Gorbics, C. S., and Bodkin, J. L. (2001). Ph.D. thesis, University of California, Santa Cruz, CA. Bull. w !1AQaq"2B #3Rbr The geographic range of sea otters has fluctuated over the last 300 years. Mar. The first efforts to restore sea otters to parts of their historical range took place from the mid-1960s to the early 1970s in a series of translocations from Amchitka Island and Prince William Sound to the Pribilof Islands in Alaska, Southeast Alaska, Vancouver Island in British Columbia, and Washington and Oregon states (Jameson et al., 1982). They live in wet areas such as coastlines, oceans, and marshes of all continents except. The total economic value framework used in environmental economics additionally recognizes non-use value, which comprises existence value (the benefit obtained from knowing a species continues to exist) and bequest value (the value of preservation so that opportunities for use or observation will exist in the future). Evidence that this decline is due to the top-down effects of killer whales includes the following: (1) the observed rate of killer whale predation events is consistent with the expected frequency relative to observer effort, (2) declines have occurred in outer coastal habitats but not within lagoon habitats inaccessible to killer whales (e.g., Clam Lagoon on Adak Island), (3) carcasses deposition on beaches has not increased during the decline (i.e., sea otters consumed entirely), (4) energetic calculations show that only a small number of killer whales could explain the decline (i.e., it is feasible that one pod caused the entire decline), (5) the geographic extent of the decline indicates that the cause is not localized (i.e., not from a point-source of contaminants), (6) the lack of evidence of disease or toxins in live-captured animals indicates that disease is not the cause, (7) there has been a dramatic nearshore shift (to within 100 m from shore) in sea otter distribution with the only remaining areas of outer coast sea otter concentrations (hotspots) characterized by shallow, complex reef habitats that are less accessible to killer whales, and (8) sea otter behavior when disturbed has changed (i.e., before the decline sea otters would move offshore, but after the decline they move close to shore or haul out). The effects of sea otters on commercial, recreational, and subsistence shellfish fisheries (Estes and VanBlaricom, 1985; Wendell et al., 1986b; Wendell, 1994; Watson and Smith, 1996; Larson et al., 2013; Hoyt, 2015) due to competition for prey have been among the most highly visible and politically charged of sea otters interactions with human activities (Carswell et al., 2015). Several abalone species are listed under endangered species legislation in Canada and in the United States,1 and other species may join the ranks depending on how well fisheries are managed. What is the trend between 15-30 years in the sea otter population? >> Watson, J. C., and Smith, T. G. (1996). 17, 632647. The second perspective focuses on the near-term impact of sea otters on large invertebrates (e.g., clams, crabs and urchins) that flourished in their absence and enabled economically and culturally important fisheries to thrive. The North Pacific Fur Seal Treaty of 1911, which included sea otters, offered the first legal protection for sea otters in at least some parts of their range (Nichol, 2015) and initiated active, multi-national management so that the species could recover. (PDF). Furthermore, an abundance of urchins (a primary sea otter prey) in habitats where sea otters disappeared (Stewart et al., 2015) and an increase in the body size of sea otters during the decline do not indicate that bottom-up influences are responsible (Laidre et al., 2006; Monson, 2009). Organizations engaged in sea otter management and conservation will benefit from collaboratively designing sea otter monitoring protocols across the North Pacific that will optimize efforts, enable the detection of trends and causes, and provide for spatial contrasts of those variables over time (Coletti et al., 2016). A., Ricca, M. A., Miles, A. K., and Forsman, E. D. (2008). However, genetic variability is highest in the Southeast Alaska population, which was created by translocations from two widely separated source populations including Prince William Sound and Amchitka Island (Jameson et al., 1982; Larson et al., 2002a). "Keep Sea Otters in the Picture" poster (Sea Otter History, Web of Life, Sea . The main threat to sea otters used to be hunting by native people who used their meat as food and their fur for clothing. 35, 11551168. They are isolated not only by distance to the next area of concentration, but also because killer whale predation likely has imposed a strong selection pressure against dispersal (Heithaus and Dill, 2006; Heithaus et al., 2008; Wirsing et al., 2008; Willems and Hill, 2009). Zool. (2014). A total of 139 wild sea otters were translocated. Management options to mitigate the effects of sea otters on fisheries do not include reducing sea otter populations through harvests or culls. The sea otter population decline in the western Aleutian Islands prompted the United States Fish and Wildlife Service to designate this stock as threatened under the United States Endangered Species Act in 2005. J. Trop. Markel, R. W. (2011). Dramatic increase in sea otter mortality from white sharks in California. %PDF-1.7 Population Dynamics and Foraging Ecology of Northern Sea Otters (Enhydra lutr. 