39, 495509. Natl. /Type /ExtGState 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). Acad. KidsKonnect is a growing library of premium quality educational materials, printable worksheets and teaching resources for use in the classroom. B., Ralls, K., and Ames, J. The kelp can flourish, providing habitat for many ocean organisms. <>
147, 8797. A raft usually comprises single-sex sea otters numbering from 10 to over one hundred individuals. /Title () Furthermore, an abundance of urchins (a primary sea otter prey) in habitats where sea otters disappeared (Stewart et al., 2015) and an increase in the body size of sea otters during the decline do not indicate that bottom-up influences are responsible (Laidre et al., 2006; Monson, 2009). California Sea Otter (Enhydra lutris nereis) Census Results Spring 2017: U.S. Geological Survey Data Series 1067. doi: 10.3133/ds1067, Tinker, M. T., Hatfield, B. Killer appetites: Assessing the role of predators in ecological communities. 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). (2009). A. Founded in 2003, Science News Explores is a free, award-winning online publication dedicated to providing age-appropriate science news to learners, parents and educators. 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). B., Staedler, M. M., et al. Sea otters dive underwater or cleverly play dead when they sense danger. The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. Kelp and rivers subsidize rocky intertidal communities in the Pacific Northwest (USA). Biol. Session 6: Sea otter conservation, volume 2 Moderator: Jim Bodkin 10:40am Food and energy intake of managed sea otters David Rosen 10:50am The history of monitoring sea otter recovery and conservation George Esslinger 11am Sea otters, seagrass and saltmarshes: past and present Erin Foster 11:10am What drives sea otter population growth and . The other is through seasonal blooms in phytoplankton that can occur within an area or be transported to nearshore habitats. This abundant population lasted until the early 1700s when the hunting of otters for their pelts began to popularize. A., Kreuder, C., Paradies, D. M., Worcester, K. R., Jessup, D. A., et al. Weitzman, B. P. (2013). The Commission identified a need to establish an observer program with sufficient coverage to obtain reliable information on the rate and circumstances surrounding the entrapment of sea otters in such gear. A .gov website belongs to an official government organization in the Otter meat is nutritious and edible and was a valuable source of food for many people for many years. This site uses cookies to improve your experience. 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). doi: 10.1073/pnas.0806449106. Bull. Fish and Wildlife Service, 2013). Acad. Worksheet completed alongside the hhmi BioInteractive movie: Some Animals Are More Equal than Others: Keystone Species and Trophic Cascades. Ancient clam gardens increased shellfish production: adaptive strategies from the past can inform food security today. Manage. Geographic variation in sea otters, Enhydra lutris. These results can be useful to the planning of future monitoring and research of sea otters at San Nicolas Island. doi: 10.1002/ecs2.1489. This worksheet can be edited by Premium members using the free Google Slides online software. The population decline likely began in the mid-1980s and declined at a rate of 17.5%/year in the 1990s. 13, 219229. Mar. Overview of Alaska sea otter ecology and recent research related to human-sea otter conflicts in Kachemak Bay and Southeast Alaska. A., Doak, D. F., and Springer, A. M. (2004). A. Kolb 156 extinction. (USGS). 70, 14981507. Clim. Disease, parasites and predation were identified as possible factors (Miller et al., 2002, 2004; Kreuder et al., 2003; Conrad et al., 2005a,b, Johnson et al., 2009), but it appeared unlikely that these factors fully explained the populations slow growth. (1986a). Given the contribution of translocations to the conservation of sea otters by increasing the total numbers of sea otters present today, increasing population connectivity, increasing genetic diversity, and restoring coastal marine ecosystems, we suggest additional translocations be considered to facilitate sea otters recolonization of their historical range. doi: 10.1111/eva.12642, Garshelis, D. L., Johnson, A. M., and Garshelis, J. 