant respiratory pathology in sea otters.


Description and Range

The sea otter is the smallest of the marine mammals and the largest member of the weasel family (Mustelidae).

Ecology and life history

Sea otters are commonly found in rocky marine habitats and kelp beds within 1.2 miles of the coast. Females tend to use habitats closer to the shore than males.

In rough weather, otters take refuge among kelp or in coves and inlets.

It is a carnivore and feeds on urchins, crabs, clams, mussels, snails, and chitons. It uses rocks to break the shells and exoskeletons of its prey and expose the edible interior of these species. Predation by sea otters on urchins has been found to maintain stability within marine invertebrate communities the species is considered a keystone species because of this effect.

The dense fur of the sea otter made its pelt extremely valuable to fur traders, which led to overexploitation of the species in the 1700s and 1800s.

Otter mortality can result from oil spills and incidental capture in nets and traps set for fish, shellfish, and crabs.

The sea otter is found only in the northern Pacific Ocean. In Washington, it is limited in distribution to the marine waters from south of Destruction Island north to Cape Flattery, and east to Pillar Point in the Strait of Juan de Fuca. The Washington population had increased steadily from 59 individuals reintroduced in 1969 to 1970 to almost 1,600 otters in 2014.

For maps of distribution and conservation status of sea otter, check out NatureServe Explorer and the International Union for the Conservation of Nature Red List.


Population

Sea otter numbers have declined in southwestern Alaska over the past 20 years. Once containing more than half of the world’s sea otters, this population segment, which ranges from Kodiak Island through the western Aleutian Islands, has undergone an overall population decline of at least 55–67 percent since the mid-1980s. In 2005, the U.S. Fish and Wildlife Service listed this distinct population segment as Threatened under the Endangered Species Act. See the Sea Otters and the Endangered Species Act page for more details.


  1. ^In the United States, white abalone (Haliotis sorenseni) were listed as endangered under the Endangered Species Act in 2001, and black abalone (Haliotis cracherodii) were listed as endangered in 2009. In Canada, northern abalone (Haliotis kamtschatkana) were listed under the Species at Risk Act in 2003.

Anthony, R. G., Estes, J. A., Ricca, M. A., Miles, A. K., and Forsman, E. D. (2008). Bald eagles and sea otters in the Aleutian Archipelago: indirect effects of trophic cascades. Ecology 89, 2725�. doi: 10.1890/07-1818.1

Arkema, K. K., Guannel, G., Verutes, G., Wood, S. A., Guerry, A., Ruckelshaus, M., et al. (2013). Coastal habitats shield people and property from sea-level rise and storms. Nat. Clim. Change 3, 913�. doi: 10.1038/nclimate1944

Atwood, T. B., Connolly, R. M., Ritchie, E. G., Lovelock, C. E., Heithaus, M. R., Hays, G. C., et al. (2015). Predators help protect carbon stocks in blue carbon ecosystems. Nat. Clim. Change 5, 1038�. doi: 10.1038/nclimate2763

Atwood, T. B., and Hammill, E. (2018). The importance of marine predators in the provisioning of ecosystem services by coastal plant communities. Front. Plant Sci. 9:1289. doi: 10.3389/fpls.2018.01289

Ballachey, B. E., Bodkin, J. L., and DeGange, A. R. (1994). 𠇊n overview of sea otter studies,” in Marine Mammals and the Exxon Valdez, ed. T. R. Loughlin (San Diego, CA: Academic Press), 47�. doi: 10.1016/B978-0-12-456160-1.50010-2

Barabash-Nikiforov, I. I. (1947). “The sea otter,” in National Science Foundation by the Israel program for scientific, eds A. Birron and Z. S. Cole (Jerusalem: Soviet Ministrov RSFSR), 227.

Bednykh, A. M., Burkanov, V. N., Kornev, S. I., and Krivolapov, I. I. (1986). 𠇎xtent and causes of sea otter mortality in kamchatka,” in Proceedings of the 9th All-Union Conference on Research, Conservation and Utilization of Marine Mammals, Archangelsk, 22�.

Bigg, M. A., and MacAskie, I. B. (1978). Sea otters reestablished in British Columbia. J. Mammal. 59, 874�. doi: 10.2307/1380163

Bodkin, J. L. (2015). “Historic and contemporary status of sea otters in the North Pacific,” in Sea Otter Conservation, eds S. E. Larson, J. L. Bodkin, and G. R. VanBlaricom (London: Elsevier), 43�.

Bodkin, J. L., Ballachey, B. E., Cronin, M. A., and Scribner, K. T. (1999). Population demographics and genetic diversity in remnant and translocated populations of sea otters. Conserv. Biol. 13, 1378�. doi: 10.1046/j.1523-1739.1999.98124.x

Bodkin, J. L., Coletti, H. A., Ballachey, B. E., Monson, D. H., Esler, D., and Dean, T. A. (2018). Variation in abundance of Pacific Blue Mussel (Mytilus trossulus) in the Northern Gulf of Alaska, 2006�. Deep-Sea Res. Part 2 Top Stud. Oceanogr. 147, 87�. doi: 10.1016/j.dsr2.2017.04.008

Bodkin, J. L., Dean, T. A., Coletti, H. A., and Ballachey, B. E. (2016). Mussel Bed Sampling: Standard Operating Procedure, v. 1.2, Southwest Alaska Network. Natural Resource Report NPS/SWAN/NRR�/1175. Fort Collins, CO: National Park Service.

