These populations have local movements and migrations, with feeding cycles that occur near shore that can be daily. Steller Sea Lion populations are ultimately limited by the availability of suitable prey. Protection from DisturbanceSection 7 of the Marine Mammal Regulations (Fisheries Act) prohibits the disturbance of marine mammals, unless authorized by a fishing licence or scientific licence. 2007), resulting in population decline. The western population numbered approximately 150,000 animals in the 1950s, but has since declined precipitously, with current total numbers, including US and Russian habitats, estimated at between 58,000 and 66,000 individuals. Pups are born with a thick blackish-brown natal coat that is molted by about 6 months of age. Thomas R. Loughlin, Thomas S. Gelatt, in Encyclopedia of Marine Mammals (Third Edition), 2018. From the Aleutians they range north across the Bering Sea to the Bering Strait. For U.S. stock assessments, a theoretical maximum growth rate of 12% is generally assumed for pinnipeds. Official recognition of the distinction between the Central and Western Stocks has not yet occurred, and they are still grouped together as the “Western Stock” under the Endangered Species Act. In 2004, license conditions were modified to remove Steller Sea Lions from the permits to eliminate the use of lethal control for this species due to the COSEWIC designation of this species as special concern. This regulatory tool restricts manufacture and use of several types of PBDEs in Canada, and is a first step toward long term reduction in environmental toxic effects from PBDEs. However, data on these activities are currently lacking, and incidents that occur in remote locations are inherently more difficult to document or monitor. A juvenile that still has a lot of growing-up to do. California sea lions migrating along the coast of Oregon appear to displace Steller Sea Lions (Mate 1975); the two species often share the same winter haulout sites (P. Olesiuk pers. For females, these daily energy requirements represent about 14% of body weight for a 1 year old and 7% for a mature individual. 2002). As the environmental presence and overall usage of emerging, unregulated persistent organic pollutants (POPs) is increasing, the level of concern for this threat is moderate1, while concern for regulated, legacy contaminants is deemed low to moderate (Table 1). Native Alaskans currently take between 150–300 a year for food and other uses. Given the trans-boundary distribution and high mobility of Steller Sea Lions, population assessments need to be coordinated among jurisdictions. The species is gregarious while on land, and animals gather at traditional rookeries and haulout sites, some of which have been used for over a century. They once bred in the Channel Islands, but are now rarely seen south of Monterey Bay. Currently, the Steller Sea Lion population in B.C. In southern B.C., winter haulouts are often shared with subadult and adult male California sea lions (Zalophus californianus) (Hancock 1970; Brenton 1977; Bigg 1985). The magnification of such chemicals with increasing position in the food web predisposes many marine mammals to becoming highly contaminated. 1976; Martin et al. 1999; Pitcher et al. 2006). BrownellJr., in Encyclopedia of Biodiversity (Second Edition), 2013. However voluntary industry-based training is conducted. French: lion de mer de Steller; Italian: leone marino di Steller m; Japanese: 胡獱 (トド, todo) Korean: 큰바다사자 (keunbadasaja) Lithuanian: šiaurinis jūrų liūtas; Norwegian: stellersjøløve; Polish: uchatek grzywiasty, uchatka grzywiasta, lew morski Stellera; Portuguese: … However, whereas non-pup abundance fell, the number of pups produced each year did not, suggesting that perhaps the “resident” population remained stable while numbers of visiting sub-adults from other regions of the GOA declined (K. Pitcher, pers. Its latin name is Eumetopias jubatus. Sexual dimorphism is evident, with adult males that weigh three times as much as females, and grow 20–25% longer. 1996; Loughlin 1997). Un grand nombre de lions de mer de Steller (Eu- metopias jubatus) ont été attirés par des rassemblements préparatoires à la fraye d’eulakanes ( Thaleichthys pacificus ) dans la baie de Berners dans le sud-est de l’Alaska en avril et en mai 2002 et 2003. The higher mortality rates for males’ results in a progressively skewed sex ratio favouring females. 2002). Interestingly, self propelled vessels (such as kayaks) are demonstrated to elicit behavioural responses from pinnipeds on haulouts (Henry and Hammill 2001), possibly due to these disturbance stimuli illustrating perceived predation risk (Deecke et al. Of particular uncertainty is their diet outside of the breeding season. Gwaii Haanas National Marine Conservation Area (NMCA) in the southern Queen Charlotte Islands is proposed under the Canada National Parks Act and National Marine Conservation Areas Act to extend 10 km offshore from Gwaii Haanas National Park Reserve and Haida Heritage Site potentially protecting marine habitat for Steller Sea Lion in the area. Likewise, sea lions of the Eastern Stock in British Columbia have also increased considerably in the past three decades, recovering from effects of control programs there in the 1950s and 1960s that reduced their number from about 14,000 when the first survey was conducted in 1913 to about 3400 by the early 1970s (Bigg, 1985; Olesiuk, 2003). 2007). Limiting factors are the natural processes that limit population size or growth. carnívors > pinnípedes > otàrids; Traduccions Nonetheless, Steller Sea Lions at winter feeding sites often habituate to chronic disturbances, and some haulout sites are located in high traffic areas close to major urban centres such as Vancouver and Victoria (Bigg 1985; P. Olesiuk pers. The bones of the three central toes terminate at the position of the small nails that emerge through the skin on the dorsal surface, set back from the end of the flipper. An adult male Loughlin’s Steller sea lion on with a juvenile California sea lion in southern California. Comparison with Figure 3 shows the impact these kills had on populations. Oregon Zoo reopening; Zoo map; Calendar; Hours and admission; Today at the zoo; Plan your trip; Food at the zoo; Gift Shop; Washington Park and Zoo Railway Information on key vital rates of Steller Sea Lions are required to determine age and sex specific fecundity and survival rates, age at weaning, and age of first reproduction that regulate population productivity. The later papers estimated time-varying vital rates that were consistent with the non-pup and pup counts and juvenile index data, assuming that the known vital rates were from the sampled animals at time 0. (Bonnell et al. The dental formula for the permanent teeth is i 3/2, c 1/1, pc 5/5, total 34. as Part of Control Programs and Commercial Harvests During 1913-70. 