lion de mer steller

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. This will result in future improvements regarding information on entrapment rates of Steller Sea Lions in aquaculture gear. Also, smaller Stellers have little or no sagittal crest development and a nearly flat-topped head whereas comparably-sized adult and subadult California sea lion males have a moderate to large sagittal crest and more pronounced forehead. They posit that, paradoxically, Steller sea lion and northern fur seal (Callorhinus ursinus) populations might realize greater benefits if adult pollock and large flatfish were more heavily fished. displacement from feeding areas), Incidental take - fisheries and aquaculture, Low, potentially severe effects on individual animals, Effects can be enhanced by synergistic effects of threats, Regulated and unregulated contaminants of concern are listed in, The vast number of pinniped entanglements (110 out of 170) can be attributed to shark guards used at one site, and these have since been removed (, Steller sea lion (Eumetopias jubatus) management plan,, The effects of research activities such as disturbances at haulouts and especially rookeries and hot-branding on pup survivorship, Baseline levels of chemical and biological pollutants in the B.C. The surprisingly high ratio of non-pups to pups observed in surveys along the west coast of North America suggests that increased juvenile survival (as opposed to increased natality rates) may have been an important factor influencing growth of the Eastern Population (Pitcher et al. In combination, the factors of reproductive failure — including abortion, decreased numbers of surviving pups, and poor first-year growth performance — were all operating to erode the Steller sea lion population base. After 1918, the harvest was conducted under the auspices of the Treaty on the Conservation of the Northern Fur Seal (see Northern Fur Seal). Since 2000, the trend has been a slight increase in numbers overall, but the western Steller sea lion DPS remains Endangered under the US Endangered Species Act. Further research may be necessary to address knowledge gaps on the rate of entanglements and their effect on a population-wide scale. L'animal est donc reparti sans blessure. As a population-wide impact has been illustrated to be unlikely, concern for catastrophic spills affecting the population has been rated low (Table 1). Controlled-feeding studies have shown that sea lions, particularly young animals, consuming large amounts of low-fat prey such as pollock, may be unable to maintain body mass (Rosen and Trites 2000c; Azana 2002). Sightings at sea are most often of groups of 1–12 animals. The eyes of Steller sea lions also seem smaller and set farther apart, due to the proportionately larger head and wider muzzle. The role of seals and sea lions in complex marine ecosystems remains poorly understood and studies are required to assess the contribution of the Steller Sea Lion in large and complex ecosystems (Beverton 1985; Bowen 1997; Merrick 1997; Trites 1997). 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. were all well established when the first sea lion survey was conducted in 1970 (Newcombe and Newcombe 1914),  and  have been used continuously despite disturbances caused by predator control programs and commercial harvests (Pike and Maxwell 1958; Bigg 1985; Olesiuk unpublished data). Steller Sea Lions have a polygynous mating system, in which bulls compete to establish territories and gain access to females; the ratio of cows to territorial bulls is generally about 10-15:1 (Gisiner 1985; Merrick 1987). 2008). However, with a population growth rate of about 4.5% per annum, a relatively small increase in human-induced mortality could become an important factor if conditions for Steller Sea Lions deteriorate, or if combined with other threats. for predator control or subsistence harvest). Scars from bites and healed wounds are darker than the background color. Recent rulings in US federal courts have restricted fishing activity in some locations and seasons for the purpose of reducing the rate of decline, intensifying the associated political debate. Vessel disturbance of pinnipeds at haulouts can reflect a suite of influences, including vessel type and number, speed, and distance from animals (Henry and Hammill 2001; Szaniszlo 2005). Thomas A. Jefferson, ... Robert L. Pitman, in Marine Mammals of the World, 2008. Much of the information on diet comes from animals living in Alaska, where they feed on walleye pollock, Pacific cod, Atka mackerel, herring, sand lance, several varieties of flatfish, salmon and rockfish, and invertebrates such as squid, octopus, bivalves and gastropods and numerous other species. Vessel disturbance of pinnipeds is managed via guidelines for viewing marine