Bodkin, J. L., Monson, D. H., and Esslinger, G. G. (2007). Activity budgets derived from time-depth recorders in a diving mammal. J. Wildl. Manage. 71, 2034�. doi: 10.1038/srep33912

Carswell, L. P., Speckman, S. G., and Gill, V. A. (2015). “Shellfish fishery conflicts and perceptions of sea otters in California and Alaska,” in Sea Otter Conservation, eds S. E. Larson, J. L. Bodkin, and G. R. VanBlaricom (London: Elsevier), 335�.

Chadès, I., Curtis, J., and Martin, T. (2012). Setting realistic recovery targets for interacting endangered species. Conserv. Biol. 26, 1016�. doi: 10.1111/j.1523-1739.2012.01951.x

Coletti, H. A., Bodkin, J. L., Monson, D. H., Ballachey, B. E., and Dean, T. A. (2016). Detecting and inferring cause of change in an Alaska nearshore marine ecosystem. Ecosphere 7:e01489. doi: 10.1002/ecs2.1489

Conrad, P. A., Kreuder, C., Mazet, J., Dabritz, H., Grigg, M., James, E., et al. (2005a). Sea otters serve as sentinels for protozoal pathogens transmitted from the terrestrial hosts to marine mammals. Am. J. Trop. Med. Hyg. 73, 8𠄸.

Conrad, P. A., Miller, M. A., Kreuder, C., James, E. R., Mazet, J., Dabritz, H., et al. (2005b). Transmission of toxoplasma: clues from the study of sea otters as sentinels of Toxoplasma gondii flow into the marine environment. Int. J. Parasitol. 35, 1155�.

Cortez, M., Wolt, R., and Davis, R. W. (2016). Development of an altricial mammal at sea I: activity budgets of female sea otters and their pups in Simpson Bay. Alaska. J. Exp. Mar. Biol. Ecol. 481, 71�. doi: 10.1016/j.jembe.2015.05.020

Costa, D. P., and Kooyman, G. L. (1984). Contribution of specific dynamic action to heat balance and thermoregulation in the sea otter Enhydra lutris. Physiol. Zool. 57, 199�. doi: 10.1086/physzool.57.2.30163705

Counihan, K. L., Gill, V. A., Miller, M. A., Burek-Huntington, K. A., LeFebvre, R. B., and Byme, B. A. (2015). Pathogenesis of Streptococcus infantarius subspecies coli isolated from sea otters with infective endocarditis. Comp. Immunol. Microbiol. Infect. Dis. 40, 7�. doi: 10.1016/j.cimid.2015.03.002

Dean, T. A., and Bodkin, J. L. (2011). SOP for Sampling of Intertidal Invertebrates and Algae on Sheltered Rocky Shores - Version 4.6: Southwest Alaska Inventory and Monitoring Network. Natural Resource Report. NPS/SWAN/NRR�/397. Fort Collins, CO: National Park Service.

Dean, T. A., Bodkin, J. L., and Coletti, H. A. (2014). Protocol Narrative for Nearshore Marine Ecosystem Monitoring in the Gulf of Alaska: Version 1.1. Natural Resource Report NPS/SWAN/NRR – 2014/756. Fort Collins, CO: National Park Service.

Doroff, A. M., Estes, J. A., Tinker, M. T., Burn, D. M., and Evans, T. J. (2003). Sea otter population declines in the Aleutian archipelago. J. Mamm. 84, 55�. doi: 10.1016/j.chemosphere.2012.03.096

Esslinger, G. G., and Bodkin, J. L. (2009). Status and Trends of Sea Otter Populations in Southeast Alaska, 1969�. U.S. Geological Survey Scientific Investigations Report 2009�. Reston, VA.

Estes, J. A. (1990). Growth and equilibrium in sea otter populations. J. Anim. Ecol. 59, 385�. doi: 10.2307/4870

Estes, J. A., and Duggins, D.O. (1995). Sea otters and kelp forests in Alaska – generality and variation in a community ecological paradigm. Ecol. Monogr. 65, 75�. doi: 10.2307/2937159

Estes, J. A. (2015). “Natural history, ecology, and the conservation and management of sea otters,” in Sea Otter Conservation, eds S. E. Larson, J. L. Bodkin, and G. R. VanBlaricom (London: Elsevier), 19�.

Estes, J. A., Hatfield, B. B., Ralls, K., and Ames, J. (2003). Causes of mortality in California sea otters during periods of population growth and decline. Mar. Mamm. Sci. 19, 198�. doi: 10.1111/j.1748-7692.2003.tb01102.x

Estes, J. A., and Jameson, R. J. (1988). A double-survey estimate for sighting probability of sea otters in California. J. Wildl. Manage. 52, 70�. doi: 10.2307/3801061

Estes, J. A., and Palmisano, J. F. (1974). Sea otters: their role in structuring nearshore communities. Science 185, 1058�. doi: 10.1126/science.185.4156.1058

Estes, J. A., Tinker, M. T., Doroff, A. M., and Burn, D. M. (2005). Continuing sea otter population declines in the Aleutian archipelago. Mar. Mamm. Sci. 21, 169�. doi: 10.1111/j.1748-7692.2005.tb01218.x

Estes, J. A., Tinker, M. T., Williams, T. M., and Doak, D. F. (1998). Killer whale predation on sea otters linking oceanic and nearshore ecosystems. Science 282, 473�. doi: 10.1126/science.282.5388.473

Estes, J. A., Underwood, K. E., and Karmann, M. J. (1986). Activity-time budgets of sea otters in California. J. Wildl. Manage. 50, 626�. doi: 10.2307/3800973

Estes, J. A., and VanBlaricom, G. R. (1985). “Sea-otters and shellfisheries,” in Marine Mammals and Fisheries, eds J. R. Beddington, R. J. H. Beverton, and D. M. Lavigne (London: George Allen & Unwin), 187�.

