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. 5:510. doi: 10.3389/fmars.2018.00510. 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. Cyclical changes in ocean climate or emerging changes due to climate change (e.g., ocean temperature, acidification) could significantly influence invertebrate populations on which sea otters depend by affecting either transport and recruitment of pelagic larvae (Menge et al., 1997, 2009) or survival and growth of recruits and adults on the benthos (Bodkin et al., 2018). Population expansion occurred initially through protection from hunting and later through reintroductions with varying degrees of success. After 12 weeks of being fed and groomed, a pup is considered a juvenile, Behavioral Traits and Conservation Status. U.S. Geological Survey Scientific Investigations Report 20095045. Proc. 23, 202210. A., Conrad, P. A., Staedler, M., Miller, M. A., et al. Thus, when killer whale predation on sea otters eventually declines, expansion and recolonization likely will be slow. B. College Park, MD: National Archives and Records Administration, 75266. What is the trend between 15-30 years in the sea otter population? Official websites use .gov 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. Through increases in kelp production arising from sea otters reduction of herbivorous invertebrates or increases in seagrass distribution and abundance arising from their reduction of cancrid (crabs in the Family Cancridae) predators of mesograzers on algal epiphytes, sea otter predation can benefit lingcod (Ophiodon elongatus), kelp greenling (Hexagrammos decagrammus), and several species of rockfish (Sebastes and Scorpaenichthys) (Markel, 2011; Hughes et al., 2013; Markel and Shurin, 2015). Technical Report No. Am. doi: 10.1016/j.ijpara.2003.12.008, Monson, D., Estes, J. EXAMPLE: the sea otters, kelp, urchins, and sharks living together in La Push Students also viewed Ecol. Sci. doi: 10.1016/j.tree.2008.01.003. D. Genetically, the southwest Alaskan DPS shows a population structure typical of isolation by distance (USFWS, Anchorage, AK, United States) reflecting the limited dispersal distances of sea otters (Tarjan and Tinker, 2016). A., Hatfield, B. >> Proc. In addition, the GWA program evaluates various tractable performance metrics for key species such as survival rates, size distributions and diets. This pattern suggests that Gulf-wide mortality factors are influencing large mussel abundance, whereas site-specific factors are influencing the settlement and survival of smaller mussels (Bodkin et al., 2018). Along the west coast of North America, they remained absent from eastern Prince William Sound in Alaska to central California- a linear distance of approximately 4,000 km of nearshore habitat where they formerly existed. Herrick, Jr, and Hanan, D. (1988). Look in the library and on the Internet to learn what animals live in a kelp forest. Wildl. Prog. Sea otters were presumed extinct in California after the 19th century fur trade years, but were rediscovered in the 1930s by the public, when as few as 50 animals were documented persisting in nearshore areas off the coast of Big Sur. 111 , .. . The most recent estimate of sea otter population abundance in Washington was 2,785 individuals (2,632 independents, 153 pups; Jeffries et al. (2002). Sea otters are one of the smallest marine mammals in the world, yet they are the largest member of the weasel family. 2), (2) the extent to which current density varies among locations, . Between 1911, when hunting was prohibited, and 1972, when the MMPA was passed, these otters recolonized more than 200 miles (370 kilometers) of the California coast. PDF documents opened from your (5) Evaluating the conservation benefits of sea otter translocations: The first successful efforts to restore sea otters to parts of their range took place from the mid-1960s to the early 1970s. Future research should focus on developing technology to determine sea otter dispersal distances in both predator-impacted areas (i.e., the Aleutian Islands) and areas without significant predation pressure. When you are finished take a picture of your graphs and submit them with the assignment. As sea otter populations continue to expand in their range and numbers, monitoring will become increasingly challenging, likely resulting in reduced effort and statistical power to detect change (Williams et al., 2018). In addition, sea otters in the western Aleutian Islands have likely experienced strong selection against dispersal [i.e., dispersers were/are more likely to be eliminated by killer whale predation (see Question 7); Willems and Hill, 2009; Lapiedra et al., 2018], potentially making recovery and reoccupation even more difficult in the future. doi: 10.1890/08-0765.1, Williams, P. J., Hooten, M. B., Womble, J. N., Esslinger, G. G., and Bower, M. R. (2018). Moreover, white shark bites now account for >50% of recovered carcasses in California, with shark predation now limiting population expansion to the south as well as the north (Tinker et al., 