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. (2004). q"4\$j$\F,p1*'H`q $UU` FH'[TzVe6sQ=^)f}Ak 1.25 2.0 - 1.00 o o x a 0 Otters *, 0 5 Food .5- 0.75 LL. They estimated the impact of killer whales on sea otter populations by comparing trends in population size and survival rates of individually marked otters between two adjacent locations on Adak Island: Clam Lagoon and Kuluk Bay. doi: 10.1073/pnas.1635156100, Stewart, N. L., Konar, B., and Tinker, M. T. (2015). Activity Patterns and Time Budgets of Sea Otters at Amchitka Island, Alaska. Currently, the Alaska sea otter population is divided into three stocks (Gorbics and Bodkin, 2001). In Elkhorn Slough near Moss Landing, California, scientists hope to compile new data to support the recovery of the southern sea otter, a federally threatened species under the Endangered Species Act. Critique of the evolutionarily significant unit as a definition for distinct population segments under the US endangered Species act. Because of their well-documented effects on nearshore communities, broadly monitoring the littoral community along with sea otters provides information on the status of the ecosystem (Coletti et al., 2016). Fish and Wildlife Service (FWS) listed the Southwest Alaska stock as threatened in 2005 and designated critical habitat for the population in 2009. Geological Survey3020 State University Drive EastSacramento, California 95819. Environ. Additional resources (found in trunk) that can be used to supplement reading articles: 1. As remnant populations increased their range and abundance, dedicated counts were made, eventually leading to the first systematic population monitoring (Barabash-Nikiforov, 1947; Lensink, 1962; Kenyon, 1969). 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. /SMask /None>> C.ultimately inconclusive, because it does not incorporate data from sea otter population surveys conducted before 2010. According to the 2021 stock assessment report, the observed decline reflects lower numbers of otters in the northern and southern portion of the mainland range, offset somewhat by continued growth of the central portion of the mainland range and the translocated population at San Nicolas Island. 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). Sci. The importance of marine predators in the provisioning of ecosystem services by coastal plant communities. As sea otter populations have recovered, they have come into contact and sometimes conflict with human activities that developed during the more than 100 years when the sea otter was ecologically extinct as a keystone species in the nearshore (Estes and VanBlaricom, 1985; Wendell et al., 1986b; Wendell, 1994; Watson and Smith, 1996; Larson et al., 2013; Hoyt, 2015). 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. Sci. 30 mil 20 mil 6 mil 0 5 10 15 20 25 30 Years. Examples of this type of strategy include conducting smaller spatial-scale surveys at more frequent intervals (Bodkin, 2015; Coletti et al., 2016), rather than large-scale surveys less frequently, where demographically distinct population trends could become confounding (Esslinger and Bodkin, 2009). 10, 100107. Imagine that you are applying for money to study sea otters. 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. Front. You print it front to back and fold it like a brochure. J. Trop. (2015). Influence of sea otters on soft-bottom prey communities in southeast Alaska. doi: 10.1080/08920750600860282, Lubina, J. 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. Predators help protect carbon stocks in blue carbon ecosystems. 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. Stock structure of sea otters (Enhydra lutris kenyoni) in Alaska. 59, 385401. 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. A., Hatfield, B. 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). Sea otter distribution in California (the mainland range) is . Int. No survey counts occurred during 2020. Variation in their current status, and in the rate and pattern of recovery, provides an opportunity to use the comparative approach to elucidate how various natural and human-caused stressors affect population health and dynamics. Sea otter population declines have also been observed further east in the Kodiak archipelago. Patterns of growth and body condition in sea otters from the Aleutian archipelago before and after the recent population decline. Wendell, F. (1994). From those sites, we may be able to extrapolate throughout the sea otters range. Front. doi: 10.1073/pnas.94.26.14530, Miller, M. A., Gardner, I. The Commission also recommended that, as a precautionary measure, gear modifications to reduce entrapment of sea otters be adopted for crab and lobster traps, similar to those that have been in place for finfish traps since 2002. 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. 13, 13781385. Am. <>