Federal Register 77. (2012). Interior Department Fish and Wildlife Service, Vol. 77. College Park, MD: National Archives and Records Administration, 75266.

Forney, K. A., Benson, S. R., and Cameron, G. A. (2001). �ntral California gill net effort and bycatch of sensitive species, 1990-1998,” in Seabird Bycatch: Trends, Roadblocks, and Solutions, eds E. F. Melvin and J. K. Parrish (Fairbanks, AK: University of Alaska Sea Grant), 141�.

Gagne, R. B., Tinker, M. T., Gustafson, K. D., Ralls, K., Larson, S., Tarjan, L. M., et al. (2018). Measures of effective population size in sea otters reveal special considerations for wide-ranging species. Evol. Appl. 11, 1779�. doi: 10.1111/eva.12642

Garshelis, D. L., Johnson, A. M., and Garshelis, J. A. (1984). Social organization of sea otters in prince william sound, Alaska. Can. J. Zool. 62, 2648�. doi: 10.1139/z84-385

Garshelis, D. L., and Siniff, D. B. (1983). Evaluation of radio transmitter attachments for sea otters. Wildl. Soc. Bull. 11, 378�.

Gelatt, T. S. (1996). Activity Patterns and Time Budgets of Sea Otters at Amchitka Island, Alaska. M.S. thesis, University of Minnesota, St. Paul, MN.

Gorbics, C. S., and Bodkin, J. L. (2001). Stock structure of sea otters (Enhydra lutris kenyoni) in Alaska. Mar. Mamm. Sci. 17, 632�. doi: 10.1111/j.1748-7692.2001.tb01009.x

Groesbeck, A. S., Rowell, K., Lepofsky, D., and Salomon, A. K. (2014). Ancient clam gardens increased shellfish production: adaptive strategies from the past can inform food security today. PLoS One 9:e91235. doi: 10.1371/journal.pone.0091235

Hatfield, B. B., Ames, J. A., Estes, J. A., Tinker, M. T., Johnson, A. B., Staedler, M. M., et al. (2011). Sea otter mortality in fish and shellfish traps: estimating potential impacts and exploring possible solutions. Endanger. Species Res. 13, 219�. doi: 10.3354/esr00327

Hattori, K., Kawabe, I., Mizuno, A. W., and Ohtaishi, N. (2005). History and status of sea otters, Enhydra lutris along the coast of Hokkaido, Japan. Mamm. Study 30, 41�. doi: 10.3106/1348-6160(2005)30[41:HASOSO]2.0.CO2

Heithaus, M. R., and Dill, L. M. (2006). Does tiger shark predation risk influence foraging habitat use by bottlenose dolphins at multiple spatial scales? Oikos 114, 257�. doi: 10.1111/j.2006.0030-1299.14443.x

Heithaus, M. R., Frid, A., Wirsing, A. J., and Worm, B. (2008). Predicting ecological consequences of marine top predator declines. Trends Ecol. Evol. 23, 202�. doi: 10.1016/j.tree.2008.01.003

Herrick, Jr, and Hanan, D. (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. Silver Spring, MD: National Oceanic and Atmospheric Administration.

Hoyt, Z. N. (2015). Resource Competition, Space Use and Forage Ecology of Sea Otters, Enhydra lutris, in Southern Southeast Alaska. Ph.D. thesis, University of Alaska, Fairbanks.

Hughes, B. B., Eby, R., Van Dyke, E., Tinker, M. T., Marks, C. I., Johnson, K. S., et al. (2013). Recovery of a top predator mediates negative eutrophic effects on seagrass. Proc. Nat. Acad. Sci. U.S.A. 110, 15313�. doi: 10.1073/pnas.1302805110

Jameson, R. J., Kenyon, K. W., Johnson, A. M., and Wight, H. M. (1982). History and status of translocated sea otter populations in North America. Wildl. Soc. Bull. 10, 100�.

Johnson, C. K., Tinker, M. T., Estes, J. A., Conrad, P. A., Staedler, M., Miller, M. A., et al. (2009). Prey choice and habitat use drive sea otter pathogen exposure in a resource-limited coastal system. Proc. Nat. Acad. Sci. U.S.A. 106, 2242�. doi: 10.1073/pnas.0806449106

Kenyon, K. W. (1969). The Sea Otter in the Eastern Pacific Ocean North American Fauna. Washington, DC: U.S. Fish and Wildlife Service.

