Their hind feet are webbed to aid in swimming, and their front toes are short and stiff. Since 1993, we have conducted aerial surveys of sea . /SA true 1 2 . However, as sea otter populations recover, a range-wide approach to their conservation and management is needed, something that does not currently exist. 30 mil 20 mil 6 mil 0 5 10 15 20 25 30 Years. Resource Competition, Space Use and Forage Ecology of Sea Otters, Enhydra lutris, in Southern Southeast Alaska. 1, A to C).Eelgrass meadows can consist of clonal perennial plants, which propagate vegetatively through rhizomes; sexually reproducing annual plants, which produce flowers and seeds; or a combination of . For southern sea otters to be considered for removal from threatened . doi: 10.2307/1940749, Laidre, K. L., Estes, J. Sea otter populations in the North Pacific were decimated by the fur trade of the 18th and 19th century, and continue to recover and re-occupy historical habitat. Currently, it appears that shark predation is an important factor limiting range expansion, particularly in the northern end of the range. Also, no sea otters were ever observed foraging in these areas, probably due to the lack of inverte- brates (author's pers. Important areas of future research include predicting sea otter range expansion with respect to the distribution of net and trap fisheries, assessing actual levels of incidental take in these fisheries, and innovating gear modifications that reduce or prevent the potential for incidental take while maximizing catch of target species. This preview shows page 1 - 3 out of 7 pages. This fact is particularly note-worthy because of the unanticipated decline of sea otters in the original source population in the Aleutian Islands. doi: 10.1111/j.1365-2656.2006.01117.x, Lapiedra, O., Schoener, T. W., Leal, M., Losos, J. The maritime fur trade in the late 18th and 19th centuries decimated and fragmented the sea otter population that once extended around the North Pacific Rim from northern Japan to central Baja California in Mexico. Mother sea otters nurse their pup for about eight months. Ecology 73, 413428. Trend lines for the mainland (left vertical axis) are shown as "3-year running averages" of independents (dashed green line) and total otters (solid blue line). 45, 322375. For example, the western Aleutian MU was derived from two remnant colonies and includes island groups separated by up to 100 km with few, widely dispersed hotspots making genetic exchange unlikely. endobj doi: 10.7589/0090-3558-39.3.495, Krkosek, M., Lauzon-Guay, J. S., and Lewis, M. A. doi: 10.1002/ecs2.1604, Lensink, C. J. With no more otters to eat them, the sea urchins, which eat the Do trophic cascades affect the storage and flux of atmospheric carbon? PLoS Negl. As populations have grown, emigration (initially pioneering males followed by young females) into unoccupied areas reduces the number of sea otters in areas currently occupied (Garshelis et al., 1984). Sea otters likely have been the top-down force structuring clam populations along the KATM coast as clams constitute 63% of the otters diet. Finally, with increasing emphasis on the recovery of endangered species and ecosystem function, we need robust methods to quantify the less tangible benefits of recovery to society, including non-use value. Tinker, M. T., Doak, D. F., Estes, J. Continuation of these surveys and further development and refinement of spatial modeling methods to predict (a) the trajectory of range expansion in a region, (b) the rate of range expansion, and (c) the time frame to various population densities within a region could assist fishery managers in these efforts. (2002). 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: 10.1126/science.185.4156.1058, Estes, J. How can you back up. 2020-1115. ) However, gear interactions are difficult to detect in the field, either because observer programs do not exist for the relevant fisheries or because they are impractical to implement at levels of coverage that would yield meaningful results. In addition, the Commission noted the need to update the southern sea otter stock assessment report more frequently. A., Underwood, K. E., and Karmann, M. J. Sea otters are adorable and fascinating little mammals who live most of their lives in water, rarely ever going on land. 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. Trends in Sea Otter Population Abundance in Western Prince William Sound, Alaska: Progress Toward Recovery Following the 1989 Exxon Valdez Oil Spill . Reproduction, preweaning survival, and survival of adult sea otters at Kodiak Island, Alaska. xYkE@i`fj|DIl0sozu3m>N'\Wl\?nn&g;6`vWKMv;s9c7Y[3jcGMgVk5OUmPW5:2ayQ6WN[l Contemporary abalone and oyster mariculture, when conducted using suitable methods, appear to be able to coexist with sea otters. Demographically and ecologically, sea otter populations operate at smaller spatial scales than currently recognized by management agencies (i.e., at the level of subspecies and stock designations that currently span 1,000s of km). Why isnt the sea otter population now growing as fast as it once was in Washington? -;I%bo[Qg. 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. Calif. A. Kolb 156 extinction. Translocations would decrease the time required for sea otters to reoccupy their entire historical range and to restore nearshore community structure and biodiversity in areas where they are currently absent. The population has grown by about 10 percent per year over the past decade and contained about 100 otters in 2019. the southern sea otter Who helps control the sea urchin population? 