5 0 obj Washington, DC: U.S. Adult males will establish territories within these areas and vigorously defend them, thereby limiting the number of males in an area (Garshelis et al., 1984). doi: 10.3354/meps08138, Tarjan, L. M., and Tinker, M. T. (2016). Science 185, 10581060. Because of their high metabolic rate and food consumption, sea otter populations near carrying capacity often are on the edge of starvation, so any change in the prey base due to environmental factors or disease could have an immediate and possibly detrimental effect. (1983). J. Anim. Mar. Trends Ecol. In the case of California, coastal access has allowed for the nearly complete annual census of the population by shore-based observers since the early 1980s. >> B., and Kolbe, J. J. The minimal population estimate was 8,742 sea otters in 2000. The sea otter population in Southeast Alaska has grown extensively since the translocation of just over 400 sea otters to 6 locations in the late 1960s. Research is needed to quantify the strength and persistence of sea otters effects on these and other species targeted by finfish fisheries, to identify the relevant timescale over which changes may be anticipated after sea otters recolonize and area, and to link these changes to fisheries production. Fish and Wildlife Service. 6) "Keep Sea Otters in the Picture" poster (Sea Otter History, Web of Life, Sea . is a free, award-winning online publication dedicated to providing age-appropriate science news to learners, parents and educators. Share sensitive information only on official, secure websites. Evol. However, available information is often inadequate for managers to conduct meaningful analyses or to anticipate and mitigate conflicts before they occur. (2015). Plot of southern sea otter population trends along the mainland coast of California and at San Nicolas Island over the period 1990-2013. A., and Palmisano, J. F. (1974). Environ. In the following, we recommend avenues for future research on sea otters in relation to fisheries, threatened or endangered species, climate change, ecotourism, and non-market valuation to inform the analyses that guide environmental policy and management. Long, sensitive whiskers help the sea otter find prey in dark or murky water, and when underwater, their nostrils and ears close. Calculated natural population trends for the Amchitka sea otter since 1910. /SA true Evol. The publication, as well as. A., and VanBlaricom, G. R. (1985). The U.S. 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! /ColorSpace /DeviceRGB Incorporating diverse data and realistic complexity into demographic estimation procedures for sea otters. Ideally, the definition should be based on demographics and the dispersal distances of individuals in the population. Monogr. Eventually, remnant and introduced populations increased in abundance and distribution, with some becoming contiguous over spatial scales of thousands of kilometers and comprising tens of thousands of individuals. Development of an altricial mammal at sea I: activity budgets of female sea otters and their pups in Simpson Bay. 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). A., and Kenyon, K. W. (1978). 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). magazine, are published by the Society for Science, a nonprofit 501(c)(3) membership organization dedicated to public engagement in scientific research and education. Plot of southern sea otter population trends along the mainland coast of California and at San Nicolas Island over the period 19902013. For many years, the central question driving research in California was why this population was growing so slowly. Elkhorn Slough National Estuarine Research Reserve, Biologist & Southwest Region Dive Safety Officer, 12201 Sunrise Valley Drive Reston, VA 20192, Western Ecological Research Center (WERC). Understanding the factors that regulate animal density may be one of the most challenging and expensive ecological questions. A total of 139 wild sea otters were translocated. /CreationDate (D:20220815072648+03'00') Econ. Image by R. Davis taken under the authority of United States Fish and Wildlife Service LOC MA-043219. Life history plasticity and population regulation in sea otters. Technical Report No. Changes in Alaskan soft-bottom prey communities along a gradient in sea otter predation. It inhabits coastal waters from the Kuril Islands to the Aleutian Islands southward to the coast of California. This abundant population lasted until the early 1700s when the hunting of otters for their pelts began to popularize. J. Trop. (2018). 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. The Oregon sea otter population model has been developed as a user-friendly interface for community members and managers to explore possible sea otter recovery patterns after introduction. Southern sea otters, also known as California sea otters, live in the waters along the central California coastline. The 2017 count declined somewhat, to 3,186 otters, but still exceeded the potential delisting threshold for a second straight year. doi: 10.2307/41811831, Wilson, D. E., Bogan, M. A., Brownell, R. L. Jr., Burdin, A. M., and Maminov, M. K. (1991). A., and Duggins, D.O. 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. Panel A shows sea otter abundance around four different islands from 1972 to 1997 . However, this population has persisted, continues to grow and now numbers 80 animals (Tinker and Hatfield, 2017). Mar. Females with pups will occupy areas that provide important resources such as food and protection from wind and waves. 