Kreuder, C., Miller, M. A., Jessup, D. A., Lowenstine, L. J., Harris, M. D., Ames, J. A., et al. (2003). Patterns of mortality in southern sea otters (Anhydrates lutris nereis) from 1998�. J. Wildl. Dis. 39, 495�. doi: 10.7589/0090-3558-39.3.495

Krkosek, M., Lauzon-Guay, J. S., and Lewis, M. A. (2007). Relating dispersal and range expansion of California sea otters. Theor. Popul. Biol. 71, 401�. doi: 10.1016/j.tpb.2007.01.008

Kvitek, R. G., Bowlby, C. E., and Staedler, M. (1993). Diet and foraging behavior of sea otters in southeast Alaska. Mar. Mamm. Sci. 9, 168�. doi: 10.1111/j.1748-7692.1993.tb00441.x

Kvitek, R. G., and Oliver, J. S. (1992). Influence of sea otters on soft-bottom prey communities in southeast Alaska. Mar. Ecol. Prog. Ser. 82, 103�. doi: 10.3354/meps082103

Kvitek, R. G., Oliver, J. S., DeGange, A. R., and Anderson, B. S. (1992). Changes in Alaskan soft-bottom prey communities along a gradient in sea otter predation. Ecology 73, 413�. doi: 10.2307/1940749

Laidre, K. L., Estes, J. A., Tinker, M. T., Bodkin, J., Monson, D., and Schneider, K. (2006). Patterns of growth and body condition in sea otters from the Aleutian archipelago before and after the recent population decline. J. Anim. Ecol. 75, 978�. doi: 10.1111/j.1365-2656.2006.01117.x

Lapiedra, O., Schoener, T. W., Leal, M., Losos, J. B., and Kolbe, J. J. (2018). Predator-driven natural selection on risk-taking behavior in anole lizards. Science 360, 1017�. doi: 10.1126/science.aap9289

Larson, S., Jameson, R., Bodkin, J., Staedler, M., and Bentzen, P. (2002a). Microsatellite DNA and MtDNA variation in remnant and translocated sea otter (Enhydra lutris) populations. J. Mamm. 83, 893�. doi: 10.1644/1545-1542(2002)083�:MDAMDVϢ.0.CO2

Larson, S., Jameson, R., Etnier, M., Fleming, M., and Bentzen, P. (2002b). Loss of genetic diversity in sea otters (Enhydra lutris) associated with the fur trade of the 18th and 19th centuries. Mol. Ecol. 11, 1899�.

Larson, S., Jameson, R., Etnier, M., Jones, T., and Hall, R. (2012). Genetic diversity and population parameters of sea otters, Enhydra lutris, before fur trade extirpation from 1741�. PLoS One 7:e32205. doi: 10.1371/journal.pone.0032205

Larson, S. D., Hoyt, Z. N., Eckert, G. L., and Gill, V. A. (2013). Impacts of sea otter (Enhydra lutris) predation on commercially important sea cucumbers (Parastichopus californicus) in southeast Alaska. Can. J. Fish. Aquat. Sci. 70, 1498�. doi: 10.1139/cjfas-2013-0025

Larson, S. E., and Bodkin, J. L. (2015). “The conservation of sea otters: a prelude,” in Sea Otter Conservation, eds S. E. Larson, J. L. Bodkin, and G. R. VanBlaricom (London: Elsevier Academic Press), 1�. doi: 10.1016/B978-0-12-801402-8.00001-9

Larson, S. E., Ralls, K., and Ernest, H. (2015). “Sea otter conservation genetics,” in Sea Otter Conservation, eds S. E. Larson, J. L. Bodkin, and G. R. VanBlaricom (London: Elsevier Academic Press), 97�. doi: 10.1016/B978-0-12-801402-8.00005-6

Lee, J., Watson, C., Trebilco, R., and Salomon, A. K. (2016). Indirect effects and prey behavior mediate interactions between an endangered prey and recovering predator. Ecosphere 7:e01604. doi: 10.1002/ecs2.1604

Lensink, C. J. (1960). Status and distribution of sea otters in Alaska. J. Mamm. 41, 172�. doi: 10.2307/1376352

Lensink, C. J. (1962). The History and Status of Sea Otters in Alaska. Ph.D. thesis. Purdue University, West Lafayette IN.

Loomis, J. (2006). Estimating recreation and existence values of sea otter expansion in California using benefit transfer. Coast. Manag. 34, 387�. doi: 10.1080/08920750600860282

Lubina, J. A., and Levin, S. A. (1988). The spread of a reinvading species – range expansion in the California sea otter. Am. Nat. 131, 526�. doi: 10.1086/284804

Markel, R. W. (2011). Rockfish Recruitment and Trophic Dynamics on the West Coast of Vancouver Island: Fishing, Ocean Climate, and Sea Otters. Ph.D. thesis, University of British Columbia, Vancouver.