mammals. has exceeded historic peak abundance levels. to census animals, capture pups for tagging or branding) appears to be highly disruptive and often causes animals to escape into the water or to nearby haulouts (Lewis 1987; Scordino 2006; Olesiuk, unpublished data). This pattern was observed for four virus serotypes (Barlough et al., 1987). Le lion de mer de Steller ou otarie de Steller (Eumetopias jubatus) est la plus grande des espèces d'otaries et peut vivre jusqu'à 51,6 ans. Add a translation. Considering that over 70% of pup production in B.C. The precipitous decline of the Western Population has made the Steller Sea Lion one of the most intensively studied marine mammals in the world (see NMFS 1992, 2008; Loughlin 1998; Hunter and Trites 2001; Dalton 2005). Large sharks may also prey on Steller Sea Lions in the southern part of their range (Stroud 1978; Ainley et al. 2007). Genetic data have been used as the basis for dividing the species into two populations, western and eastern, with the boundary at Cape Suckling (144° W longitude), Alaska. Given the trans-boundary distribution and high mobility of Steller Sea Lions, population assessments need to be coordinated among jurisdictions. All sea lions are remarkably agile on land due to their ability to rotate their hind flippers forward and prop themselves up on their foreflippers. Other common names used in Canada include Steller’s sea lion, northern sea lion and lion de mer de Steller. However, fishing activity may be intensive near important sea lion breeding locations, and it has not been possible to eliminate competition with fisheries as a potential cause of the decline. Newborn pups are 1 m and 16–22 kg. Surveys are conducted during a brief time window between late June and early July, representing the period by which most pups have been born, but most are still too young to have begun to disperse from rookeries (Bigg 1985; DFO 2008). geoduck and urchin dive fisheries) can lead to animals temporarily leaving haulouts and rookeries (Sandegren 1970; Calkins and Curatolo 1980; Johnson et al. A pale adult female vocalizing. Therefore the importance of targeted research programs addressing knowledge gaps, and long-term monitoring of the population and of identified threats cannot be overemphasized. unpublished data). The ‘current level of concern’ and ‘mitigation potential’ for each threat is identified (Table 1). 2002; Frid and Dill 2002). When dry, the fur of adults and juveniles are pale yellow to light brown, darkening to chocolate brown on their hindquarters and near their flippers, which are black and bare-skinned. (Table 1). population was incorporated into the assessment to provide a measure of confidence in the rating of current ‘level of concern’ and to provide an indication of areas where further monitoring or study may be useful in addressing uncertainties or knowledge gaps. Adult male Loughlin’s Steller sea lion next to a fairly large adult male California sea lion. 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 Figure 1. However, recent genetic sampling indicates two newly established rookeries near the western edge of the Eastern Population may have been colonized by a mixture of Western and Eastern stock animals (O’Corry-Crowe et al. 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. Though they can reach depths of 400 m, diving is generally to 200 m or less and dive duration is usually 2 min or less, with both parameters varying by season and age of the animal. Other common names used in Canada include Steller’s sea lion, northern sea lion and lion de mer de Steller. Entanglement in derelict gear is rare and unlikely to have contributed to the decline. Animals can get trapped in trawl nets or caught (entrapped) in drift and gill nets, and ultimately drown (Loughlin and Nelson 1986). [National Research Council (U.S.). While they are the only living member of their genus, they share parts of their range with a smaller related species, California se… Some First Nations names for sea lion include; tukuk or tukukw (tukwašt meaning dried sea lion) in Nuu-chah-nulth Barkley Sound dialects (BSDWG 2004), in Kwakiutl sea lion are referred to as tl’í x 7en (Grubb 1977), and in the Haida language, kíit or kíidaay (Lawrence 1977). Because natural oceanographic changes can neither be predicted nor controlled, management authorities may have no choice but to focus on understanding and minimizing anthropogenic risk factors, despite the political consequences, in order to reduce the probability of eventual extinction. As Steller Sea Lions recover from predator control programs and harvests, it is likely that prey resources will ultimately limit sea lion populations, but it remains unclear to what extent sea lions themselves might limit their prey populations. Approximately half of the sites were noted to exist during the first surveys in 1913 (Newcombe and Newcombe 1914), while about one-quarter appear to have been colonized since aerial surveys were initiated in the early 1970s. The mitigation potential column (Table 1) refers to the likelihood that measures (future or existing) will adequately mitigate or prevent negative effects to the population. There are four main breeding areas in B.C. lUCN status Near Threatened overall. 