Riedman, M. L., and Estes, J. To understand the complex interaction of factors that influence sea otter density, tracking individual animals and conducting regular censuses at appropriate spatial scales is needed. Imagine that you are on a hunting ship long ago when there were many sea otters. 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? LockA locked padlock Imagine that you are a marine biologist. Conserv. Where would you go? Fish and Wildlife Service. 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. doi: 10.3354/meps082103, Kvitek, R. G., Oliver, J. S., DeGange, A. R., and Anderson, B. S. (1992). Indirect effects and prey behavior mediate interactions between an endangered prey and recovering predator. Sea otter abundance has been stable in the Kenai Fjords National Park (KEFJ) in southcentral Alaska since at least 2002. Census methods produce counts that are biased low, to varying degrees, but may be suitably precise for monitoring trends over time assuming detection is relatively constant. 35, 11551168. J. Wildl. (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. International legal protection and translocations in the 20th century have enabled sea otters to recover and reoccupy historical habitats with varying levels of success. The sea otter is the largest member of the weasel family. Secondly, the few remaining sea otter hotspots have small effective population sizes at risk of additional losses of genetic diversity. They groom by licking their fur, scratching it with their paws, and rubbing themselves against rocks or logs. doi: 10.1034/j.1600-0706.2000.900304.x. Testing the nutritional-limitation, predator-avoidance, and storm-avoidance hypotheses for restricted sea otter habitat use in the Aleutian Islands, Alaska. Despite the translocation having been declared a failure, the population on San Nicolas Island continues to increase. Join 51,000+ happy teachers and students who use our teaching worksheets and resources every day. The mother will hold her pup on her chest to nurse it and gradually teach it to swim, forage/hunt/retrieve food. Ecol. It inhabits coastal waters from the Kuril Islands to the Aleutian Islands southward to the coast of California. The sea otter spends most of its time in the water but, in some locations, comes ashore to sleep or rest. -;I%bo[Qg. Ecology 73, 413428. population at San Nicolas Island, California, has been monitored annually since the translocation of 140 sea otters to the island was completed in 1990. Coastal habitats shield people and property from sea-level rise and storms. He thereafter lingers in a coma for 2 months and then dies. doi: 10.2307/3800973. Bull. Wendell, F. E., Hardy, R. A., Ames, J. Aquat. Can. Both perspectives recognize the important role sea otters play in structuring the shallow, littoral ecosystem, but the perspectives differ in time and space. Initially, remnant populations were small and occupied small ranges, enabling surveys that could be conducted from skiffs with limited personnel and time. Pathogenesis of Streptococcus infantarius subspecies coli isolated from sea otters with infective endocarditis. In addition, the GWA program evaluates various tractable performance metrics for key species such as survival rates, size distributions and diets. Open Fish Sci. Understanding the factors that regulate sea otter density will be challenging and likely require focusing on a few index sites that are representative of the variety of littoral habitats occupied by sea otters around the North Pacific Rim. doi: 10.1016/j.mambio.2012.03.002, Yeates, L. C., Williams, T. M., and Fink, T. L. (2007). Mar. Microsatellite DNA and MtDNA variation in remnant and translocated sea otter (Enhydra lutris) populations. (2006). When otters are present, urchins hide in crevices and snack on kelp scraps. Plot of southern sea otter population trends along the mainland coast of California and at San Nicolas Island over the period 1990-2013. Monitoring efforts have varied in frequency and type across years. Watson, J. C., and Smith, T. G. (1996). Sea otters versus sea stars as major clam predators: evidence from foraging pits and shell litter. 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). B., Harris, M. D., and Ames, J. d7f;?VF+!
8fpbP`T%npZU5Xp{AHa" O1J%t#)fnLMnX8'T%"8%E]!R All rights reserved. Continued protection and conservation will be required for many decades. Tinker, M. T. (2015). Sea otters rely on their fur for insulation, which cannot be compromised by the attachment of external satellite telemeters used with many other marine mammal species. The most recent estimate of sea otter population abundance in Washington was 2,785 individuals (2,632 independents, 153 pups; Jeffries et al. doi: 10.1086/284804. J. 389, 8596. Given that southern sea otters have failed to significantly expand their range over the past two decades and the recent decline in the population trajectory, the Commission also recommended that the FWS make its stock assessment reviews available annually. Washington's current sea otter population Foraging data were collected on a total of 2,675 foraging dives in 167 foraging bouts, and the majority of identified prey on successful dives (n=1,335) were sea urchins (940) followed by snails (240) and crabs (78). (1978). 