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. Boat-based Population Surveys of Sea Otters (Enhyda lutris) in Prince William Sound, Alaska, following the &on Vddez Oil Spill Marine Mammal Study 6-6 Final Report -: Marine Mammal Study 6 ("6), titled Assessment of the Magnitude, Extent and Duration of Oil Spill Impacts on Sea Otter Popkztiom in Alaska, was initiated in 1989 as part of the Natural Resource Damage Assessment (NRDA). 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), 1941. The However, since the early 1990s, the Aleutian sea otter population has declined by more the 90%, likely because of killer whale predation (Estes et al., 1998; Doroff et al., 2003; Springer et al., 2003; Williams et al., 2004; Estes et al., 2005). Current (purple) and historic (yellow) sea otter range. MATERIAL AND METHODS Sea otter population changes. Estimating recreation and existence values of sea otter expansion in California using benefit transfer. Mussel Bed Sampling: Standard Operating Procedure, v. 1.2, Southwest Alaska Network. 72, 2236. Built with all over the world Copyright 19992023This site uses cookies to improve your experience. 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). A total of 139 wild sea otters were translocated. 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). (2003). 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). Despite the translocation having been declared a failure, the population on San Nicolas Island continues to increase. Activity budgets derived from time-depth recorders in a diving mammal. These project-based exercises also introduce some basic concepts of entrepreneurial business. Over the past 45 years, the sea otter population has experienced a 50% decline. Drivers of ecosystem productivity, which may dictate the sustainability of commercial bivalve fisheries as well as the carrying capacity of sea otters, should be addressed. Long, sensitive whiskers help the sea otter find prey in dark or murky water, and when underwater, their nostrils and ears close. That is, localized harvests limited sea otter impacts on local subsistence shellfish resources while not having a significant impact on the range-wide sea otter population. SOP for Monitoring Intertidal Bivalves on Mixed-Sediment Beaches - Version 2.0: Southwest Alaska Inventory and Monitoring Network. History and status of translocated sea otter populations in North America. 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. Look for historical information that might make your narrative more interesting. Why do you find those questions interesting? 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. Species Res. These worksheets have been specifically designed for use with any international curriculum. These factors should be quantified, assigned value and incorporated in policy decisions. 4 0 obj Mar. U.S.A. 106, 22422247. At some point, a population may approach an equilibrium density or carrying capacity, although it is not necessarily stable and may fluctuate inter-annually, decadally or over longer time scales depending on other factors (e.g., disease, predation). doi: 10.1111/mms.12261, Traiger, S. B., Konar, B., Doroff, A., and McCaslin, L. (2016). Despite these successful translocations, 4,000 linear km of historically occupied habitat remains unoccupied (Figure 2). New technology is needed to overcome these tagging limitations. 2), (2) the extent to which current density varies among locations, . A., and Jameson, R. J. To minimize the potential for disturbance and harm to sea otters, people sharing sea otter habitat should: New technology useful in documenting sea otter dispersal along with genetic analyses on microgeographic scales are needed to understand historical and contemporary gene flow, especially in populations where predation may have selected against dispersal behavior. 4 0 obj However, it is likely that subpopulations within MUs are functionally independent as well. Soc. LC and LN wrote Question 6. Open-File Report No use, distribution or reproduction is permitted which does not comply with these terms. J. %PDF-1.7 (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. doi: 10.1016/B978-0-12-801402-8.00006-8, Monson, D. H., and DeGange, A. R. (1995). In the first 10 years, at what point did carrying capacity appear to be? 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. The publication, as well as. The data collected by Dr. Estes are shown. %PDF-1.4 Interior Department Fish and Wildlife Service, Vol. *Correspondence: Randall W. Davis, davisr@tamug.edu, Future Directions in Research on Marine Megafauna, View all While Chads et al. Trends in southern sea otter abundance based on 3-year running averages of raw survey counts. For San Nicolas Island (right vertical axis, note scale difference) the trend line (lowest line, in red) represents the annual high counts. Estes, J. Mar. 