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. This text provides the background information used to determine the overall level of concern for the impact of each threat to the Eastern Population (Table 1). Steller Sea Lions forage on a variety of prey items, primarily small or medium-sized schooling fish, and foraging habitat varies in relation to prey distribution and abundance. 1990, Olesiuk unpublished data). The fourth breeding site in the Sea Otter Group was eradicated by predator control programs, although sea lions continued to use the site as a non-breeding haulout. The number of Steller Sea Lions killed annually was initially low (averaging less than 10), but escalated in the late 1990s and peaked at 91 in 1999 (Jamieson and Olesiuk 2001), likely as a result of a shift in winter distribution of sea lions from Barkley to Clayoquot Sound (P. Olesiuk pers. Steller Sea Lion fur is comprised of short coarse hairs, which is moulted annually between late June and early December, depending on the age class (Scheffer 1964). BrownellJr., in Encyclopedia of Biodiversity (Second Edition), 2013. Glenn R. VanBlaricom, ... Robert L. These reserves were established in 1971 by the Province of British Columbia to protect biodiversity. The marine debris documented to cause entanglements results mainly from lost fishing gear. Because natural oceanographic changes can neither be predicted nor controlled, management authorities have no choice but to focus on understanding and minimizing anthropogenic risk factors, despite the political consequences, in order to reduce the probability of eventual extinction. apparently followed a pattern similar to that in the central and western GOA, except that in the eastern Aleutians it may have begun somewhat earlier, perhaps by the early to mid-1970s. 1981) and sleeper sharks are a potential sea lion predator in Alaska (Sigler et al. Prey species composition has changed, dietary diversity has declined, and there have been measurable shifts in the spatial distributions of preferred prey during the past three decades. Predation rate on Steller Sea Lion may be increased due to synergistic effects with other threats or limiting factors. At present, there is no commercial harvest, but a subsistence take for food is permitted. Adult females are about 2.5 m and 273 kg. As uncertainties on the level of toxic loading in Steller Sea Lions in B.C. Copyright © 2020 Elsevier B.V. or its licensors or contributors. Following this period of attendance, females make foraging excursions, primarily at night for periods of 18–25 hours, followed by time ashore to nurse their pup. Kuril Islands, Russia. 2003, 2007). 2000; Benson and Trites 2002), and such changes may affect Steller Sea Lion prey distribution within B.C. A series of modeling papers has attempted to determine the demographic causes of the decline and how they may have changed over time. By continuing you agree to the use of cookies. However, calicivirus activity among reproducing females was seen (Barlough et al., 1987). Olesiuk et al. There are several threats which may affect this population in British Columbia. steller's eider. Figure 4.49. Although Steller Sea Lions generally return to breed on their natal rookery, there may also be some exchange between neighbouring rookeries (Calkins and Pitcher 1982, 1996). Pacific Whale Watch Association Best Management Practices ( ) and the public). Targeted enforcement of disturbance is focusing on whale oriented viewing, but also addresses the disturbance of pinnipeds, especially when hauled out near populated areas. Steller Sea Lions are widely perceived to be an important component of the coastal marine ecosystem, and contribute to the eco-tourism industry. 2006; Trites et al. Average standard length of males is 282 cm and of females 228 cm (maximum 325 and 290 cm, respectively). Fetuses presumably infected near full term in 1985 had neutralizing antibodies against caliciviruses, as did their dams. In B.C., government predator control programs eradicated a major rookery on the Sea Otter Group by the late 1930s, and numbers of sea lions breeding at the remaining rookeries had been reduced to about one-quarter of historic levels by the late 1960s (Bigg 1985). lleó marí de Steller m. ‎(plural lleons marins de Steller) Espècie d’otàrid que viu a les costes del Pacífic septentrional (Eumetopias jubatus) Hiperònims . Although there have not been well-defined calicivirus epidemics passing through the Steller herd as occurred with fur seals, calicivirus presence has been documented to be far more common (Barlough et al., 1987, 1988). 