1986; Ross et al. There are currently Canadian regulations and measures to minimize the risk of accidental spills (e.g. However, many new, unregulated chemicals are considered as ‘emerging’ concerns. However, given the recent abundance estimates for Steller Sea Lion in B.C. 2006, Mos et al. There are two recognized subspecies: western, PHOTOS: (CLOCKWISE FROM UPPER LEFT) M. MALLESON, M. NOLAN, V. SHORE, M. NOLAN, Glenn R. VanBlaricom, ... Robert L. Brownell, Glenn R. Van Blaricom, ... Robert L. Brownell, Encyclopedia of Biodiversity (Second Edition), Long-term Ecological Change in the Northern Gulf of Alaska, Data from the National Marine Mammal Laboratory, Seattle, WA. 2004). 2000; Benson and Trites 2002), and such changes may affect Steller Sea Lion prey distribution within B.C. Adult male (background) and adult female (foreground) Steller sea lions, Eumetopias jubatus. However, should extreme ecosystem changes occur that result in decreased prey availability, there may be high concerns for population level effects. Pathogens and diseases from terrestrial sources or exotic species are a concern in terms of exposure of the population to new biological contaminants. It should be noted that the current level of concern column reflects the concern for impacts from a threat at this time, and future assessments may result in levels of concern that differ from those presented here. 2007). Based on extensive research since the decline was first recognized, the current consensus opinion is that ecosystem change or competition with fisheries are the most likely factors driving the decline. Diving ability of pups and juveniles increases with age, and they routinely dive to depths of around 140 m for periods of 2 min as yearlings. As has been shown in other marine mammals, contaminant concentrations in Steller Sea Lions (predominantly organochlorines) are linked to age and gender. General increase in vessel traffic (motorized and self-propelled) along the B.C. Andrey Narchuk Asia Kamchatka marine mammals ocean Pacific Pacific ocean Russia sea sea lion Steller sea lion underwater. The first rookeries became established in SE Alaska during the 1930s or 40s when the intense killing had begun in southern parts of the range, and the species appears to have flourished in the 1950s and 60s even as breeding populations were reduced in B.C. On le trouve depuis le sud de la Californie le long de la côte du Pacifique jusqu'au Japon septentrional, mais la plupart se reproduisent entre le Golfe central de l'Alaska et … L'eider de Steller est classé «vulnérable» par l'UICN et figure à l'annexe 1 de la directive «Oiseaux» de l'UE, comme le plongeon catmarin, le plongeur arctique, le grèbe esclavon et le harle piette. A regime shift that alters prey abundance from a high to low energy prey species (e.g. When managers of the Pribilof herd learned that age at first reproduction of the Russian herd was, on average, 1 year younger than in the Pribilof herd, they justified a large reduction of females in the Pribilof population with the idea that with a lower herd density age at first reproduction would decrease to the level of the Western Pacific population, and a sustainable harvest of the same size would be obtained from a reduced population. They have recently been separated into three genetically distinct stocks: the Eastern Stock along the west coast of North America from California to southeastern Alaska; the Central Stock from Kayak Island west to the Commander Islands at the western end of the Aleutian Archipelago; and the Western Stock from the Commander Islands and western Bering Sea south to Japan (Bickham et al., 1996; Baker et al., 2005) (Fig. 2005). The rate of decline has varied over time, with highest rates (approximately 15% per year) from 1985 until 1990. Breeding bulls are also very thick and wide in the neck and shoulder area. aerial surveys indicate that numbers of pups and non-pups on rookeries increased at a mean rate of 3.5% and 3.9% per annum respectively, which has resulted in a tripling in the size of the breeding population since the early 1970s (Figure 5) (DFO 2008). Thus, Steller Sea Lion reproductive biology may not have the plasticity to adapt to disturbances near breeding colonies. Adult males gain a huge amount of weight on the run-up to their breeding season Loughlin’s Steller sea lion, British Columbia, Canada. 2007; Burkanov and Loughlin 2007). This assessment is a current view of the state of threats to the population, and as such assessment ratings may change over time. All are currently managed to prescribed catch levels, which are believed to be sustainable. A shift in the quality of diets from fatty fishes (i.e. Committee on the Alaska Groundfish Fishery and Steller Sea Lions. Breeding populations of Steller sea lions have been reported as far south as San Miguel Island (this population disappeared in the 1970s). 2006). 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. Longevity is 20 years in males and up to 30 years in females. Environmental Contaminants – Persistent Organic PollutantsPersistent environmental contaminants such as organochlorine pesticides (e.g. They appear to feed over the continental shelf and along the shelf break (Kajimura and Loughlin 1988). 