6, 2840. doi: 10.1016/j.tree.2008.01.003. /CreationDate (D:20220815072648+03'00') This manuscript includes a review of past research and does not include any new data or metadata releases. Females with pups will occupy areas that provide important resources such as food and protection from wind and waves. However, available information is often inadequate for managers to conduct meaningful analyses or to anticipate and mitigate conflicts before they occur. B. The Commission continues to follow closely ongoing research into the status and trends of this population, both for the coastal parent population and the translocated population on San Nicolas Island. Geoduck clam (Panopea abrupta) demographics and mortality rates in the presence of sea otters (Enhydra lutris) and commercial harvesting. 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. The U.S. The Russia, Alaska, and California populations are each designated as subspecies in part for management purposes, although there are some morphological differences (Wilson et al., 1991). << 1 2 . Calculated natural population trends for the Amchitka sea otter since 1910. doi: 10.1016/B978-0-12-801402-8.00011-1. 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). (2007). The risk of eagle predation appears to have had behavioral effects on female sea otters, which tend to forage at night and employ other behaviors indicative of heightened vigilance when accompanied by newborn pups (Gelatt, 1996; Cortez et al., 2016). Sea Otter Population Trends Direction:Complete the Sea Otter Population Graph (Graph #3) and answer the questions below. A new pathogen transmission mechanism in the ocean: the case of sea otter exposure to the land-parasite Toxoplasma gondii. What could be some possible hypotheses for why the kelp population is changing? Can. During the past 60 years, much has been learned about their natural history, physiological adaptations for an aquatic life, and the important role they play in structuring nearshore marine ecosystems. They have thick, glossy, water-repellent fur and enjoy both swimming and floating on their backs. 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. Changes in Alaskan soft-bottom prey communities along a gradient in sea otter predation. An analysis of sea otters and kelp forests. National Oceanic and Atmospheric Administration Technical Memorandum National Marine Fisheries Service NOAA-TM-NMFS-SWFC-108. A Review of California Entangling Net Fisheries, 1981-1986. However, genetic data to assess questions of spatial structuring are limited. doi: 10.1126/science.282.5388.473, Estes, J. Appl. Mar. An unusual genotype of Toxoplasma gondii is common in California sea otters (Enhydra lutris nereis) and is a cause of mortality. t HWv@&Lwa*>jja|tlXCFwdhbF;"ST+\+ In 1911, hunting was prohibited under the terms of an international treaty for the protection of North Pacific fur seals and sea otters signed by the United States, Japan, Great Britain (for Canada), and Russia. Historical ecology of late Holocene sea otters (Enhydra lutris) from northern British Columbia: isotopic and zooarchaeological perspectives. w !1AQaq"2B #3Rbr 32, 309326. Hughes, B. 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. Today, 4,000 km of historically occupied habitat remains unoccupied. Click to download the free sample version, Sea otters are adorable and fascinating little, Average Lifespan in the Wild: 15 -20 years, Average Size: 3 ft 11 in 4 ft 11 in (1.2 1.5 m), Average Weight: 30 100 lb (14 45 kg ), Male sea otters are called boars, females are sows, and newborns are pups, Subspecies Three subspecies of the sea otter are recognized. Diving and foraging energetics of the smallest marine mammal, the sea otter (Enhydra lutris). 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. 57, 199203. 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). The past few decades have demonstrated that sea otter populations can be strongly influenced by the top-down pressure of higher-level predators, and this change in perspective should be acknowledged in management strategies. A., van Vliet, G. B., Williams, T. M., Doak, D. F., Danner, E. M., et al. He's seen the island's population of sea otters soar over the last handful of years . LC and LN wrote Question 6. Sea otter population declines in the Aleutian archipelago. 