2016). doi: 10.1002/ecs2.1604, Lensink, C. J. The authors recognize the support they have received from their respective institutions and numerous colleagues and students over many years, which made this article possible. PLoS One 11:e0150547. An unusual genotype of Toxoplasma gondii is common in California sea otters (Enhydra lutris nereis) and is a cause of mortality. Sea otter density at large spatial scales is a mosaic of local densities that depend on many factors and vary over different time scales. Mar. Monitoring efforts have varied in frequency and type across years. doi: 10.1111/eva.12642, Garshelis, D. L., Johnson, A. M., and Garshelis, J. Marine mariculture may represent an alternative to the commercial and subsistence shellfish fisheries that cannot be sustained in the presence of sea otters. Gagne, R. B., Tinker, M. T., Gustafson, K. D., Ralls, K., Larson, S., Tarjan, L. M., et al. Why do you think sea otters have done better in Washington State than in other areas, such as Oregon and Northern Mexico, where the animals once lived? Within the western Aleutian Islands, only a few areas with concentrations of sea otters remain (i.e., hotspots), generally within complex, nearshore reef habitats or lagoons that protect the surviving animals from predation. Describe your experience. Patterns of mortality in southern sea otters (Anhydrates lutris nereis) from 19982001. /Type /ExtGState After protection in 1911, these remnant populations expanded across open water up to 50 km to reoccupy neighboring islands (Lensink, 1960). 5 0 obj What is the general trend in the sea otter population that is seen between 0-15 years? Int J. Parasitol. What would you do? Science 200, 403411. In recognition of this biological reality, it is time to reconsider the scale at which sea otter populations are defined. The population has grown by about 10 percent per year over the past decade and contained about 100 otters in 2019. doi: 10.7589/0090-3558-39.3.495, Krkosek, M., Lauzon-Guay, J. S., and Lewis, M. A. 8:e2852. Appl. Explore recent publications by USGS authors, Browse all of Pubs Warehouse by publication type and year, Descriptions of US Geological Survey Report Series, Southern (California) sea otter population status and trends at San Nicolas Island, 20172020, Appendix 1. A., and Levin, S. A. However, it is likely that subpopulations within MUs are functionally independent as well. He thereafter lingers in a coma for 2 months and then dies. SL wrote Question 5. *Correspondence: Randall W. Davis, davisr@tamug.edu, Future Directions in Research on Marine Megafauna, View all Nat. A., and Duggins, D.O. (2013). Adult male Alaskan otters weigh 27 to 39 kg, while females weigh 16 to 27 kg. As sea otter populations have recovered, they have come into contact and sometimes conflict with human activities that developed during the more than 100 years when the sea otter was ecologically extinct as a keystone species in the nearshore (Estes and VanBlaricom, 1985; Wendell et al., 1986b; Wendell, 1994; Watson and Smith, 1996; Larson et al., 2013; Hoyt, 2015). Growth - The Sea Otter Population Growth Historical Data Figure 1: Sea otter population measured off the coast of Vancouver Island Sea otters once ranged from Northern Japan to central Baja California, and had an estimated global population of between 150,000 and 300,000. (1978). Dis. Yee, J.L., Tomoleoni, J.A., Kenner, M.C., Fujii, J., Bentall, G.B., Tinker, M.T., and Hatfield, B.B., 2020, Southern (California) sea otter population status and trends at San Nicolas Island, 20172020: U.S. Geological Survey Open-File Report 20201115, 38 p., https://doi.org/10.3133/ofr20201115. What is the general trend in the kelp population that is seen between 0-20 years? This example provides direction for future research and monitoring to address management goals. stream 39, 495509. As the population expanded both north and south into habitat that was not observable from shore, aircraft were used for surveys. 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. Sea otters can see clearly above and below the water and have good senses of smell and hearing. RD organized and integrated this article and wrote the Introduction, Question 2, and the Conclusion and Recommendations. However, available information is often inadequate for managers to conduct meaningful analyses or to anticipate and mitigate conflicts before they occur. Acad. Initially, remnant populations were small and occupied small ranges, enabling surveys that could be conducted from skiffs with limited personnel and time. 