Sea otter mortality due to shark attacks has increased since 2003, with a threefold to eightfold increase in the probability of a stranded carcass being shark bitten depending on location (Tinker et al., 2016). 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). Conflicts between sea otters and fisheries also can take the form of by-catch risk for sea otters. These results can be useful to the planning of future monitoring and research of sea otters at San Nicolas Island. In 2017, the U.S. Navy and the U.S. Ecol. Secondly, the few remaining sea otter hotspots have small effective population sizes at risk of additional losses of genetic diversity. 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. Loss of genetic diversity in sea otters (Enhydra lutris) associated with the fur trade of the 18th and 19th centuries. Johnson, C. K., Tinker, M. T., Estes, J. Estimates of energy intake rates averaged 17.3 kilocalories per minute (95-percent confidence interval =15.619.0 kilocalories per minute) and suggest possible variations across years and seasons, but confidence intervals based on specific years of data were relatively wide. Bull. What could be some possible hypotheses for why the kelp population is changing? However, in the 1700s and. Amanda thereafter runs into a nearby alley and hides behind a dumpster. When otters are present, urchins hide in crevices and snack on kelp scraps. However, little evidence exists of population monitoring during the commercial fur trade era beyond harvest records (Lensink, 1960). Does tiger shark predation risk influence foraging habitat use by bottlenose dolphins at multiple spatial scales? Science 185, 10581060. This is a fantastic bundle that includes everything you need to know about sea otters across 25 in-depth pages. Microbiol. The females raise their young without any assistance from the males. In contrast, areas to the east still have healthy, growing populations, including those along the southern Alaska Peninsula (Coletti et al., 2016) and Kodiak Island (Monson and DeGange, 1995). 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. Most notable are the nearshore areas: (1) between Northern Japan and throughout the east coast of Sakhalin Island, Russia (1,000 km); (2) between the southern portion of Southeast Alaska and parts of British Columbia (400 km); (3) between central Washington State (the current southern range limit of the northern sea otter) and midway between Monterey Bay and San Francisco Bay, CA, United States (the current northern range limit of the southern sea otter; 1,500 km); and (4) south of Santa Barbara, CA, United States (the current southern range limit of the southern sea otter) and central Baja California (800 km) (Larson and Bodkin, 2015). WERC's sea otter researchers are developing and utilizing a variety of methodological and analytical tools to understand the causes of biological and ecological trends in sea otter populations, and to predict the ecological consequences of management practices on these populations and their ecosystems. Conserv. A., Chan, F., Nielsen, K. J., Lorenzo, E. D., and Lubchenco, J. doi: 10.1111/j.1748-7692.2003.tb01102.x, Estes, J. An unusual genotype of Toxoplasma gondii is common in California sea otters (Enhydra lutris nereis) and is a cause of mortality. Ser. '3 i]']&lExZ BX"!p+aL6IAnU/DaFLU7 0N$0b/ vqfSs[3fBaISS%;v]I~_?^t.8rjGJ>q8hO]%wGx5DMM-1L/uJ9ttRaw}Z 2Jb K[&x6k >E^[m$1fRcV6q)Y4IDnqpzwhPreoRlY~YoAG.3\0L\HU"!hm(ekpjm LcXT4q. Incorporating diverse data and realistic complexity into demographic estimation procedures for sea otters. Two sea otter subspecies occur in the United States, the southern sea otter (Enhydra lutris nereis) and thenorthern sea otter(E.l. kenyoni). /SMask /None>> 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. doi: 10.1007/s00442-014-3149-6, Szpak, P., Orchard, T. J., McKechnie, I., and Grcke, D. R. (2012). Reliable information on sea otter population growth and range expansion is needed to enable communities to adapt as shellfish fisheries are impacted. Among the northern population, female sea otters give birth between May and June, while southern populations are between January and March. The threat to the southern sea otter posed by oil spills prompted its listing as a threatened species in 1977. J. Anim. The geographic range of sea otters has fluctuated over the last 300 years. 6 in southwestern Alaska began to suffer dramatic declines. When prepared and cooked correctly, it makes a healthy, tasty stew. 