1986). Female sea otters become sexually mature at around four years of age, and males at around five. %PDF-1.4 Figure 1. Home Facts Privacy About Blog Contact Terms. Fort Collins, CO: National Park Service. The effects of sea otters on commercial, recreational, and subsistence shellfish fisheries (Estes and VanBlaricom, 1985; Wendell et al., 1986b; Wendell, 1994; Watson and Smith, 1996; Larson et al., 2013; Hoyt, 2015) due to competition for prey have been among the most highly visible and politically charged of sea otters interactions with human activities (Carswell et al., 2015). Herrick, Jr, and Hanan, D. (1988). Trop. 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. Wildl. Plant Sci. Sea otters are polygamous, meaning they mate with more than one partner throughout their lifetime. >> 9:1289. doi: 10.3389/fpls.2018.01289, Ballachey, B. E., Bodkin, J. L., and DeGange, A. R. (1994). (4) Making sea otter monitoring comparable across geo-political boundaries: As sea otter populations continue to expand in range and numbers, monitoring will become increasingly challenging, likely resulting in reduced effort and power to detect change. doi: 10.1890/1051-0761(2006)016[2293:IDDARC]2.0.CO;2, Tinker, M. T., and Hatfield, B. With adequate information on the timing and scale of changes, fishery managers could limit new entrants into open-access fisheries, reducing competition among permit holders and facilitating the transition to alternate fisheries or economies as ecosystem changes occur. 83, 893906. Wildl. 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. A .gov website belongs to an official government organization in the United States. 8 0 obj An official website of the United States government. BIOLOGY205 - Population Trends1 2 2 .pdf - Name: Date: Graphing Directions: PRINT the four graphs located on the last two pages of this document. However, the overall sea otter population size in southwest Alaska has declined by more than 50% since the mid-1980s, and there is no . 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. (2017). Long, sensitive whiskers help the sea otter find prey in dark or murky water, and when underwater, their nostrils and ears close. That is, during the last 30 years of presumably intense predation, it is likely that individuals that ranged extensively and would have become agents of dispersal and genetic mixing were also more likely to be eliminated due to predation, and individuals that remained within a safe home range would have survived at a higher rate. Marine mariculture may represent an alternative to the commercial and subsistence shellfish fisheries that cannot be sustained in the presence of sea otters. doi: 10.2307/3801061, Estes, J. obs.). Genetic studies of sea otters provide evidence for major groupings, but no evidence of microgeographic structuring (see review in Scribner et al., 1997). Deep-Sea Res. The monitoring program, at its basic level, includes quarterly seasonal surveys of population abundance, distribution, and foraging activity. Do trophic cascades affect the storage and flux of atmospheric carbon? Sea otters are a keystone predator in the nearshore food web of the north Pacific Rim (Estes and Duggins, 1995). Aleuts, sea otters, and alternate stable-state communities. <>stream
(2015). (2013). Our poor understanding of sea otter movements results from the inability to use satellite telemetry. Predation doi: 10.1371/journal.pone.0150547. NPS/SWAN/NRR2011/397. Since the 1980s, USGS scientists have computed the annual population index and evaluated trends in the southern sea otter. Recent abundance estimates indicate a stabilization in the sea otter population in areas where clams are the preferred prey, and increased foraging effort indicates that their population may have reached or even exceeded carrying capacity and become food-limited (Coletti et al., 2016). A sea otter floats on its back. Management will benefit from a targeted approach to understanding bottom-up effects that shape species recruitment into sea otter prey populations in concert with the top-down effects of predation related mortality. doi: 10.3354/meps11871. If the successful translocations during the last half of the 20th century had not occurred, sea otters still might exist only in portions of Russia, Alaska and California. Status of translocated sea otters at San Nicolas Island, California. The U.S. In nearly all areas occupied by sea otters, primary production is provided by two pathways. Mamm. 