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. Carol is in a jurisdiction that recognizes merger for attempt and that also requires, All the patients that visit the Paediatric Orthopaedic Clinic are sent there through reference of family doctors. After their near extirpation, remnant sea otter populations and those that resulted from reintroduction were below carrying capacity and experienced a period of logistic growth. -;I%bo[Qg. doi: 10.1126/science.aap9289, Larson, S., Jameson, R., Bodkin, J., Staedler, M., and Bentzen, P. (2002a). Fort Collins, CO: National Park Service. Status and Trends of Sea Otter Populations in Southeast Alaska, 19692003. Loss of genetic diversity in sea otters (Enhydra lutris) associated with the fur trade of the 18th and 19th centuries. stream Census counts may be made from shore, the water or the air. From those sites, we may be able to extrapolate throughout the sea otters range. U.S. Geological Survey Scientific Investigations Report 20095045. To minimize the potential for disturbance and harm to sea otters, people sharing sea otter habitat should: Aquat. Sydney Institute of Marine Science, Faculty of Science, University of New South Wales, Australia, San Francisco Bay Bird Observatory, United States. Nat. Other populations, such as the one in California, experienced more modest growth (Estes et al., 2003; see Question 1). doi: 10.2307/1376352. Sci. Elkhorn Slough National Estuarine Research Reserve, Biologist & Southwest Region Dive Safety Officer, 12201 Sunrise Valley Drive Reston, VA 20192, Western Ecological Research Center (WERC). Predators help protect carbon stocks in blue carbon ecosystems. As a result, research will need to focus on a few sites that are representative of the variety of littoral habitats occupied by sea otters around the North Pacific Rim. Sato, C. L. (2018). The southern sea otter (Enhydra lutris nereis) population at San Nicolas Island, California, has been monitored annually since the translocation of 140 sea otters to the island was completed in 1990. doi: 10.1111/mms.12261, Traiger, S. B., Konar, B., Doroff, A., and McCaslin, L. (2016). Natural Resource Report NPS/SWAN/NRR 2014/756. NEW! Clim. 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), 117. /Filter /DCTDecode Accordingly, this project aims to understand the impact of multiple threats on sea otter abundance and trends, describe critical sea otter habitat needs, and determine the functional roles of sea otters in nearshore ecosystems. J. Arch. 8:e2852. (Theresa Soley/KTOO) John Ryan lives in Hollis, on Prince of Wales Island. 57, 199203. In 2017, the U.S. Navy and the U.S. doi: 10.1016/j.jas.2011.12.006, Tallis, H. (2009). Sea otters are a keystone predator in the nearshore food web of the north Pacific Rim (Estes and Duggins, 1995). Well-known examples are sea otter populations in the Aleutian Islands prior to their subsequent decline in the 1990s, as well as populations in Southeast Alaska and Washington State (Bodkin et al., 1999). (2002). doi: 10.1016/j.jembe.2015.05.020, Costa, D. P., and Kooyman, G. L. (1984). Sea urchins and abalone are depleted quickly because they are highly accessible and relatively immobile, whereas geoducksa species of bivalve that burrows deeply in soft sediment and can occur in deep waterare depleted at a slower rate (Kvitek and Oliver, 1992; Kvitek et al., 1993; Watson and Smith, 1996; Reidy and Cox, 2013; Hoyt, 2015). Biol. Consequently, the frequency of large scale surveys in areas such as Southeast Alaska and the Aleutian Islands declined to decadal intervals. Course Hero member to access this document, Lia_Rudisill_-_1_extracted_Homeostasis_Population_Graphs_CC.pdf, Copy of Population Trends - Group Collaboration Form.pdf, 459F3086-450C-4285-BF3B-B97159FE769F.jpeg, B3D9BE94-7A76-4810-9325-F6E745985E3B.jpeg, Sam Barlow High School BIOLOGY Honors Bio, Sunrise Mountain High School PRE-AP BIOLOGY H 12259, South Pasadena Senior High SCIENCE 101 PG. Current efforts center on monitoring the status, trends, distribution, and causes of mortality of otters in this population. Developing technology is needed to determine dispersal distances in both predator-impacted areas (i.e., the Aleutian Islands) and areas without significant predation pressure to help evaluate translocation needs. (2018). J. Mamm. Understanding the factors that regulate animal density may be one of the most challenging and expensive ecological questions. Sea otters are now protected by law, and their numbers are considered stable. Natural Resource Report NPS/SWAN/NRR2016/1175. Oyster mariculture using net bags or enclosed trays occurs in Kachemak Bay and Prince William Sound, Alaska and on the west coast Vancouver Island, British Columbia, despite the presence of large numbers of sea otters. More recent high-resolution sampling of the southern sea otter population in California did find evidence for isolation by distance and cryptic genetic structure with implications for estimates of effective population size (Gagne et al., 2018). You can use these worksheets as-is, or edit them using Google Slides to make them more specific to your own student ability levels and curriculum standards. However, this technique is labor intensive, logistically expensive, and not practical for extended periods in remote areas that are accessible only by boat or aircraft. 24, 115. For example, in central California, where a higher sea otter density is positively associated with higher black abalone density, sea otter predation may have served to reduce poaching impacts by driving black abalone into deep crevice habitat where they were safe from sea otters and poachers (Raimondi et al., 2015). As a result of the failure finding, there no longer is a legal obligation to try to prevent expansion of the parent populations range south of Point Conception. 56, 701703. J. Wildl. doi: 10.3354/meps08138, Tarjan, L. M., and Tinker, M. T. (2016). (2012). doi: 10.1007/s00442-014-3149-6, Szpak, P., Orchard, T. J., McKechnie, I., and Grcke, D. R. (2012). Population demographics and genetic diversity in remnant and translocated populations of sea otters. Ecol. Mar. Mamm. A., Kurz, W. A., Holtgrieve, G. W., Ritchie, M. E., et al. Fish and Wildlife Service. 131, 526543. Fort Collins, CO: National Park Service. 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