However, little evidence exists of population monitoring during the commercial fur trade era beyond harvest records (Lensink, 1960). Open-File Report As a result, the prey of the urchins - the kelp - vastly decreased in density because there were more urchins eating more kelp. The mother will hold her pup on her chest to nurse it and gradually teach it to swim, forage/hunt/retrieve food. Explain. How many burgers do you think you would eat in a day, if that was your only food? Fish and Wildlife Service. These results can be useful to the planning of future monitoring and research of sea otters at San Nicolas Island. At the same time, sea otters have helped to restore the ecological functioning of degraded coastal ecosystems by initiating trophic cascades in kelp forests (Estes and Palmisano, 1974; Estes and Duggins, 1995; Watson and Estes, 2011) and estuaries (Hughes et al., 2013), thereby providing valuable ecosystem services by means of these indirect effects. Monson, D. H., and Bowen, L. (2015). Society for Science & the Public 20002023. Ecol. The data collected by Dr. Estes are shown. Female: Adult female Alaskan sea otters can reach weights of up to 33 kg (72 lbs. doi: 10.1016/B978-0-12-801402-8.00011-1. B., and Kolbe, J. J. Front. 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. Nat. Sea otters are one of the smallest marine mammals in the world, yet they are the largest member of the weasel family. endobj -;I%bo[Qg. 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. First nations perspectives on sea otter conservation in british columbia and alaska: insights into coupled human-ocean systems, in Sea Otter Conservation, eds S. E. Larson, J. L. Bodkin, and G. R. VanBlaricom (London: Elsevier Academic Press), 301331. J. Mammal. They have webbed hind legs, which look like flippers. Express the amount as a multiple of the imported population and as a percentage. << The Sea Otter (Enhydra lutris): Behavior, Ecology and Natural History. /Width 500 Interior Department Fish and Wildlife Service, Vol. Effects of Sea Otter Colonization on Soft-Sediment Intertidal Prey Assemblages in Glacier Bay, Alaska. doi: 10.1016/j.tree.2008.01.003. In the presence of sea otters, an important natural predator, abalone populations cannot recover to the densities and distribution that characterized the era when sea otters were ecologically extinct. Clam gardens are evidence that aboriginal peoples in British Columbia in the past enhanced intertidal clam production by modifying and cultivating sections of beaches and may have excluded sea otters from these areas (Groesbeck et al., 2014). Killer whale predation on sea otters linking oceanic and nearshore ecosystems. Mothers care for their young while floating on their backs. 50, 626637. When otters disappear, the urchin population explodes and quickly "deforests" the . 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. Where would you go? Because demand for sea otter artifacts is small, the number of animals killed yearly is modest but increasing [currently averaging more than 1,000 per year in Alaska (USFWS, Anchorage, AK, United States)]. However, in the 1700s and. Obtaining this information, especially in more remote areas of the sea otters range, will not be easy and will require coordinated research over decades (see Question 3). Conservation in Practice, in Sea Otter Conservation, eds S. E. Larson, J. L. Bodkin, and G. R. VanBlaricom (London: Elsevier Academic Press), 369389. The main threat to sea otters used to be hunting by native people who used their meat as food and their fur for clothing. Deep-Sea Res. 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). Esslinger, G. G., and Bodkin, J. L. (2009). Not ready to purchase a subscription? Reproduction, preweaning survival, and survival of adult sea otters at Kodiak Island, Alaska. With no more otters to eat them, the sea urchins, which eat the History and status of sea otters, Enhydra lutris along the coast of Hokkaido, Japan. Ecol. Dis. 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. 11, 17791790. (1960). Predation can also force sea otters into refugia that are less accessible to predators, thereby reducing available habitat and secondarily increasing competition for food in safe areas (Heithaus and Dill, 2006; Heithaus et al., 2008; Wirsing et al., 2008; Willems and Hill, 2009). We attempt to assign a cause to observed changes by contrasting top-down (sea otter foraging efficiency and prey abundance) and bottom-up (recruitment, growth rates and environmental metrics such as temperature) processes among the four regions and the scale at which changes occur (e.g., similar changes across all areas vs. changes observed asynchronously among regions). doi: 10.1038/nclimate1944, Atwood, T. B., Connolly, R. M., Ritchie, E. G., Lovelock, C. E., Heithaus, M. R., Hays, G. C., et al. Documented effects of sea otter reoccupation on marine communities include: (1) the expansion of kelp forests by reducing sea urchin populations (Estes and Palmisano, 1974; Estes and Duggins, 1995; Watson and Estes, 2011); (2) the creation of habitat for kelp settlement through disturbance (Kvitek et al., 1992; Weitzman, 2013; Traiger et al., 2016), (3) changes to epifaunal and infaunal species densities and size distributions (Singh et al., 2013; Weitzman, 2013) and (4) a reduction in commercially valuable invertebrates (Estes and VanBlaricom, 1985; Wendell et al., 1986b; Wendell, 1994; Watson and Smith, 1996; Larson et al., 2013; Hoyt, 2015). Population reconstructions that (a) excluded natural immigration and surrogate-releases, (b) excluded releases but . 17, 632647. (2017). 