Markel, R. W., and Shurin, J. B. (2015). Indirect effects of sea otters on rockfish (Sebastes spp.) in giant kelp forests. Ecology 96, 2877�. doi: 10.1890/14-0492.1

Mazzillo, F. F. M., Shapiro, K., and Silver, M. W. (2013). A new pathogen transmission mechanism in the ocean: the case of sea otter exposure to the land-parasite Toxoplasma gondii. PLoS One 8:e82477. doi: 10.1371/journal.pone.0082477

Menge, B. A., Chan, F., Nielsen, K. J., Lorenzo, E. D., and Lubchenco, J. (2009). Climatic variation alters supply-side ecology: impact of climate patterns on phytoplankton and mussel recruitment. Ecol. Monogr. 79, 379�. doi: 10.1890/08-2086.1

Menge, B. A., Daley, B. A., Wheeler, P. A., Dahlhoff, E., Sanford, E., and Strub, P. T. (1997). Benthic–pelagic links and rocky intertidal communities: bottom-up effects on top-down control? Proc. Natl. Acad. Sci. U.S.A. 94, 14530�. doi: 10.1073/pnas.94.26.14530

Miller, M. A., Gardner, I. A., Kreuder, C., Paradies, D. M., Worcester, K. R., Jessup, D. A., et al. (2002). Coastal freshwater runoff is a risk factor for Toxoplasma gondii infection of southern sea otters (Enhydra lutris nereis). Int. J. Parasitol. 32, 997�. doi: 10.1016/S0020-7519(02)00069-3

Miller, M. A., Grigg, M. E., Kreuder, C., James, E. R., Melli, A. C., Crosbie, P. R., et al. (2004). An unusual genotype of Toxoplasma gondii is common in California sea otters (Enhydra lutris nereis) and is a cause of mortality. Int J. Parasitol. 34, 275�. doi: 10.1016/j.ijpara.2003.12.008

Monson, D., Estes, J. A., Siniff, D. B., and Bodkin, J. L. (2000). Life history plasticity and population regulation in sea otters. Oikos 90, 457�. doi: 10.1034/j.1600-0706.2000.900304.x

Monson, D. H. (2009). Sea Otters (Enhydra lutris) and Steller Sea Lions (Eumetopias jubatus) in the North Pacific: Evaluating Mortality Patterns and Assessing Population Status at Multiple Time Scales. Ph.D. thesis, University of California, Santa Cruz, CA.

Monson, D. H., and Bowen, L. (2015). 𠇎valuating the status of individuals and populations: advantages of multiple approaches and time scales,” in Sea Otter Conservation, eds S. E. Larson, J. L. Bodkin, and G. R. VanBlaricom (London: Elsevier Academic Press), 119�. doi: 10.1016/B978-0-12-801402-8.00006-8

Monson, D. H., and DeGange, A. R. (1995). Reproduction, preweaning survival, and survival of adult sea otters at Kodiak Island, Alaska. Can. J. Zool. 73, 1161�. doi: 10.1139/z95-138

Nichol, L. M. (2015). 𠇌onservation in Practice,” in Sea Otter Conservation, eds S. E. Larson, J. L. Bodkin, and G. R. VanBlaricom (London: Elsevier Academic Press), 369�. doi: 10.1016/B978-0-12-801402-8.00013-5

Pennock, D. S., and Dimmick, W. W. (1997). Critique of the evolutionarily significant unit as a definition for 𠇝istinct population segments” under the US endangered Species act. Conserv. Biol. 11, 611�. doi: 10.1046/j.1523-1739.1997.96109.x

Raimondi, P., Jurgens, L. J., and Tinker, M. T. (2015). Evaluating potential conservation conflicts between two listed species: sea otters and black abalone. Ecology 96, 3102�. doi: 10.1890/15-0158.1

Rathbun, G. B., Hatfield, B. B., and Murphey, T. G. (2000). Status of translocated sea otters at San Nicolas Island, California. Southwest. Nat. 45, 322�. doi: 10.2307/3672835

Reidy, R. D., and Cox, S. P. (2013). Geoduck clam (Panopea abrupta) demographics and mortality rates in the presence of sea otters (Enhydra lutris) and commercial harvesting. Open Fish Sci. J. 6, 28�. doi: 10.2174/1874401X01306010028

Richardson, L., and Loomis, J. (2009). The total economic value of threatened, endangered and rare species: an updated meta-analysis. Ecol. Econ. 68, 1535�. doi: 10.1016/j.ecolecon.2008.10.016

Riedman, M. L., and Estes, J. A. (1990). The Sea Otter (Enhydra lutris): Behavior, Ecology and Natural History. Washington, DC: U.S. Fish and Wildlife Service.

Salomon, A. K., Kii’iljuus Barb, J. W., White, X. E., Tanape, N., and Happynook, T. M. (2015). 𠇏irst nations perspectives on sea otter conservation in british columbia and alaska: insights into coupled human-ocean systems,” in Sea Otter Conservation, eds S. E. Larson, J. L. Bodkin, and G. R. VanBlaricom (London: Elsevier Academic Press), 301�. doi: 10.1016/B978-0-12-801402-8.00011-1

Sato, C. L. (2018). Draft Periodic Status Review for the Sea Otter in Washington. Olympia, WA: Washington Department of Fish and Wildlife.

Schmitz, O. J., Raymond, P. A., Estes, J. A., Kurz, W. A., Holtgrieve, G. W., Ritchie, M. E., et al. (2014). Animating the carbon cycle. Ecosystems 17, 344�. doi: 10.1007/s10021-013-9715-7

Scribner, K. T., Bodkin, J., Ballachey, B., Fain, S. R., Cronin, M. A., and Sanchez, M. (1997). “Population genetic studies of the sea otter (Enhydra lutris): a review and interpretation of available data,” in Molecular Genetics of Marine Mammals, Vol. 3, eds A. E. Dizon, S. J. Chivers, and W. F. Perrin (Lawrence, KS: Special publication of the Society of Marine Mammalogy), 197�.