1998) provides further evidence of nutritional stress during the steep declines in the Western Population observed during the 1980s (NMFS 2008). 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%. In addition, guidelines (Be Whale Wise: Marine Mammal Viewing Guidelines for Boaters, Paddlers and Viewers, 2006) have been established to address disturbance from close approaches whether on land or sea, and are often followed for pinniped viewing. There is relatively poor understanding of how Steller Sea Lions use their aquatic habitat At sea, Steller Sea Lions are commonly seen alone, or in groups of several animals (Bonnell et al. In general, most Steller Sea Lions appear to feed within about 60 km of shore during summer, and can range over 200 km from shore in winter (Kenyon and Rice 1961; Merrick and Loughlin 1997). 10. Further, management of sources of outflow and runoff may assist in mitigating this threat. Steller Sea Lion populations are ultimately limited by the availability of suitable prey. Similar trends have been observed on neighbouring rookeries to the south in Oregon and to the north in SE Alaska (Figure 5), which combined constitute 90% of the Eastern Population (Brown and Reimer 1992; Calkins et al. Canadian seismic surveying standards assist in mitigation of this threat. The worldwide population of Steller sea lions is estimated to be 143,000, with different trends in the eastern and western portions of its range. DDT), polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and polybrominated diphenyl ethers (PBDEs) bioaccumulate in marine food chains. Steller Sea Lions are an important prey species for Transient Killer Whales (also called transients), (Morton 1990; Baird and Dill 1995; Ford et al. Resolution of the question of cause has become the focus of intensive political interest because of the potential economic consequences of resulting recovery actions by management authorities. 1996; Melin and DeLong 2000). Fisheries and Oceans Canada, Conservation and Protection Branch responds to, as necessary, and investigates reports of unauthorized lethal take (including attempts) and disturbance to all marine mammals, in the course of general operations. This is especially true for B.C. (Table 1). The maximum size of the subsistence take is set by the PBR approach at about 15,000 animals, well above the mean annual take from 2000 to 2004 of 750 animals. 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. Additionally, sources of contamination that originate in Canada may be mitigated, whereas for contamination that may originate in international waters, the mitigation potential is very low from a Canadian management perspective. The area used by adult females for foraging in winter is considerably larger than the area used in the summer. 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. may foster an increased understanding of dispersal among rookeries, and the genetic makeup of individuals re-colonizing the rookery on the Sea Otter Group. As uncertainties on the level of toxic loading in Steller Sea Lions in B.C. English. español: León marino de Steller; فارسی: شیر دریایی اشتلر; suomi: Stellerinmerileijona; français: Lion de mer de Steller; עברית: אריה ים שטלר; magyar: Steller-oroszlánfóka; Bahasa Indonesia: Singa laut steller; 日本語: トド; ქართული: ზღვის ძაღლი; 한국어: 큰바다사자 Ses mâchoires sont suffisamment puissantes pour broyer ses proies. Sexual dimorphism is evident, with adult males that weigh three times as much as females, and grow 20–25% longer. Median estimates of time to extinction range from 62 to 160 years. There are unexplained declines in other populations to the north and west of British Columbia.Canadian Occurrence: British Columbia, Pacific Ocean. Although the population is increasing, they are sensitive to human disturbance while on land. In Washington, the state government offered a bounty payment for Steller Sea Lion kills, and abundance along the Washington coast fell from several thousand in the early 1900s to fewer than a hundred by the late 1940s. There is considerable evidence to suggest that nutritional stress played a role in reducing both the recruitment and the reproductive rates of Steller sea lions (DeMaster and Atkinson, 2002). Lion de mer de Steller. An Adult male Loughlin’s Steller sea lion vocalizing. Predation by Killer WhalesAs outlined in ‘Limiting Factors’, killer whales are an important predator having the potential to limit Steller Sea Lion populations. 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: … In B.C., sea lions are occasionally seen rafting as far as 35 km upriver (Olesiuk, unpublished data).
Exercices Théâtre émotions Pdf, Portail Famille Riorges, Rtm Abonnement Annuel Boursier, Formulaire Autorisation De Lemployeur Pour Les Candidats Salariés, Certificat De Mariage à Remplir, Porte Vélo Thule Occasion Le Bon Coin, Claude Giraud Et Sa Femme, éclatée Tondeuse Honda Hrd 536, Marius En Italien, Match Lens St Etienne Chaîne, Paris Nîmes Direct, Boutique Sncf Gare De Lyon,