2006). Canada uses a management scheme referred to as “Objective Based Fisheries Management.” They have identified upper and lower reference points of 30 and 70% of the historical maximum population. Based on estimated pup production during the last range-wide survey in 2002, the total size of the Eastern Population is estimated to be between 46,000 to 58,000 animals, with about one-third (33% of pups and 34% of non-pups) occurring in Canadian waters. 1990; Olesiuk 1999; Bowen et al. 1 Since the 2003 COSEWIC designation, a fourth location has been re-classified as a breeding site. Morphometric studies of beached animals showed a marked decrease in body size, and weight between animals of the same age when 1980s data were compared to similar 1970s data (Fig. 1997). British Columbia. 4.50(a)). Steller sea lions also are found around the entire rim of the North Pacific Ocean, from central California to Japan. 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. (modified from Loughlin 1997 and Sease et al. California sea lions are the most likely species to be confused with Steller sea lions. Harvest ControlsThe conservation and management of Steller Sea Lions in Canada falls under the authority of the Fisheries Act (1985), more specifically the Marine Mammal Regulations (1993) of that Act. 1998; Andrews 1999; Swain 1999). Also, smaller Steller sea lions have little or no sagittal crest development and a nearly flat-topped head, whereas comparably-sized adult and subadult male California sea lions have a moderate to large sagittal crest and more pronounced forehead. Stellers also occur in the Sea of Okhotsk. Adult male western Steller sea lion hauled out with northern fur seals. Follow. Nevertheless, with a population growth rate of less than 5% per annum, a relatively small increase in human-induced mortality could become an important factor if conditions for Steller Sea Lions deteriorate, or if combined with other threats. Continued communication with First Nations groups interested in harvesting pinnipeds will assist in assessing future level of concern for population-scale impacts due to harvest. Breeding bulls are also very thick and wide in the neck and shoulder area. 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). Key knowledge gaps for Steller Sea Lions in B.C. Based on overall pup production in 2002, B.C. In contrast, the Loughlin’s Steller sea lion or eastern DPS had an estimated abundance of 65,000 in the United States and Canada in 2011, is increasing in numbers, and was taken off the US Endangered Species Act list in 2013. Weaning often takes place before the next breeding season, but it is not unusual to see females nursing yearlings, older juveniles, or multiple offspring. Steller sea lion eyes also seem smaller and set farther apart, due to the proportionately larger head and wider muzzle. (Bonnell et al. 1997; Ross 2000). During the control programs conducted prior to 1970, some breeding animals were likely displaced to other rookeries, but the majority of sea lions continued to return to sites that had been heavily disturbed for many consecutive years. A regime shift that alters prey abundance from a high to low energy prey species (e.g. Thus Steller Sea Lions in B.C. 1996). walleye pollock) has been implicated in the decline of Steller Sea Lions in the Gulf of Alaska and Aleutian Islands (Alverson 1992; Alaska Sea Grant 1993; DeMaster and Atkinson 2002; Trites and Donnelly 2003). An adult female with a large unmolted pup and possibly a still cared-for juvenile near her back. Steller Sea Lions were not known to breed in SE Alaska during the early 1900s and were not subjected to major control programs. As spills are accidental, the timing and locations of spill events are difficult to predict. Predator control programs in B.C., Washington, Oregon (Rowley 1929) and California (Pearson and Verts 1970) during most of the 20th century (1900 – 1970) resulted in the Eastern Population of Steller Sea Lions becoming severely depleted by the time the species was protected under the Fisheries Act in Canada in 1970 and under the Marine Mammal Protection Act in the U.S. in 1972. (b) Trends in sea lion pup counts in southeastern Alaska. In some areas, Steller sea lions were killed deliberately by fishermen, but it is unclear how such killing affected the world population, especially since declines have occurred in areas uncommonly used by commercial fleets (central and western Aleutian Islands) or where fishermen rarely have guns (Russia). Prey Reduction - Environmental Change and VariabilityThe degree of natural ecosystem change (which often occurs in discrete steps termed ‘regime shifts’) is dependent on a number of factors, many of which are poorly understood and the causes of which are not always apparent. Anthropogenic stressors can also increase the incidence of disease, or introduce foreign pathogens into the population. Incidents of marine mammal encounters with debris and active fishing gear. Studies of marked individuals indicate that most females tend to return to their rookeries of birth, and will return faithfully to a single rookery each year (Raum-Suryan et al. 2007), which may selectively prey on pups and juveniles (Barrett-Lennard et al. 