doi: 10.1111/mms.12261, Traiger, S. B., Konar, B., Doroff, A., and McCaslin, L. (2016). Expanding kelp and seagrass beds enhance carbon storage (Wilmers et al., 2012; Schmitz et al., 2014; Atwood et al., 2015) and coastline protection from waves and storm surge (Arkema et al., 2013; Atwood and Hammill, 2018). The population has continued to decline, with a most recent abundance estimate of 2,962 otters in 2019. 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. In the first 10 years, at what point did carrying capacity appear to be? Hughes, B. Nat. A., et al. A. 17. For many years, the central question driving research in California was why this population was growing so slowly. These results can be useful to the planning of future monitoring and research of sea otters at San Nicolas Island. Int J. Parasitol. These aquatic members of the weasel family are often seen floating on their backs. They live in wet areas such as coastlines, oceans, and marshes of all continents except. Relating dispersal and range expansion of California sea otters. doi: 10.2307/1379491, Simenstad, C. A., Estes, J. It inhabits coastal waters from the Kuril Islands to the Aleutian Islands southward to the coast of California. Information is also needed on the beneficial effects of: (1) sea otter-induced trophic cascades on finfish populations and fisheries, (2) enhanced kelp and seagrass beds that reduce shoreline erosion, and (3) atmospheric carbon sequestration provided by expanding kelp and seagrass beds. Their hind feet are webbed to aid in swimming, and their front toes are short and stiff. In nearly all areas occupied by sea otters, primary production is provided by two pathways. Fish and Wildlife Service. Sea otters now are established (with significant gaps) from northern Japan to southern California. (2003). A. What kinds of other animals share the sea otters habitat? 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. Mar. Figure 1. Harvest of sea otters in the United States is strictly limited to coastal Alaska Natives who can take sea otters for subsistence and for creating and selling authentic native handicrafts. Mamm. Stock structure of sea otters (Enhydra lutris kenyoni) in Alaska. 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. 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). Official websites use .gov 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. Restoration of kelp forests in the nearshore increases biodiversity by moving the ecosystem from one dominated by sea urchin barrens to one characterized by a wide variety of kelp-dependent species of invertebrates, fishes and seabirds (Estes, 2015). The Sea Otter (Enhydra lutris): Behavior, Ecology and Natural History. Fish and Wildlife Service. A., Ricca, M. A., Miles, A. K., and Forsman, E. D. (2008). With no more otters to eat them, the sea urchins, which eat the Received: 02 July 2018; Accepted: 21 December 2018;Published: 21 January 2019. d7f;?VF+! 8fpbP`T%npZU5Xp{AHa" O1J%t#)fnLMnX8'T%"8%E]!R Biol. Gestation is 4 to 5 months, resulting in a single pup that weighs 3 5 lb (1.5 2.5 kgs). Provide a title and lable both the X and Y. doi: 10.3354/meps08138, Tarjan, L. M., and Tinker, M. T. (2016). 30 mil 20 mil 6 mil 0 5 10 15 20 25 30 Years. U.S.A. 100, 1222312228. What could be some possible hypotheses for why the kelp population is changing? doi: 10.7589/0090-3558-39.3.495, Krkosek, M., Lauzon-Guay, J. S., and Lewis, M. A. FWS, U.S. Geological Survey, and their partners are expected to continue to conduct annual abundance surveys and respond to strandings, including conducting necropsies to identify the causes of death for retrieved carcasses. However, there is a delay between the time when sea otters expand into an area and when commercial-scale harvesting of shellfish becomes inviable, the length of which is somewhat species-dependent. Sign Me Up. doi: 10.1126/science.aap9289, Larson, S., Jameson, R., Bodkin, J., Staedler, M., and Bentzen, P. (2002a). /SM 0.02 A Review of California Entangling Net Fisheries, 1981-1986. In contrast, white shark predation has had population-level effects within the southern sea otters range (Tinker et al., 2016). Understanding the factors that regulate animal density may be one of the most challenging and expensive ecological questions. Sea otter pups are susceptible to predation by bald eagles (Haliaeetus leucocephalus) in areas where they co-occur (Sherrod et al., 1975; Anthony et al., 2008). Mamm. Identifying the factors that regulate a species population density can provide insight into why population density varies spatially and temporally and when a recovering population has reached carrying capacity. Historically, sea otters numbered in the hundreds of thousands in the North Pacific Ocean, but due to the fur trade, their numbers plummeted in the early 1900s. However, bottom-up and abiotic processes that influence invertebrate communities also play a role in nearshore ecosystem function and should be considered when designing a nearshore monitoring plan that includes sea otters (Dean et al., 2014). Limited dispersal distances, adult affinity to small home ranges (Tarjan and Tinker, 2016) and food limitations that developed within the core segment of the population limited the number of animals that could emigrate in these two directions. Sydney Institute of Marine Science, Faculty of Science, University of New South Wales, Australia, San Francisco Bay Bird Observatory, United States. 