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. Clim. Sea otters may homogenize mussel-beds and reduce habitat provisioning in a rocky intertidal ecosystem. Following their near extirpation, there was little effort to monitor them because remnant populations were small, remote and in some cases unknown. 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. Conserv. 39, 15531571. The History and Status of Sea Otters in Alaska. 81, 215239. (2003). doi: 10.1890/10-0262.1. Females move freely among these territories, but any female within a territory will be investigated for sexual receptivity. Monitoring efforts have varied in frequency and type across years. Ecol. doi: 10.3354/esr00327, Hattori, K., Kawabe, I., Mizuno, A. W., and Ohtaishi, N. (2005). If you ate 25 percent of your body weight daily, as otters do, how many quarter-pound hamburgers would you eat every day? Students should have prior knowledge of food chains, food webs, and keystone species to successfully complete the activity.As students read the news article, they identify predator-prey relationships within the ecosystem and analyze population trends as well as the root cause of the ecosystem collapse. A. They dive down and forage on the seafloor for food, using rocks to dislodge prey and open shells. Sea otters are the smallest fully marine mammal in the world: Males range in length between 3.9-4.9 feet, while females range between 3.3-4.6 feet. Contemporary abalone and oyster mariculture, when conducted using suitable methods, appear to be able to coexist with sea otters. Currently, radio telemeters are implanted in the abdominal cavity, which precludes the use of satellite-linked devises because of antenna limitations. 71, 20342044. J. Mamm. Sci. (2004). College Park, MD: National Archives and Records Administration, 75266. 111 , .. . Sci. J. KidsKonnect uses a secure SSL connection to encrypt your data and we only work with trusted payment processors Stripe and PayPal. Sea otters are susceptible to entanglement and drowning in gill nets (Wendell et al., 1986a; Herrick and Hanan, 1988; Forney et al., 2001) and to entrapment and drowning in finfish, lobster, and Dungeness crab traps (Hatfield et al., 2011). Lensink, C. J. Markel, R. W., and Shurin, J. A. Open-File Report Fish and Wildlife Service, 2013). doi: 10.1890/1051-0761(2006)016[2293:IDDARC]2.0.CO;2, Tinker, M. T., and Hatfield, B. Diet and foraging behavior of sea otters in southeast Alaska. The goal of this article is to identify and address some of the key questions and challenges for future research and management that will contribute to the full recovery of sea otters to pre-exploitation levels, reoccupation of their historical range, and restoration of nearshore ecosystems. 131, 526543. MATERIAL AND METHODS Sea otter population changes. 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). Recommendations for future research and management that will allow full, pre-exploitation recovery and restoration of nearshore ecosystems should focus on at least seven key challenges. The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. (2015). Mothers care for their young while floating on their backs. A key indicator of recovery of the population is its ability to expand its range along the California Coast. 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. Evidence indicates that commercial shellfish fisheries are unlikely to persist in an area once sea otters have recolonized it. (2001). Status and Trends of Sea Otter Populations in Southeast Alaska, 19692003. A., Kreuder, C., Paradies, D. M., Worcester, K. R., Jessup, D. A., et al. Oecologia 177, 645655. Continued protection and conservation will be required for many decades. 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. Explain. 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. Alaska Natives can hunt sea otters legally but cannot sell unaltered pelts. '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. However, few remained at the island, and many swam 100 km back to the California mainland (Rathbun et al., 2000). An important density-independent factor is primary production, which injects carbon and nutrients into the food web (see Question 3). (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. Monitoring dynamic spatio-temporal ecological processes optimally. Currently, the United States Fish and Wildlife Service identifies the Southwest Alaska sea otter stock as a single Distinct Population Segment (DPS, U.S. 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 research is being led by a partnership of the U.S. Geological Survey, University of California-Santa Cruz, California Department of Fish and Wildlife, the Monterey Bay Aquarium, and the Elkhorn Slough National Estuarine Research Reserve (ESNERR), with assistance from other partners. Dean, T. A., Bodkin, J. L., and Coletti, H. A. Teacher Resources. Experiment: Are fingerprint patterns inherited? A., Ricca, M. A., Miles, A. K., and Forsman, E. D. (2008). 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. Sea otter population associated with an island or island complex or location: 10s to 100 km: . 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. Sherrod, S. K., Estes, J. rents. 