Our work includes: Our research has discovered new aspects of Steller sea lion biology, behavior, and ecology and helped us better understand the threats to Steller sea lion individuals and populations. Species characteristics Steller sea lions are the largest otariids and the fourth largest pinniped. Full-grown male Steller sea lions are … Adult males are known to occasionally kill and consume young northern fur seals, harbor seals, and in one case, a juvenile California sea lion.
Illegal feeding, Alaska, The groundfish fisheries off Alaska target several Steller sea lion prey species, which can negatively impact Steller sea lions and their critical habitat. comm.).
Weaning often takes place before the next breeding season, but it is not unusual to see females nursing yearlings, older juveniles, or multiple offspring. As pups get older the amount of time spent by females foraging out at sea increases.This continues until pups obtain the ideal body weight and energy reserves in order to eat on their own. In addition to those adaptations, their thick blubber layer and outer fur layer keep their body insulated during dives. Kuril Islands, Russia. The eastern DPS includes Steller sea lions originating from rookeries east of Cape Suckling.
Females weigh half as much, despite being just a few feet shorter than the 11-foot males.
Steller sea lions can be injured or killed if they are disturbed when they are hauled out.
Federal agencies that undertake, fund, or permit activities that may affect these designated critical habitat areas are required to consult with NOAA Fisheries to ensure that their actions do not adversely modify or destroy designated critical habitat. Steller's sea lions occur in coastal waters of the North Pacific Rim from southern California to northern Japan and in the Bering Sea and Sea of Okhotsk.
Their suckling time, and age and gender are unrelated to their use of energy. Repeated disturbances that cause lactating females to abandon rookeries or use them less could damage the health and survival of pups by threatening normal nursing cycles. Determination that competition with fisheries is contributing to the decline could result in forced reduction of fishing effort, with great economic loss and political discord. A Eumetopias jubatus rookery with adult females and males. Ecological Significance of Residual Exposures and Effects from the Exxon Valdez Oil Spill. [44] Other hypotheses include increased predation by orcas[45] and sharks,[46] indirect effects of prey species composition shifts due to changes in climate, effects of disease or contaminants, shooting by fishermen, and others. Females begin to arrive on rookeries in mid-May. Female (top), and male (bottom) Loughlin’s Steller sea lions seen passing under the Golden Gate Bridge. Among pinnipeds, it is inferior in size only to the walrus and the two species of elephant seals. The present management objectives are to maximize economic return while maintaining the population over the 70% reference level, with an estimated probability of at least 80%. It is the sole member of the genus Eumetopias and the largest of the eared seals (Otariidae).
In 2007, the catch was 225,000 (more than 95% are young of the year).
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They formerly bred as far south as the Channel Islands, but have not been observed there since the 1980s. For the best experience, please use a modern browser such as Chrome, Firefox, or Edge. Glide velocity of individual Steller sea lions has been measured as 2.9–3.4 meters or 1.2–1.5 body lengths per second, which is close to the optimal swim velocity of 1.4 body lengths per second based on the minimum cost of transport for California sea lions. [25] Twins are rare.
Determination that competition with fisheries is contributing to the decline could result in forced reduction of fishing effort, with great economic loss and political discord.
Taxonomic information Carnivora, Otariidae. Vagrants have also been reported from the coast of China in the Yellow and Bohai seas. This hotline is available 24 hours a day, 7 days a week for anyone in the United States.
The age at weaning is highly variable; pups may remain with their mothers for as long as four years. (a) Trends in Steller sea lion populations in the central and western GOA (blue) and the northeastern GOA (red). Loughlin published Using the phylogeographic method to identify Steller sea lion stocks | Find, read and cite all the research you need on ResearchGate
Careful attention to head and muzzle size and shape, overall coloration, and length and width of fore- and hindflippers permits separation. Moreover, studies such as Trites et al. The general pattern of increasing δ15N values among Steller sea lions supports previous conclusions regarding a reduction or redistribution of forage fishes and an increase of demersal and semi‐demersal species in the North Pacific ecosystem. There are two recognized subspecies: western Steller sea lion (E. j. jubatus), and Loughlin’s Steller sea lion (E. j. monteriensis), as recently adopted by the Society for Marine Mammalogy.
Compound‐specific amino acid δ15N values in archaeological shell: Assessing diagenetic integrity and potential for isotopic baseline reconstruction.
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The Plan identifies major action categories related to the western DPS, aimed at achieving four broad goals: While the Plan identifies many specific recovery actions for the western DPS, it highlights four actions as especially important: For the eastern DPS, the Plan recommended that NOAA Fisheries conduct a status review to determine if the DPS should be delisted.
includes all Steller sea lions originating from rookeries west of Cape Suckling (144° west longitude). Steller sea lions may be affected by commercial fishing directly through incidental catch in nets, by entanglement in derelict debris, by shooting, or indirectly through competition for prey, disturbance, or disruption of prey schools (Alverson, 1992). Cape Olyutorsky, Russia. The deepest dive documented is about 1,400 feet in depth.
Several groups have argued that this decline is due in part to the large fishery harvest of walleye pollock (Theragra chalcogramme), simultaneously a key source of food for sea lions and the most important US commercial fishery. Unlike most pinnipeds, when wet, adult Stellers are the same color or paler depending on lighting, appearing light grayish-tan. Adult females are about 2.5 m and 273 kg.
[1], Steller sea lions are top-tier carnivores, but are susceptible to predation, primarily by killer whales. [30], A 2007 study of Steller sea lions found that a majority of thrust was produced during the drive phase of the fore flipper stroke cycle.
Data for southeastern Alaska from, Virus Cycles in Aquatic Mammals, Poikilotherms, and Invertebrates, Éva E. Plagányi, Douglas S. Butterworth, in. Amendments to the, in 1988 and 1994 required observer programs to monitor marine mammal incidental take in some domestic fisheries and NOAA Fisheries provides estimates of mortality and serious injury of Steller sea lions due to US commercial fisheries in. Although previous findings on eared seals suggested that thrust was generated by the initial outward movement of the foreflippers or the terminal drag-based paddling phase, the 2007 study found that little or no thrust was generated during those phases. High-arctic seabird trophic variation revealed through long-term isotopic monitoring. The ESA requires us to conduct these 5-year status reviews to ensure that the listing classifications of species are accurate.
The two populations of Steller sea lions differ genetically and morphologically, and have contrasting population trends.
Photo: Alaska Department of Fish and Game. This was accomplished and the eastern DPS was delisted in late 2013.
Global climate change is expected to have profound impacts on arctic and sub-arctic marine ecosystems.
Ultimately, we seek to have the species recover so the ESA’s protections are no longer needed to stave off its extinction.
Adult fur color varies between a light buff to reddish brown with most of the under parts and flippers a dark brown to black; naked skin is black. The rate of decline has varied over time, with highest rates (approximately 15% per year) from 1985 until 1990. Because of unexplained widespread population declines in Alaska, Steller sea lions were first listed under the Endangered Species Act (ESA) in 1990. In recent years, Steller sea lions have been known to enter the Columbia River estuary and feed on white sturgeon, several salmon species, and rainbow trout, some of which are also listed under the U.S.
Numbers of Steller sea lions in the western Aleutian Islands of Alaska crashed in the 1970s and 1980s. By continuing you agree to the use of cookies.
Help us find out why the endangered Steller sea lion continues to decline in the Aleutian Islands. Within their bulbous bodies, Steller sea lions of the western Aleutian Islands seem to carry more mercury than sea lions closer to mainland Alaska.