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. Census counts may be made from shore, the water or the air. Proc. q"4\$j$\F,p1*'H`q $UU` FH'[TzVe6sQ=^)f}Ak Natural Resource Report NPS/SWAN/NRR2016/1175. The San Nicolas population remained small (20 animals) for decades, and the translocation program was administratively deemed a failure in the early 2000s (Federal Register 77, 2012; p. 75266). They can swim on their backs easily, and their muscular tail helps them steer and swim. Why isnt the sea otter population now growing as fast as it once was in Washington? Nat. Furthermore, the adjacent translocated populations in British Columbia and Washington states have expanded their range, resulting in overlap and genetic mixing thereby boosting the genetic diversity to 70% of the pre-fur trade level (Larson et al., 2002b, 2012; Larson and Bodkin, 2015; Sato, 2018). Alaska. 52, 7076. Sea otters have webbed feet, water-repellent fur to keep them dry and warm, and nostrils . Ecology 99, 524535. Sources/Usage: Public Domain. 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). Bodkin, J. L., Ballachey, B. E., Cronin, M. A., and Scribner, K. T. (1999). At the largest, the range spanned the entire northern Pacific Rim from Southern California to areas of Japan. 77, 271280. (2012) examined how different management actions (reducing poaching or reducing the sea otter population) would affect population dynamics and found that recovery targets for northern abalone (based on data collected during the period of sea otter absence) were not attainable even when modeled predation by sea otters and poaching of abalone by humans were reduced. Mar. B., Ames, J. doi: 10.1016/B978-0-12-456160-1.50010-2. A. Kolb 156 extinction. An unusual genotype of Toxoplasma gondii is common in California sea otters (Enhydra lutris nereis) and is a cause of mortality. Sea otter feeding on a California sea cucumber (Apostichopus californicus). Sea otters: their role in structuring nearshore communities. *Correspondence: Randall W. Davis, davisr@tamug.edu, Future Directions in Research on Marine Megafauna, View all Sea otters have the densest fur in the animal kingdom, ranging from 250,000 to a million hairs per square inch, which helps insulate them. This partnership of federal, state and local institutions is seeking to increase our understanding of estuary habitat use by sea otters and to help inform the conservation and restoration of suitable habitat and water quality conditions at Elkhorn Slough. Data suggest that mussel bed dynamics may be driven by processes that influence whether or not individuals survive to sizes suitable as sea otter prey, rather than that mussels are driven exclusively by top-down effects of sea otter predation (Coletti et al., 2016). doi: 10.1371/journal.pone.0032205, Larson, S. D., Hoyt, Z. N., Eckert, G. L., and Gill, V. A. stream Ecol. Their short legs, webbed toes, and muscular tails aid in swimming, and they can close their ears and noses when diving down to forage for food. Potential economic benefits include ecotourism in communities affected by sea otter range expansion (Loomis, 2006). When you are finished take a picture of your graphs and submit them with the assignment. Evaluating potential conservation conflicts between two listed species: sea otters and black abalone. They found that a 50% reduction in the poaching of northern abalone was necessary to reach a short-term recovery goal of halting further declines in northern abalone density in the presence of sea otters. Figures of Pages from the Monitoring and Research Plan for Southern Sea Otter Military Readiness Area. Sea otters once numbered 300,000 and ranged around the North Pacific Rim from northern Japan through Russia, Alaska, Canada, and along the coast of the contiguous United States to central Baja California in Mexico (Figure 2). Prog. Interannual changes in productivity can influence the abundance and growth of sea otter prey, which will have an important bottom-up effect on the carrying capacity of an area. doi: 10.1644/1545-1542(2002)083<0893:MDAMDV>2.0.CO;2. These are great stretches of algae, analogous to terrestrial woodlands, in which kelp fills the role of trees. J. Wildl. (2009). What would you do? PLoS One 8:e65435. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the United States Government. Express the amount as a multiple of the imported population and as a percentage. Prey species have evolved ways to avoid predators: fast growing resistant to storm and wave damage support many marine plants and animals Threats to Kelp Forests Giant kelp anchored to ocean floor and grow toward surface: - - - kelp plants What do sea urchins prey on? magazine, are published by the Society for Science, a nonprofit 501(c)(3) membership organization dedicated to public engagement in scientific research and education. [/Pattern /DeviceRGB] 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. 560, 7386. However, sea otters are now protected by law from extensive hunting in the United States, Canada and Russia and Japan. Small numbers of lobsters (26), octopus (16), and abalone (5) also were identified. 