Sherrod, S. K., Estes, J. A., and White, C. M. (1975). Depredation of sea otter pups by bald eagles at Amchitka Island, Alaska. J. Mammal. 56, 701�. doi: 10.2307/1379491

Simenstad, C. A., Estes, J. A., and Kenyon, K. W. (1978). Aleuts, sea otters, and alternate stable-state communities. Science 200, 403�. doi: 10.1126/science.200.4340.403

Singh, G. G., Markel, R. W., Martone, R. G., Salomon, A. K., Harley, C. D. G., and Chan, K. M. A. (2013). Sea otters may homogenize mussel-beds and reduce habitat provisioning in a rocky intertidal ecosystem. PLoS One 8:e65435. doi: 10.1371/journal.pone.0065435

Springer, A. M., Estes, J. A., van Vliet, G. B., Williams, T. M., Doak, D. F., Danner, E. M., et al. (2003). Sequential megafaunal collapse in the North Pacific Ocean: an ongoing legacy of industrial whaling? Proc. Nat. Acad. Sci. U.S.A. 100, 12223�. doi: 10.1073/pnas.1635156100

Stewart, N. L., Konar, B., and Tinker, M. T. (2015). Testing the nutritional-limitation, predator-avoidance, and storm-avoidance hypotheses for restricted sea otter habitat use in the Aleutian Islands, Alaska. Oecologia 177, 645�. doi: 10.1007/s00442-014-3149-6

Szpak, P., Orchard, T. J., McKechnie, I., and Grཬke, D. R. (2012). Historical ecology of late Holocene sea otters (Enhydra lutris) from northern British Columbia: isotopic and zooarchaeological perspectives. J. Arch. Sci. 39, 1553�. doi: 10.1016/j.jas.2011.12.006

Tallis, H. (2009). Kelp and rivers subsidize rocky intertidal communities in the Pacific Northwest (USA). Mar. Ecol. Prog. Ser. 389, 85�. doi: 10.3354/meps08138

Tarjan, L. M., and Tinker, M. T. (2016). Permissible home range estimation (PHRE) in restricted habitats: a new algorithm and an evaluation for sea otters. PLoS One 11:e0150547. doi: 10.1371/journal.pone.0150547

Tinker, M. T. (2015). “The use of quantitative models in sea otter conservation,” in Sea Otter Conservation, eds S. E. Larson, J. L. Bodkin, and G. R. VanBlaricom (London: Elsevier Academic Press), 257�.

Tinker, M. T., Doak, D. F., Estes, J. A., Hatfield, B. B., Staedler, M. M., and Bodkin, J. L. (2006). Incorporating diverse data and realistic complexity into demographic estimation procedures for sea otters. Ecol. Appl. 16, 2293�. doi: 10.1890/1051-0761(2006)016[2293:IDDARC]2.0.CO2

Tinker, M. T., and Hatfield, B. B. (2017). California Sea Otter (Enhydra lutris nereis) Census Results Spring 2017: U.S. Geological Survey Data Series 1067. doi: 10.3133/ds1067

Tinker, M. T., Hatfield, B. B., Harris, M. D., and Ames, J. A. (2016). Dramatic increase in sea otter mortality from white sharks in California. Mar. Mamm. Sci. 32, 309�. doi: 10.1111/mms.12261

Traiger, S. B., Konar, B., Doroff, A., and McCaslin, L. (2016). Sea otters versus sea stars as major clam predators: evidence from foraging pits and shell litter. Mar. Ecol. Prog. Ser. 560, 73�. doi: 10.3354/meps11871

U.S. Fish and Wildlife Service (2013). Southwest Alaska Distinct Population Segment of the Northern Sea Otter (Enhydra lutris kenyoni) - Recovery Plan. Alaska: U.S. Fish and Wildlife Service.

Van Wormer, E., Miller, M. A., Conrad, P. A., Grigg, M. E., Rejmanek, D., and Carpenter, T. E. (2014). Using molecular epidemiology to track Toxoplasma gondii from terrestrial carnivores to marine hosts: implications for public health and conservation. PLoS Negl. Trop. Dis. 8:e2852. doi: 10.1371/journal.pntd.0002852

Watson, J., and Estes, J. A. (2011). Stability, resilience, and phase shifts in kelp forest communities along the west coast of Vancouver Island. Can. Ecol. Monogr. 81, 215�. doi: 10.1890/10-0262.1

Watson, J. C., and Smith, T. G. (1996). “The effect of sea otters on shellfisheries in British Columbia,” in Invertebrate Working Papers, eds C. M. Hand and B. J. Waddell (Ottawa: Fisheries and Oceans Canada), 262�.

Weitzman, B. P. (2013). Effects of Sea Otter Colonization on Soft-Sediment Intertidal Prey Assemblages in Glacier Bay, Alaska. Ph.D. thesis, University of California, Santa Cruz.

Weitzman, B. P., Bodkin, J. L., Kloecker, K. A., and Coletti, H. A. (2017). SOP for Monitoring Intertidal Bivalves on Mixed-Sediment Beaches - Version 2.0: Southwest Alaska Inventory and Monitoring Network. Natural Resource Report NPS/SWAN/NRR�/1443. Fort Collins, CO: National Park Service.