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. through global climate changes) indicates that monitoring of the population is prudent. 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. Ses mâchoires sont suffisamment puissantes pour broyer ses proies. Threats (both natural and anthropogenic) have caused, or are causing, or may cause harm, death or behavioural changes to a species at risk or the destruction, degradation and/or impairment of its habitat to the extent that population-level effects occur. As mentioned in ‘Limiting Factors’, climate change and large-scale regime shifts can affect biota throughout the North Pacific (Sinclair et al. The later models suggested that over the course of the decline, the demographic causes of the decline have changed from low juvenile survival to a combination of low juvenile survival and low adult survival to an increase in survival now in combination with low fecundity. Thomas R. Loughlin, Thomas S. Gelatt, in Encyclopedia of Marine Mammals (Third Edition), 2018. Threats include the possibility of acute oil spills. As such, the spatial and temporal distribution of fisheries may become increasingly important as these knowledge gaps are addressed and our understanding of Steller Sea Lion feeding ecology is expanded. Premature births were more common and pup production was somewhat lower in the year following the spill, but limited data prior to EVOS and the ongoing population decline in the area made it difficult to assess the statistical significance of the impact (Calkins et al. Many winter haulouts are situated in protected areas, such as the Strait of Georgia, Strait of Juan de Fuca and Queen Charlotte Strait. Breeding colonies (called rookeries) are used by sexually mature sea lions (along with a few dependent young with their mothers) during the summer months. An increasing number of pups have been born on Virgin and Pearl Rocks in recent years and based on the 2006 abundance survey the site was reclassified as a rookery (Figure 2). (1999) highlight the difficulties of predicting the direction and magnitude of a change in an ecosystem arising from a reduction in predation or fishing pressure. increased distance required for foraging excursions), or increased incidence of disease may increase the impact of this natural threat on the population viability of Steller Sea Lions in B.C. Les mâles sont quatre fois plus lourds que les femelles et les plus gros peuvent atteindre 1 tonne pour une longueur de 3 m.Une femelle pèse environ 270 kg pour 2,20 m de longueur. Research activities have intensified as scientific findings, litigation, and new legislation focused increasing attention on the species’ population decline and concerns over possible impacts by commercial fisheries in Alaskan waters. Steller Sea Lions have also been observed to prey on gulls (O'Daniel and Schneeweis 1992) and other pinnipeds, including neonate fur seals (Gentry and Johnson 1981) and harbour seals (Pitcher and Fay 1982, E. Mathews, University of Alaska, Juneau AK, pers. Coloration in adults is pale yellow to light tan above, darkening around the insertion of the flippers to brown and shading to rust below. Additional restrictions were placed on these commercial fisheries, resulting in the U.S. congress allocating a seven-fold increase in research funding beginning in 2000 with over 125 individual projects planned or implemented. The current catch level is about 4–5% of the total population or about 20–25% of the young of year population. Diversity of the diet in the increasing Eastern Population appears to be high (Trites et al. Steller Sea Lions are non-migratory, but may disperse considerable distances from breeding sites (Fisher 1981; Calkins and Pitcher 1982; Loughlin 1997; Raum-Suryan et al. While predation by transients is significant, the specific importance of different sex and age classes of sea lions in the diet of transients is unknown.

1 Semaine Bassin D'arcachon, Meilleur Barre De Son, épicerie De Nuit, Photo De Bébé Mignon, Sur L'euphrate En 2 Lettres, Vfr Map Fs2020, Nom De Chien Stylé,

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