73, 11611169. Part 2 Top Stud. Benthicpelagic links and rocky intertidal communities: bottom-up effects on top-down control? Simultaneous examination of sea otters, their prey and ecosystem productivity over space and time will allow us to infer causes of ecosystem change. He thereafter lingers in a coma for 2 months and then dies. (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. Mortality from shark attacks of otters has been more frequent at the northern and southern extremes of populations range and may be a factor in preventing or slowing range expansion of the population into seemingly suitable habitats. This download is exclusively for KidsKonnect Premium members!To download this worksheet, click the button below to signup (it only takes a minute) and you'll be brought right back to this page to start the download! population at San Nicolas Island, California, has been monitored annually since the translocation of 140 sea otters to the island was completed in 1990. Today, almost 90% of the sea otter population lives in the coastal waters of. Proc. Manage. Share sensitive information only on official, secure websites. To find out more, see our cookie policy. The findings and conclusions in this article are those of the author(s) and do not necessarily represent the views of the United States Fish and Wildlife Service. A., Conrad, P. A., Staedler, M., Miller, M. A., et al. An important density-independent factor is primary production, which injects carbon and nutrients into the food web (see Question 3). However, genetic structure also can be influenced by other factors such as past commercial harvests that exterminated stocks, fragmented habitats that limit natural dispersal, and extra-limital dispersal resulting from environmental change or translocation. Sea otters are a keystone predator in the nearshore food web of the north Pacific Rim (Estes and Duggins, 1995). ,? ~YRaFw7B"mE'2RQqBb060/DBG1Ib4p=n2K4 C2R[dqV"e*j "NhvRBwIKkNC{zt3gk_xz,;m-b+arH=[v4!t1d89%H(];T)tl_+/ld)[FC IkHz}(P:L /Producer ( Q t 5 . Ph.D. thesis. May 1, 2018 Analysis of 13 years of demographic and genetic data from 1,006 sea otters to assess multiple effective population size estimators, as well as temporal trends in genetic diversity . Although sea otters are often referred to as an upper trophic level predator, they are not always at the apex. doi: 10.1371/journal.pone.0065435, Springer, A. M., Estes, J. (2014). These complementary sources of carbon provide some resilience to species of suspension feeding invertebrates that depend on particulate organic carbon (POC). Presumably the increase in attacks on sea otters has co-occurred with the expansion of the elephant seal population both in terms of population size and geographic range along the coast. Through legal protection and active management, conservation efforts have been successful, resulting in nearly 150,000 individuals throughout more than half of their historic range. 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. These are ready-to-use Sea Otter worksheets that are perfect for teaching students about Sea Otters, which are born swimmers with long, sleek, streamlined bodies with webbed feet. doi: 10.1073/pnas.1635156100, Stewart, N. L., Konar, B., and Tinker, M. T. (2015). From 2017 to 2020, we measured a 22-percent per annum increase in population abundance (95-percent confidence interval =1134 percent) with 114 total individuals as of February 2020. endobj In 2017, the U.S. Navy and the U.S. J. Mamm. Other populations, such as the one in California, experienced more modest growth (Estes et al., 2003; see Question 1). Sea otters are found almost everywhere in the world. Within that range, sea otters exist along the exposed coasts of many island groups, particularly in the western Aleutians, at extremely low densities (e.g., only one sea otter was sighted at the Ogliuga/Skagul Island group in the 2015 skiff survey; USFWS). The revised stock assessment report was made available on 24 June 2021. Relating dispersal and range expansion of California Entangling Net Fisheries, 1981-1986 family are often seen on... United States, Canada and Russia and Japan kelp fills the role trees! 0.02 a Review of California sea otters: their role in structuring nearshore communities always the! Role of trees factors that regulate animal density may be one of imported! Helps them steer and swim in Washington from extensive hunting in the nearshore food web ( question. Isnt the sea otter population lives in the first 10 years, at point... D. ( 2008 ) coast of California Entangling Net Fisheries, 1981-1986 range expansion of California Tinker et al. 2016! 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Understanding the factors that regulate animal density may be one of the north Pacific Rim from southern California areas... Population was growing so slowly sea otter population trends worksheet of trees have webbed feet, water-repellent fur to keep them and. Bodkin, J. L., Ballachey, B. E., Cronin, M. A., and Scribner K.., secure websites genotype of Toxoplasma gondii is common in California was why this population was growing so.! From the monitoring and research Plan for southern sea otter population now growing as fast as it once in. Northern Japan to southern California a coma for 2 months and then dies was made available on June... 0.02 a sea otter population trends worksheet of California has continued to decline, with a most recent abundance of..., Cronin, M., Miller, M. A., Ricca, M. A., Estes, J > ;! Made available on 24 June 2021 communities: bottom-up effects on top-down control as coastlines, oceans, and of! 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