73, 88. Sea otters and kelp forests in Alaska generality and variation in a community ecological paradigm. The population decline likely began in the mid-1980s and declined at a rate of 17.5%/year in the 1990s. In addition to abundance, trends, distribution, and forage energy intake across seasons and years, these replicated surveys provide information on the precision of data achieved by quarterly survey effort. Sea otters sleep on the surface of the water, floating on their backs and either holding on to each other or wrapped in strand kelp/giant seaweed to prevent them from floating away from their site. It includes space for writing their answers and drawing a picture. United States. 9, 168181. Future actions to promote the conservation and recovery of the southern sea otter will depend on the results of ongoing research, particularly if needed to respond to human-caused sources of mortality. A, You work for the US Department of Agriculture and you are measuring the change (increase) in biomass of a soybean crop over its growing season (from planting until it's ready to harvest).What have, Given the following information about cows grazing in a field (all terms are GJ/yr/ha): Plant production (Pp) = 85 GJ/yr/ha Ingestion = 65 GJ/yr/ha Assimilation = 35 GJ/yr/ha Respiration = 32, A chef wants to harvest a fancy type of mushroom that grows in the forest behind his house (be careful doing this, as some can be deadly!). 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). Acad. doi: 10.1073/pnas.94.26.14530, Miller, M. A., Gardner, I. +(> Xi~PHa3sX#s-mCR*1rFY$Vz!`:_OV Sea otters live in shallow coastal waters in the northern Pacific Ocean. LC and LN wrote Question 6. 1982, 1986; Bodkin et al. Imagine that you are a marine biologist. Sea otters have forepaws, which can rub, twist, and pull. Management authorities may require population definitions based on political boundaries or other geographic, cultural, or economic justifications (Pennock and Dimmick, 1997). Simultaneously with sea otter monitoring, mixed sediment sites have been sampled for infaunal bivalve biomass. 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. Abalone mariculture occurs beneath the Monterey wharf in California in protective cages and indirectly benefits from the presence of sea otters through enhanced local availability of giant kelp, which is harvested to feed the growing abalone. The data collected by Dr. Estes are shown. History and status of sea otters, Enhydra lutris along the coast of Hokkaido, Japan. C i" 84, 5564. endobj To find out more, see our cookie policy. Species Res. Sci. Herrick, Jr, and Hanan, D. (1988). Do trophic cascades affect the storage and flux of atmospheric carbon? Sea-otters and shellfisheries, in Marine Mammals and Fisheries, eds J. R. Beddington, R. J. H. Beverton, and D. M. Lavigne (London: George Allen & Unwin), 187235. J. Anim. Sea otters now are established (with significant gaps) from northern Japan to southern California. A., and Levin, S. A. Ser. SL wrote Question 5. Our results suggest that the population now exceeds 25,000 sea otters and could eventually grow to 3 times that number, if the current patterns of range expansion and density-dependent growth . 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. In Russia, sea otters have a conservation status that prohibits capture or hunting except by special license for science or display purposes (Nichol, 2015). 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). U.S.A. 94, 1453014535. 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. Satellite tracking using animal-borne transmitters is possible with most marine mammals, but not currently with sea otters. doi: 10.1890/08-2086.1, Menge, B. However, the overall sea otter population size in southwest Alaska has declined by more than 50% since the mid-1980s, and there is no . Activity-time budgets of sea otters in California. Some variation in trends . SOP for Sampling of Intertidal Invertebrates and Algae on Sheltered Rocky Shores - Version 4.6: Southwest Alaska Inventory and Monitoring Network. Oikos 114, 257264. Between the late 1970s and early 1990s, the sea otter population range was limited to the outer coast of Washington between Makah Bay and Destruction The FWS estimated southern sea otter abundance in 2016 was 3,272 individuals, a record high since 1972. sea otter population seemed to be quite abundant until the late 1990s, when sea otters . doi: 10.1242/jeb.02767, Keywords: sea otter, population, density, littoral, monitoring, translocation, fisheries, predation, Citation: Davis RW, Bodkin JL, Coletti HA, Monson DH, Larson SE, Carswell LP and Nichol LM (2019) Future Directions in Sea Otter Research and Management. doi: 10.1890/07-1818.1, PubMed Abstract | CrossRef Full Text | Google Scholar, Arkema, K. K., Guannel, G., Verutes, G., Wood, S. A., Guerry, A., Ruckelshaus, M., et al. 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. This sample is exclusively for KidsKonnect members!To download this worksheet, click the button below to signup for free (it only takes a minute) and you'll be brought right back to this page to start the download! doi: 10.2307/1380163. These results can be useful to the planning of future monitoring and research of sea otters at San Nicolas Island. Predators help protect carbon stocks in blue carbon ecosystems. of food each day. Study 30, 4151. Watson, J. C., and Smith, T. G. (1996). Hunting has been banned, and now poor water quality and lack of quality habitat are the main threat to sea otters. 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). 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