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). doi: 10.3354/esr00327, Hattori, K., Kawabe, I., Mizuno, A. W., and Ohtaishi, N. (2005). Mol. Benthicpelagic links and rocky intertidal communities: bottom-up effects on top-down control? A., Hatfield, B. endobj These measures are essential because they are sensitive indicators of population and environmental change and provide insights into the mechanisms of change (e.g., distinguishing food resource limitation from the effects of physical disturbance, disease, or predation pressure). Sci. Bald eagles and sea otters in the Aleutian Archipelago: indirect effects of trophic cascades. Sci. Geographic variation in sea otters, Enhydra lutris. In addition, translocating sea otters (see Question 5) beyond areas where shark-bite mortality is especially high in California would allow for additional expansion of the southern sea otter population while translocations among Aleutian Island populations could maintain genetic exchange and heterozygosity within the remaining sea otter hotspots. Critique of the evolutionarily significant unit as a definition for distinct population segments under the US endangered Species act. Sea otters were once widespread across coastal waters in the Northern Pacific Ocean, from Baja California to Alaska, all the way to rocky reefs in Russia and Japan. Sci. From this perspective, the focus would be on predicting the effect of sea otter reoccupation on commercially valuable resources (see Question 6). A., Estes, J. History and status of translocated sea otter populations in North America. Mar. Growth and equilibrium in sea otter populations. The declining mainland counts since 2017 could be due to increased mortality from shark bites and other causes such as harmful algal blooms and disease. doi: 10.1046/j.1523-1739.1997.96109.x, Raimondi, P., Jurgens, L. J., and Tinker, M. T. (2015). Sea otter feeding on a California sea cucumber (Apostichopus californicus). thesis, University of Minnesota, St. Paul, MN. Home Facts Privacy About Blog Contact Terms. Trends in Sea Otter Population Abundance in Western Prince William Sound, Alaska: Progress Toward Recovery Following the 1989 Exxon Valdez Oil Spill . Ph.D. thesis, University of British Columbia, Vancouver. Ecol. T. R. Loughlin (San Diego, CA: Academic Press), 4759. Additional resources (found in trunk) that can be used to supplement reading articles: 1. doi: 10.1111/eva.12642, Garshelis, D. L., Johnson, A. M., and Garshelis, J. The POC that is produced in the spring bloom may be a source of carbon that circulates in the water column for the remainder of the year, while the kelp provides a continuous source of carbon even in the winter when there is negligible phytoplankton productivity (Tallis, 2009). This is an interactive unit study to reinforce Middle through High School Math, Algebra, Geometry, Math and Cooking principles in an engaging, real life format. Ecology 96, 28772890. Considering (1) that the 2000 Their food is usually filter feeders Why go to all the effort to save sea otters? 52, 7076. Before commercial hunting began in the mid-1700s, an estimated 150,000 to 300,000 sea otters occurred in coastal waters throughout the North Pacific Ocean. Approximately how much have sea otter populations increased from 1969-70 to today? Diseases (Toxoplasma gondii in California and Streptococcus Syndrome in parts of Alaska) also may have a density-dependent effect on local populations (Johnson et al., 2009; Mazzillo et al., 2013; Van Wormer et al., 2014; Counihan et al., 2015; Bartlett et al., 2016). Society for Science & the Public 20002023. In addition, new technology is needed to remotely track individual animals at larger spatial and temporal scales with increased accuracy. The average adult sea otter must eat 20 to 30 percent of its body mass in food each day just to meet its energy requirements. Dean, T. A., and Bodkin, J. L. (2011). doi: 10.1111/j.1748-7692.1993.tb00441.x, Kvitek, R. G., and Oliver, J. S. (1992). doi: 10.1016/j.tpb.2007.01.008, Kvitek, R. G., Bowlby, C. E., and Staedler, M. (1993). The development of commercial and recreational shellfish fisheries was fueled by the high abundance of benthic invertebrates that developed during the absence of their natural predator, the sea otter. The diet of sea otters in the KEJF includes a high proportion of intertidal mussels (58%), which have experienced a period of decline and subsequent recovery despite consistent site-specific settlement of small mussels over time (Coletti et al., 2016; Bodkin et al., 2018). As further range expansion continued, the proportion of the population surveyed by shore and air continued to change, with less survey effort from shore, where detection probability is high, to more survey effort from the air, where detection probability is lower, with potential implications for the interpretation of population trends. 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