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. Predator-specific landscapes of fear and resource distribution: effects on spatial range use. However, genetic data to assess questions of spatial structuring are limited. Ecosphere 7:e01489. The FWS says that the sea otter population would have to reach about 8,400 animals Although sea otters are often referred to as an upper trophic level predator, they are not always at the apex. Population Dynamics and Foraging Ecology of Northern Sea Otters (Enhydra lutr. 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. Based on the target harvest rate (kg/yr) and growth rate. The GIS shapefile Range extent of southern sea otters 2019.shp is a simple polyline representing the geographic distribution of the southern sea otter (Enhydra lutris nereis) in mainland California, based on data collected during the spring 2019 range-wide census. They also rest/sleep wrapped in long strands of kelp which acts like an anchor keeping them close to their group and food source. Acad. Fish and Wildlife Service, 2013). J. Wildl. Instruments attached to the hind flippers are susceptible to removal or destruction by the animal and must be extremely small and lightweight to avoid tearing the flippers webbing. Link will appear as Sea Otter Facts & Worksheets: https://kidskonnect.com - KidsKonnect, August 5, 2018. doi: 10.2307/1940749, Laidre, K. L., Estes, J. A second method to monitor abundance is to correct for sighting bias of animals not detected and areas not surveyed. Considering (1) that the 2000 The population has continued to decline, with a most recent abundance estimate of 2,962 otters in 2019. doi: 10.2307/2937159. Causes of mortality in California sea otters during periods of population growth and decline. Mamm. doi: 10.2307/1379491, Simenstad, C. A., Estes, J. w !1AQaq"2B #3Rbr Gestation is 4 to 5 months, resulting in a single pup that weighs 3 5 lb (1.5 2.5 kgs). resources and objectives, sea otter population trends, and the power and resolution of the survey data to document changes in abundance. (USGS). Econ. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). Estes, J. Monitoring efforts have varied in frequency and type across years. USGS California Sea Otter Surveys and Research page, International Union for Conservation of Nature (IUCN) Sea Otter page, Marine Mammal Commission Sea Otter Reintroduction Fact Sheet, Marine Mammal Commission: An Independent Agency of the U.S. Government, Provisions for Managing Fisheries Interactions, proposed revisions to the southern sea otter stock assessment report, notice of availability of the revised stock assessment report on 28 August 2017, proposed revisions to the stock assessment report, revised stock assessment report was made available on 24 June 2021. The USGS range-wide sea otter census has been undertaken each year since 1982, using consistent methodology involving both ground-based and aerial-based counts. 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. More information 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. If you reference any of the content on this page on your own website, please use the code below to cite this page as the original source. Female sea otters become sexually mature at around four years of age, and males at around five. Historic and contemporary status of sea otters in the North Pacific, in Sea Otter Conservation, eds S. E. Larson, J. L. Bodkin, and G. R. VanBlaricom (London: Elsevier), 4361. ) or https:// means youve safely connected to the .gov website. From a conservation genetics perspective, it is interesting to note that genetic diversity is highest in translocated populations derived from two source populations (Larson et al., 2002b). Webinar for K-12 educators: "Sea Otters and People.". Fish Game 72, 197212. JB wrote Question 4. Carswell, L. P., Speckman, S. G., and Gill, V. A. An increased emphasis should be placed on quantifying the beneficial socioeconomic effects of sea otters (e.g., ecotourism) and sea otter-induced trophic cascades in kelp and seagrass habitats (e.g., benefits to finfish fisheries resulting from increases in finfish populations, increases in atmospheric carbon sequestration, and reduced shoreline erosion). College Park, MD: National Archives and Records Administration, 75266. 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. (2009). The spring census provides the primary basis for gauging population trends by State and Federal management agencies. 147, 8797. Comp. The total economic value of threatened, endangered and rare species: an updated meta-analysis. (2013). Range expansion predictions based on dispersal distance or reaction-diffusion models had mixed success but generally did not provide definitive biological context for the mechanisms driving population expansion (Lubina and Levin, 1988; Krkosek et al., 2007). Zool. Ph.D. thesis, University of Alaska, Fairbanks. Managers may be served better by defining populations at smaller spatial scales even within the Southwest Alaskan DPSs five MUs. For the time being, Elkhorn Slough is our best example in California of sea otters using estuarine habitats which have different environmental factors than say, kelp forests and other habitats along the coast. (2011). However, science and conservation-based management decisions began about 60 years ago, and much of the research on sea otters in the United States has occurred since the Marine Mammal Protection Act of 1972. Click the Edit button above to get started. Acad. 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. 