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 . Between 1938 and 2005 the population of southern sea otters off California's coast increased from about 300 to 2,600. Detecting and inferring cause of change in an Alaska nearshore marine ecosystem. Under their forearms are baggy pockets used to store food and sometimes stones which they use as tools. As a keystone predator, sea otters have also been found to exert strong effects on food web structure and dynamics, and their recovery to impaired ecosystems may have important implications for resiliency of nearshore marine ecosystems to emerging threats such as climate change and infectious diseases. But population recovery has been . Click the button below to get instant access to these worksheets for use in the classroom or at a home. Sea otters and kelp forests in Alaska generality and variation in a community ecological paradigm. In addition, wolves (Canis lupus) are suspected to take live sea otters both on the Alaska Peninsula and near Glacier Bay in Alaska. Managing at smaller scales may not change substantially the cost and logistical challenges of acquiring appropriate data if, for example, research focuses on collecting information on larger areas (e.g., across the western Aleutian chain as is often the case) but simply puts an emphasis on analyzing information at finer spatial scales. KidsKonnect uses a secure SSL connection to encrypt your data and we only work with trusted payment processors Stripe and PayPal. Thus, the California population, even at its maximum growth rate, never had the potential to expand as fast as populations in more complex habitats. WERC collaborates with other research scientists to conduct annual population surveys of the southern sea otter -- a federally listed threatened species. Clim. Ecology 99, 524535. doi: 10.1111/j.2006.0030-1299.14443.x, Heithaus, M. R., Frid, A., Wirsing, A. J., and Worm, B. Population expansion occurred initially through protection from hunting and later through reintroductions with varying degrees of success. Markel, R. W., and Shurin, J. In addition, the risk of oil spills remains an ongoing concern. Although the data from these earlier surveys provide reasonably detailed assessments of (1) trends in sea otter abundance and distribution at several index islands (Fig. doi: 10.2307/41811831, Wilson, D. E., Bogan, M. A., Brownell, R. L. Jr., Burdin, A. M., and Maminov, M. K. (1991). 32, 9971006. is a free, award-winning online publication dedicated to providing age-appropriate science news to learners, parents and educators. Both perspectives will benefit from a multi-faceted approach to monitoring not only sea otters, but the nearshore ecosystems they occupy. 18. For many years, the central question driving research in California was why this population was growing so slowly. (1947). Unlike other marine mammals that tolerate external attachment of instruments to the skin or hair using adhesives, sea otters rely on the thermal insulation of their fur, which adhesives or other forms of external attachment can compromise. << Pre-maritime fur trade management of sea otter abundance and coastal marine ecosystems suggests some form of population monitoring and management by indigenous peoples of North America to preserve shellfish resources (Simenstad et al., 1978; Salomon et al., 2015). Conserv. Biol. Annually, we estimated abundance for all species within four regions spread across 1,000 km in the Gulf of Alaska. During the maritime fur trade, sea otters were exterminated throughout much of their range not by commercial harvest per se, but by serial harvests that extirpated animals from one area to the next (Bodkin, 2015). These results can be useful to the planning of future monitoring and research of sea otters at San Nicolas Island. Except for the Oregon and Pribilof translocations, which failed for unknown reasons, these efforts were successful and resulted in growing sea otter populations today (Jameson et al., 1982). The sea otter is the largest otter, reaching 100-160 cm (40-65 inches) long and weighing 16-40 kg (35-90 pounds) when fully grown. A .gov website belongs to an official government organization in the United States. SL wrote Question 5. 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). Science 360, 10171020. Today, almost 90% of the sea otter population lives in the coastal waters of. The population has continued to decline, with a most recent abundance estimate of 2,962 otters in 2019. Int. 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. 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. Fish and Wildlife Service (2013). An official website of the United States government. Although the FWS declared the translocation a failure, it is quite possible that otter numbers at San Nicolas will continue to grow. We will develop an integrative modeling approach that can be used to combine a broad range of data types including behavior, life history, demography, bio-medical, physiology, pathology, parasitology and epidemiology, in order to arrive at a process-based understanding of the factors affecting sea otter populations, and then use this model to provide resource managers with projections of population dynamics and viability under alternative management scenarios, and/or in response to anticipated environmental change. >> Monogr. 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. Today, southern sea otters occupy approximately 13% of their historic range; their current distribution extends along the central California coast from Monterey Bay to Point Conception. Ecol. Biol. 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: 10.1016/j.mambio.2012.03.002, Yeates, L. C., Williams, T. M., and Fink, T. L. (2007). Sea otters are the only marine mammal that does not have blubber to keep them warm. Look in the library and on the Internet to learn what animals live in a kelp forest. Population expansion occurred initially through protection from hunting and later through reintroductions varying... 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