Wendell, F. (1994). Relationship between sea otter range expansion and red abalone abundance and size distribution in central California. Calif. Fish Game 80, 45�.

Wendell, F. E., Hardy, R. A., and Ames, J. A. (1986a). Assessment of the Incidental Take of Sea Otters, Enhydra lutris, in Gill and Trammel Nets. Technical Report No. 54. Sacramento CA: Marine Resources Branch.

Wendell, F. E., Hardy, R. A., Ames, J. A., and Burge, R. T. (1986b). Temporal and spatial patterns in sea otter (Enhydra lutris) range expansion and in the loss of the Pismo clam fisheries. Calif. Fish Game 72, 197�.

Willems, E. P., and Hill, R. A. (2009). Predator-specific landscapes of fear and resource distribution: effects on spatial range use. Ecology 90, 546�. doi: 10.1890/08-0765.1

Williams, P. J., Hooten, M. B., Womble, J. N., Esslinger, G. G., and Bower, M. R. (2018). Monitoring dynamic spatio-temporal ecological processes optimally. Ecology 99, 524�. doi: 10.1002/ecy.2120

Williams, T. M., Estes, J. A., Doak, D. F., and Springer, A. M. (2004). Killer appetites: Assessing the role of predators in ecological communities. Ecology 85, 3373�. doi: 10.1890/03-0696

Wilmers, C. C., Estes, J. A., Edwards, M., Laidre, K. L., and Konar, B. (2012). Do trophic cascades affect the storage and flux of atmospheric carbon? An analysis of sea otters and kelp forests. Front. Ecol. Environ. 10, 409�. doi: 10.2307/41811831

Wilson, D. E., Bogan, M. A., Brownell, R. L. Jr., Burdin, A. M., and Maminov, M. K. (1991). Geographic variation in sea otters, Enhydra lutris. J. Mamm. 72, 22�. doi: 10.2307/1381977

Wirsing, A. J., Heithaus, M. R., Frid, A., and Dill, L. M. (2008). Seascapes of fear: evaluating sublethal predator effects experienced and generated by marine mammals. Mar. Mamm. Sci. 24, 1�. doi: 10.1111/j.1748-7692.2007.00167.x

Wolt, R. C., Gelwick, F. P., Weltz, F., and Davis, R. W. (2012). Foraging behavior and prey of sea otters in a soft- and mixed-sediment benthos in Alaska. Mamm. Biol. 77, 271�. doi: 10.1016/j.mambio.2012.03.002

Yeates, L. C., Williams, T. M., and Fink, T. L. (2007). Diving and foraging energetics of the smallest marine mammal, the sea otter (Enhydra lutris). J. Exp. Biol. 210, 1960�. doi: 10.1242/jeb.02767

Keywords : sea otter, population, density, littoral, monitoring, translocation, fisheries, predation

Citation: Davis RW, Bodkin JL, Coletti HA, Monson DH, Larson SE, Carswell LP and Nichol LM (2019) Future Directions in Sea Otter Research and Management. Front. Mar. Sci. 5:510. doi: 10.3389/fmars.2018.00510

Received: 02 July 2018 Accepted: 21 December 2018
Published: 21 January 2019.

Rob Harcourt, Macquarie University, Australia

L. Max Tarjan, San Francisco Bay Bird Observatory, United States
Clive Reginald McMahon, Sydney Institute of Marine Science, Australia
Rebecca Ruth McIntosh, Phillip Island Nature Parks, Australia

Copyright © 2019 Davis, Bodkin, Coletti, Monson, Larson, Carswell and Nichol. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.


Sea Otter Conservation

California’s southern sea otter has been listed as a threatened species under the Endangered Species Act since 1977. 41 years later and counting, their conservation status remains unchanged and their future uncertain. Sea otter population growth has stalled in recent years and many hurdles for full population recovery remain. There are only about 3,000 southern sea otters left in the wild today.

Why Are Sea Otters Important?

Sea otters are an iconic species, representing the beauty and diversity of marine life found along California’s coastline. They’re also considered a keystone species because of their critical importance to the health and stability of the nearshore marine ecosystem. They eat sea urchins and other invertebrates that graze on giant kelp. Without sea otters, these grazing animals can destroy kelp forests and consequently the wide diversity of animals that depend upon kelp habitat for survival. Additionally, kelp forests protect coastlines from storm surge and absorb vast amounts of harmful carbon dioxide from the atmosphere. Sea otters are also considered a sentinel species because their health reflects that of California’s coastal waters.

Why Aren’t They Recovering?

Recent studies have shown that fatal white shark bites have increasingly become the leading cause of sea otter mortality in California, a concerning trend that is likely impacting range expansion and population recovery. Scientists also attribute a substantial percentage of southern sea otter mortality to infectious diseases, many of which are known to have anthropogenic causes and land-to-sea linkages. White shark bites, pathogens and parasites, food availability, nutritional deficiencies, habitat degradation, coastal pollutants and contaminant exposure are among many of the contributing factors threatening the recovery of the species. And the risk of a major oil spill remains a serious threat.

What’s Being Done About It?