1998; Pitcher et al. Toxic SpillsSea lions may be impacted by catastrophic accidents such as toxic spills (St. Aubin 1990), although the impact on a population-wide scale has rarely been established. Two hundred or more may be taken a year in Alaska. Therefore, the importance of long-term monitoring of the population cannot be overstated. The cause or causes of long-term decline in the western population of Steller's sea lions are not understood. The Northwest Atlantic harp seal (Pagophilus groenlandicus) population in Canada and Greenland is currently subject to a harvest. Steller sea lions suffered a significant decline in the western area of their U.S. range from the late 1970s through the 1980s (Braham et al. Factors hypothesized include the direct and indirect effects of large-scale commercial fisheries on key prey species, long-term ecosystem shifts, changes in distribution of prey and availability of prey types, and changes in killer whale predation. After 1918, the harvest was conducted under the auspices of the Treaty on the Conservation of the Northern Fur Seal (see Northern Fur Seal). Lion de mer de Steller. Two subspecies are recognized (Phillips et al., 2009), the eastern subspecies (Eumetopias jubatus monteriensis) includes animals occurring from California to Cape Suckling (144°W), near Prince William Sound, AK. herring) to low-fat fishes (i.e. 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). Acoustic disturbance such as explosions, seismic or military tactical sonar noise may cause displacement of animals from feeding areas, and disrupt foraging behaviour. The rate of decline has varied over time, with the highest rates (approximately 15% per year) from 1985 until 1990. As mentioned above, severity of population level impact is low for haulouts, but moderate for disturbance to rookeries due to site fidelity, potential energetic costs for mothers and pups, and pup survival (Table 1). Predator Control ProgramsFor most of the 20th century, the main factor limiting Steller Sea Lions along the west coast of North America was predator control programs. This interpretation is supported by counts at two prominent haul outs, The Needle in Montague Strait (PWS) and Cape St. Elias on Kayak I., where numbers plummeted by an average of at least 80% in the interval 1989–1990 to 1996 (Fig. Adult males add a considerable amount of weight in late winter and spring, before the summer breeding season, and slim down afterwards. The same local-scale variance in trend is known for the eastern population. Aboriginal hunting of Steller Sea Lions for subsistence and cultural purposes does occasionally occur in Canada, but harvest levels are unknown. It is estimated that about 14,000 animals (all ages, including pups) were present on rookeries in 1913-19 (Fig. Environmental Contaminants – Persistent Organic PollutantsPersistent environmental contaminants such as organochlorine pesticides (e.g. These studies have provided over 750 primary citations, journal articles, progress and technical reports, contract reports, proceedings of conferences and symposia, books, thesis and other manuscripts. Journal du Conseil International pour l’Exploration de le Mer 169:455-461. The extent of illegal killing of pinnipeds is poorly understood and the impact of such activity at a population-level is unknown. The diving of adult males has not been studied. Given that other unknown compounding factors were not at work, these data suggest that during gestation or the first year of life something caused stunting of growth that was never overcome. The current estimate of the population is 5.4 million (Hammill and Stenson, 2007); approximately 18–20% of the population is young of the year. Major wintering areas of sea lions off southern Vancouver Island have shifted, presumably in relation to changes in distribution of pre-spawning herring (P. Olesiuk, pers. Such a dynamic should, and apparently does, sustain caliciviruses within this species (Barlough et al., 1987, 1988) far more effectively than occurs in fur seals, where only seasonal direct contact occurs and feeding and fecal discharge are predominantly offshore in deep water. Both males and females are robust and powerfully built at all ages. Interdecadal Changes in Mesoscale Eddy Variance in the Gulf of Alaska Circulation: Possible Implications for the Steller Sea Lion Decline Arthur J.Miller1*, Emanuele Di Lorenzo2, Douglas J. Neilson1, Hey-Jin Kim1, Antonietta Capotondi 3, Michael A. Alexander, Steven J. Bograd 4, Franklin B. Schwing, Roy Mendelssohn4, Kate Hedstrom 5and David L. Musgrave 1Scripps Institution of … 1999; Pitcher et al. Further genetic samples of the population within B.C. Within Canada, Steller Sea Lions occur only in British Columbia and constitute part of the Eastern Population (Bickham 2000). Total abundance in the United States and Russia of this subspecies was estimated to be 78,000 in 2011. Quarterly reports filed by licence holders indicate that a total of 362 Steller Sea Lions plus 21 sea lions for which species could not be identified, were killed from 1990 (when the first permits were issued) up to 2003. and neighbouring waters have now recovered past historic high levels, natural population regulatory mechanisms might become a factor governing the status of Steller Sea Lion populations. 4.50(a)). comm.). As such there is moderate potential for successful mitigation of this threat. Disturbance on and around Terrestrial HabitatRepeated disturbances of breeding or haulout sites by aircraft, boats, pedestrians, construction, or fishing activities (e.g.
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