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). Due to their thick, soft pelts, sea otters were hunted extensively until an international ban was enforced to prevent their extinction. C i" Reston, VA. Estes, J. As sea otters reoccupy an area, populations of epibenthic prey such as sea urchins, crabs and abalone generally decline first followed by infaunal species such as large bivalves, depending on habitat (Kvitek and Oliver, 1992; Kvitek et al., 1993). Explain. Sea urchins prey on kelp. By helping to maintain viable sea urchin populations, the sea otters are also allowing enough kelp to grow and act as a habitat for other organisms.Suppose that a bacterial infection swept across a sea otter population and killed most sea otters before they could reproduce. To find out more, see our cookie policy. See how sea otters maintain the balance of kelp-forest ecosystems by consuming sea urchins (1988). 56, 701703. Following almost two centuries of commercial hunting, sea otter populations were severely reduced; surviving southern sea otters consisted of a small colony of otters along the remote Big Sur coast of central California. This manuscript has been approved for publication consistent with USGS Fundamental Science Practices (http://pubs.usgs.gov/circ/1367/). 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. Write a letter explaining why an organization should give you money for your work. PLoS One 11:e0150547. What percentage of your weight would those burgers represent. Kelp and rivers subsidize rocky intertidal communities in the Pacific Northwest (USA). doi: 10.1038/srep33912. /Subtype /Image 32 percent of recovered carcasses were of adult and subadult femalespotential mothersan increase from pre-2008 figures of 27 percent. One is through the macrophytes (kelps, seaweeds and sea grasses) that provide a stable source of productivity. The draft report identified the potential for sea otters to become trapped in gear used to catch crab, lobster, and finfish. The population never grew as expected and in 2012,the FWS declared the translocation a failure. You will, 1 out of 1 people found this document helpful, Name: _________________________________________________________, the four graphs located on the last two pages of this document. International legal protection and translocations in the 20th century have enabled sea otters to recover and reoccupy historical habitats with varying levels of success. 34, 275284. More typical are counts made from skiffs, larger vessels or aircraft in which detection probability is reduced relative to shore-based counts (however, see Cortez et al., 2016). Conserv. 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. Some of these instruments exist, but they require refinement and field-testing on sea otters before their potential use can be assessed. .0.50 0 20 40 60 80 100 Time, days A-55793 . Group of answer choices True False Flag question: Question 2 Question 22.5, Cory watches as her sister Amanda breaks into a parking meter across the street and starts scooping changeinto her purse. Kreuder, C., Miller, M. A., Jessup, D. A., Lowenstine, L. J., Harris, M. D., Ames, J. 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. Otters eat urchins, and urchins eat kelp. The sea otter spends most of its time in the water but, in some locations, comes ashore to sleep or rest. 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. Animal populations are limited by density-dependent and density-independent factors, many of which are known for sea otters, although the importance of individual factors varies. 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! 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). In 2017, the U.S. Navy and the U.S. Figures of Pages from the Monitoring and Research Plan for Southern Sea Otter Military Readiness Area. A., Tinker, M. T., Burn, D. M., and Evans, T. J. They spend around 40% of their time hunting and eating and eat about 25% of their body weight every day. 62, 26482658. 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. Mamm. (1978). Specifically, open water crossings that may have been an insignificant barrier to dispersal before the killer whale-driven decline may now prove an insurmountable barrier for future generations of sea otters, resulting in a significant reduction in gene flow between islands and eventually additional losses of genetic heterozygosity. EXAMPLES: humans, sea otters, sharks population group of individuals of the same species that live in the same area. Evaluating potential conservation conflicts between two listed species: sea otters and black abalone. 1982; Jameson et al. doi: 10.1371/journal.pntd.0002852, Watson, J., and Estes, J. 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. Specifically, all extant sea otter populations have low genetic variability because of the population bottlenecks created by the maritime fur harvest (Larson et al., 2002b, 2015). Monitoring dynamic spatio-temporal ecological processes optimally. These intertidal sites span a range of habitats, from sheltered rocky areas to mussel beds to protected mixed-sediment beaches (Dean and Bodkin, 2011; Bodkin et al., 2016; Weitzman et al., 2017). Lensink, C. J. 3, BIOL111_Lesson_5_-_Homeostasis_Population_Graphs_CC, Dominic_Arnold_-_Homeostasis_Population_Graphs_CC, Lab 1 - Medication Levels in the Bloodstream.docx, Copy of English 12B Week 5 Guided notes (days 1-2).pdf, CHM 204 Structural Determination Practice Key, The stream or heavy setting of a spray bottle will reduce the risk of dispersing, ELAD 7003 Parental Involvment Narrative.docx, of angular momentum is used H 1 H 2 I O 1 m v 1 d I O 2 m v 2 d 1767 The, Compare Johnstone v State Bar of California 1966 64 Cal2d 153 155 156 49 CalRptr, Wk 5 - Transitional Care Application.docx, Copy of 2.04 Lending Investments and their associated Risk_Return.pdf, Carol shoots her father Carl with malice aforethought. 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