Researchers are working hard to gain a better understanding of what’s threatening sea otters so we can find ways to help them recover. Determining precisely how all of the factors driving elevated mortality are impacting the overall health of the southern sea otter population and the nearshore marine ecosystem on which they and other species depend is critical. The goal is development and implementation of effective, long-term management and mitigation strategies that can lead to the recovery and delisting of the species.

Threats and Issues

White Sharks

The single greatest cause of southern sea otter mortality by far is fatal white shark bites. Shark-bitten sea otters now account for more than half of all stranded sea otters recovered in California, exceeding all other causes of sea otter mortality combined. The increase in shark bite mortality now appears to be impacting population growth and expansion at the peripheries of the range, areas of the population that typically fuel the colonization of new habitats. Sea otter range expansion to the north and south will be critical for full recovery of the population but unfortunately these are the very areas where increased shark bite mortality has been greatest.

Disease and Contaminants

California’s sea otters acquire many infectious diseases because of elevated pathogen and contaminant pollution levels in nearshore waters. Part of sea otters’ high susceptibility to exposure is due to their diet. With incredibly high energy requirements, sea otters must consume approximately 25% of their bodyweight in prey each day just to stay alive. A large proportion of this prey consists of filter-feeders, such as mussels and clams. These organisms indiscriminately sieve particles out of the water and can accumulate high concentrations of pollutants and disease pathogens. When otters repeatedly forage on these contaminated prey, over time they can expose themselves to harmful or even lethal doses.

Oil Spills
Human Disturbance

Sea otter harassment and other wildlife disturbance represents more than 40 percent of all violations recorded annually in Monterey Bay National Marine Sanctuary. The harmful consequences harassment can potentially have on sea otter adult females, especially those caring for pups, is particularly concerning. The demanding maternal costs associated with pup rearing for adult female sea otters make them exceptionally vulnerable to energetic deficits — this includes the additional energy expenditure caused by harassment by humans. I f a resting otter is harassed and forced to dive, the animal must expend additional energy to swim away only to begin grooming all over again, which takes away precious time it would otherwise have to rest or care for its young undisturbed. Research has revealed that females with 6 month old pups spend up to 14 hours a day foraging, while consuming nearly twice as much food as females with no pups. Their daily energetic demands are challenging enough, but superimpose harassment on top of an already strenuous energy budget and it may be ultimately too much for the animals to overcome, making them more vulnerable to infection and disease, and increase the likelihood they abandon their pups as they aren’t able to provide for them.

California Sea Otter Fund: $3 Million and Counting

Since it’s inception in 2007, the California Sea Otter Fund has provided critical support for sea otter research and conservation. The Fund has raised over $3 million through the generous and continued support of otter-loving Californians. Each year the Fund must meet a target goal in order to stay on the tax form the following year so please consider making a tax-deductible donation to the California Sea Otter Fund when you file your state income taxes, even if it’s a small amount. The money raised goes to the California Department of Fish and Wildlife and California Coastal Conservancy to fund research focusing on what’s threatening sea otter population recovery, public outreach and education, and ongoing investigations into sea otter harassment.

Californians, please remember sea otters when you file your taxes. Look for line 410 on Form 540. With only 3,000 southern sea otters left in the wild today, every otter counts!


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Research output : Contribution to journal › Article › peer-review

T1 - Sea otters (enhydra lutris) from the northern and southern populations may find each other in Humboldt County, California

N1 - Publisher Copyright: © 2019 IUCN Otter Specialist Group.

N2 - Sea otters (Enhydra lutris) are an apex carnivore and a keystone species, whose range contracted with population declines in last few centuries. But due to direct conservation efforts, both the northern sea otter (E. lutris kenyoni) and southern sea otter (E. lutris nereis) populations shown increases in the last few decades. The two populations are not connected, however, and southern sea otters in California are still threatened and endangered on the state level. The Humboldt County coast is situated between the southern sea otters in central California and the northern sea otters found between Oregon and Alaska. In 2015 a sea otter was seen in Humboldt Bay, the first sighting in Humboldt County since 2005. Although most sea otters found in Humboldt County are assumed to be from the southern sea otter population, genetic testing of a dead sea otter found in 2014 determined that it was from the northern sea otter population. The continued documentation of southern sea otters and the recent documentation of dead northern sea otter in Humboldt County suggests the Humboldt County coast may be an important area for linking the two populations in the future.

AB - Sea otters (Enhydra lutris) are an apex carnivore and a keystone species, whose range contracted with population declines in last few centuries. But due to direct conservation efforts, both the northern sea otter (E. lutris kenyoni) and southern sea otter (E. lutris nereis) populations shown increases in the last few decades. The two populations are not connected, however, and southern sea otters in California are still threatened and endangered on the state level. The Humboldt County coast is situated between the southern sea otters in central California and the northern sea otters found between Oregon and Alaska. In 2015 a sea otter was seen in Humboldt Bay, the first sighting in Humboldt County since 2005. Although most sea otters found in Humboldt County are assumed to be from the southern sea otter population, genetic testing of a dead sea otter found in 2014 determined that it was from the northern sea otter population. The continued documentation of southern sea otters and the recent documentation of dead northern sea otter in Humboldt County suggests the Humboldt County coast may be an important area for linking the two populations in the future.


Watch the video: Sea Otters LIVE Behind the Scenes. #SheddTalksMinis (June 2022).


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