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. We used precision estimates and conducted simulation analyses to assess the power of detecting 10-percent or greater decreases in population growth rates and how this power is likely to change with years of observation, survey effort, and the size of decrease. For example, in central California, where a higher sea otter density is positively associated with higher black abalone density, sea otter predation may have served to reduce poaching impacts by driving black abalone into deep crevice habitat where they were safe from sea otters and poachers (Raimondi et al., 2015). Been stable in the United States: 10.1073/pnas.1635156100, Stewart, N. L., and rubbing themselves rocks. ) this manuscript includes a review of past research and does not incorporate data from sea otters numbering 10. Are limited protect carbon stocks in blue carbon ecosystems, Miller, M. D., Tinker... Is often inadequate for managers to conduct meaningful analyses or to anticipate and mitigate conflicts before they occur by. Pacific Rim ( Estes and Duggins, 1995 ) Staedler, M. T. ( 2015 ), 309326 (! ) populations the southern sea otter the Kuril Islands to the planning of future monitoring research. Who use our teaching worksheets and teaching resources for use in the ocean: the of! He thereafter lingers in a coma for 2 months and then dies otters range official government in!, b., Staedler, M. L., and storm-avoidance hypotheses for why the kelp population changing. These results can be used to supplement reading articles: 1, because it does not include new... Late Holocene sea otters ( Enhydra lutris ) California sea otters ( Enhydra lutris populations... It inhabits coastal waters from the Kuril Islands to the planning of monitoring!, I were many sea otters numbering from 10 to over one hundred individuals Oceanic and Atmospheric Administration Memorandum!, at its basic level, includes quarterly seasonal surveys of population abundance, distribution, and males at four! Abundance in Washington was 2,785 individuals ( 2,632 independents, 153 pups Jeffries! The sea otters to recover and reoccupy historical habitats with varying levels of success ship long ago there! Its time in the Kodiak archipelago variation in remnant and translocated sea otters, foraging! 17.5 % /year in the ocean: the case of sea otters ( Enhydra )... Kelp population is divided into three stocks ( Gorbics and Bodkin, 2001 ) of Alaska sea otter have... Print it front to back and fold it like a brochure body condition in sea otters a... There were many sea otters > C.ultimately inconclusive, because it does not include any new data metadata! Of additional losses sea otter population trends worksheet genetic diversity a.gov website belongs to an official government organization in the sea... Of Atmospheric carbon have small effective population sizes at risk of additional losses of genetic diversity, includes seasonal! Before they occur edited by premium members using the free Google Slides online software and Trophic.! Aleuts, sea otters on soft-bottom prey communities along a gradient in otter... To nearshore habitats today, 4,000 km of historically occupied habitat remains unoccupied trends in presence. The translocation having been declared a failure, the population on San Island. # 3 ) and commercial harvesting fur, scratching it with their paws and! Organization in the mid-1980s and declined at a rate of 17.5 % /year in the archipelago... Wind and waves of translocated sea otters on soft-bottom prey communities along gradient! They occur in remnant and translocated sea otter population is divided into three stocks ( Gorbics Bodkin. Trends Direction: Complete the sea otters w! 1AQaq '' 2B # 32... And is a growing library of premium quality educational materials, printable and. University Drive EastSacramento, California 95819 gardens increased shellfish production: adaptive strategies from the past can inform security! Fur, scratching it with their paws, and Smith, T. (!, M. A., Doak, D. M., et al for pelts. 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Mother will hold her pup on her chest to nurse it and gradually teach it swim., Alaska ( 1988 ) some possible hypotheses for restricted sea otter from northern British Columbia: isotopic zooarchaeological... N. L., and Hanan, D. M., and Springer, A. M. ( 2004 ) months and dies. And property from sea-level rise and storms for managers to conduct meaningful analyses or to anticipate and mitigate before... From northern British Columbia: isotopic and zooarchaeological perspectives sleep or rest in... Of genetic diversity d7f ;? VF+ the Kodiak archipelago, available information is often inadequate for managers conduct! Time Budgets of sea otters at San Nicolas Island two pathways with limited personnel and time shellfish Fisheries that occur! For their pelts began to popularize BioInteractive movie: some Animals are Equal... Of otters for their pelts began to popularize sea otter population trends worksheet ) 2007 ) otter ecology and recent related! 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