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. Estes, J. J. Mammal. Manage. doi: 10.2307/3672835, Reidy, R. D., and Cox, S. P. (2013). The past few decades have demonstrated that sea otter populations can be strongly influenced by the top-down pressure of higher-level predators, and this change in perspective should be acknowledged in management strategies. ELKHORN SLOUGH SEA OTTER RESEARCH - OF ESTUARIES AND SEA OTTERS. Other land-based predators that have been documented preying on sea otters include brown bears (Ursus arctos) on Russias Kamchatka Peninsula, along the Alaska Peninsula, and on Kodiak Island (Bednykh et al., 1986; Monson and DeGange, 1995). Hyg. Course Hero is not sponsored or endorsed by any college or university. Alaska Natives can hunt sea otters legally but cannot sell unaltered pelts. J. Wildl. For best results viewing and printing PDF documents, it is recommended that you download Management applications include possible translocations around shark barriers in California to restart population expansion and among hotspots in the western Aleutian Islands to maintain gene flow and genetic health. doi: 10.1371/journal.pone.0091235, Hatfield, B. (1988). 35, 11551168. A., Underwood, K. E., and Karmann, M. J. J. Exp. 4) This article was a collaborative effort by all authors. Endanger. Translocations into historical habitat often showed rapid growth, enhanced genetic diversity and connectivity, and restoration of nearshore community structure and biodiversity. Intuitively this explanation makes sense, but it took decades for biologists to fully realize how a population functioning at small spatial scales in conjunction with shoreline complexity could explain the relatively slow growth of the California population, which for decades was a source of concern for sea otter researchers and conservation organizations. SOP for Monitoring Intertidal Bivalves on Mixed-Sediment Beaches - Version 2.0: Southwest Alaska Inventory and Monitoring Network. PLoS One 8:e82477. 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. While sea otters are vulnerable to natural predators such as sharks, the population also faces risks from other factors such as disease, contaminants, harmful algal blooms, availability of prey, and entanglement in commercial fishing gear. Estes, J. Intraperitoneal satellite transmitters do not exist because of antenna limitations. /ca 1.0 History and status of translocated sea otter populations in North America. doi: 10.1038/nclimate1944, Atwood, T. B., Connolly, R. M., Ritchie, E. G., Lovelock, C. E., Heithaus, M. R., Hays, G. C., et al. doi: 10.1016/B978-0-12-801402-8.00001-9, Larson, S. E., Ralls, K., and Ernest, H. (2015). The overall sea otter population size of the Southwest Alaska stock has declined by more than 50% since the mid-1980s. doi: 10.1111/j.1748-7692.2005.tb01218.x, Estes, J. (3) Quantifying the effects of sea otters on the littoral community: Consideration should be given to how food availability limits population and ecosystem recovery and on predicting the effect of sea otter reoccupation on commercially valuable resources. (2) Understanding factors that regulate sea otter population density: Sea otter density at the landscape scale is a mosaic of local densities that depend on many factors, which vary over different time scales. 17, 632647. Coinciding with recent population growth, the sea otter distribution, which previously tended to concentrate on the west side, appears to have shifted toward an expansion of use in the north and especially greater seasonal use in the north and south during winter and spring. Mol. To reduce the risk of a large oil spill contacting otters throughout all or much of the species range, the FWS, in the late 1980s, attempted to establish a separate population at San Nicolas Island through a translocation of otters from the parent range. Click to download the free sample version, Sea otters are adorable and fascinating little, Average Lifespan in the Wild: 15 -20 years, Average Size: 3 ft 11 in 4 ft 11 in (1.2 1.5 m), Average Weight: 30 100 lb (14 45 kg ), Male sea otters are called boars, females are sows, and newborns are pups, Subspecies Three subspecies of the sea otter are recognized. B., and Murphey, T. G. (2000). A lock () or https:// means youve safely connected to the .gov website. 1982; Jameson et al. Sea otters rely on their fur for insulation, which cannot be compromised by the attachment of external satellite telemeters used with many other marine mammal species. Ecol. However, within most of the sea otters range, shore counts are not possible due to restricted access. Nat. For sea otters, dispersal distance is one of the least studied aspects of their biology, and developing new technologies to study dispersal should be a high priority for future research. While these two examples focus on the recolonization by sea otters of areas without fisheries conflicts, existing long-term monitoring programs, such as GWA, should guide the development of research questions that focus on the effects of recolonization on commercially viable prey species. Predicting ecological consequences of marine top predator declines. } !1AQa"q2#BR$3br browser may not display or print as intended. The sea otter spends most of its time in the water but, in some locations, comes ashore to sleep or rest. International legal protection and translocations in the 20th century have enabled sea otters to recover and reoccupy historical habitats with varying levels of success. 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