Ultimately, we seek to have the species recover so the ESA’s protections are no longer needed to stave off its extinction. A second clue pointing to an infectious component came out of a statistical report of loss in fecundity and reduced birth rates over a protracted period (York, 1986). [26] After a week or so of nursing without leaving the rookery, females begin to take progressively longer and more frequent foraging trips leaving their pups behind until at some point in late summer when both the mother and pup leave the rookery together. Thomas R. Loughlin, Thomas S. Gelatt, in Encyclopedia of Marine Mammals (Third Edition), 2018.

Ecology and behavior Steller sea lions are polygynous, and breed in the late spring and summer. At sea, they are seen alone or in small groups, but may gather in large "rafts" at the surface often with their flippers held high out of the water, including areas near important seasonal prey resources. The endangered western stock of the Steller sea lion (Eumetopias jubatus) – the largest of the eared seals – has declined by 80% from population levels encountered four decades ago. The eyes are widely-spaced apart, and set well back from the end of the muzzle and, like the ear pinnae, appear small when compared with the size of the head. For the best experience, please use a modern browser such as Chrome, Firefox, or Edge. The age at weaning is highly variable; pups may remain with their mothers for as long as four years. [22] Though Steller sea lion males are generally tolerant of pups, one male filmed on Medny Island in Russia was documented killing and eating several pups in a first-ever recorded incident of cannibalism. Sandergen, F. E. (1970). Holmes and York (2003) and Holmes et al.

Adult females tend to dive deeper in winter than summer. Cape Olyutorsky, Russia. Pupping occurs from about mid-May to mid-July and peaks in June. The groundfish fisheries of the Gulf of Alaska and the Bering Sea are the most valuable and highly capitalized of the fisheries in the coastal waters of the United States. BrownellJr., in Encyclopedia of Biodiversity (Second Edition), 2013. The decline currently continues. The cause or causes of long-term decline in the western population of Steller's sea lions are not understood. They need both terrestrial and aquatic habitats. Culling and commercial harvests in Alaska (prior to  the Marine Mammal Protection Act), competition with fisheries for prey, incidental take in fisheries, entanglement, legal and illegal shooting, and possibly other factors also adversely affected Steller sea lions. A male Steller sea lion amid others on the coast of Alaska in Southeast. We are required by the…. Small pups learn to swim and begin to dive in nearshore waters near rookeries. As the pups mature, specifically at the sixth week past parturition, the mother's sea time declines by 30 percent.

The younger pups are still in their dark natal pelage. There is no relationship between the pups' activity, or physical excursion to their suckling time, age, or sex. Pre-Partum Diet of Adult Female Bearded Seals in Years of Contrasting Ice Conditions. They are known to aggregate near fishing vessels, preying on bycatch discards. This was believed to have contributed to the decline in Steller sea lions common to Alaska. 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. Using numbers of young of the year (pups) counted earlier in the century and the pattern of harvests, it was estimated that the harvests, on average, took about 30% of the number of male seals born, or about 15% of the total seals born. If they are hauled out, do not approach close enough to disturb them. More than 50% of the articles were written since 2004 with the majority pertaining to Steller sea lion life history, foraging ecology and vital rates. On land, sea lions, unlike "true" seals, can turn their hind flippers forward for walking. Steller sea lions Eumetopias jubatus (SSL), which ranges from the Gulf of Alaska to the Kuril Islands, has declined in recent decades and is currently pro- tected under the Endangered Species Act (Bickham et al.

The western DPS remains endangered. This was accomplished and the eastern DPS was delisted in late 2013. The designation of an area as critical habitat does not create a closed area, marine protected area, refuge, wilderness reserve, preservation, or other conservation area; nor does the designation affect land ownership. All aircraft need to ensure they do not disturb Steller sea lions. Trifari will take a look at specks of muscle from walleye pollock, Atka mackerel, flounder, Pacific cod, rockfish and sculpin that are waiting in a UAF freezer. [27] Reproductive males fast throughout the reproductive season,[28] often without entering the water once from mid-May until August, when the structure of the reproductive rookeries begins to fall apart and most animals leave for the open seas and disperse throughout their range. 'Breeding and Maternal Behavior of the Steller’s Sea Lion (, Haynes, Terry L. and Mishler, Craig (1991), Last edited on 21 September 2020, at 20:11, 10.2305/IUCN.UK.2016-1.RLTS.T8239A45225749.en, Alaska Marine Mammal Stock Assessments, 2009, "The oldest record of the Steller sea lion Eumetopias jubatus (Schreber, 1776) from the early Pleistocene of the North Pacific", "Annual, seasonal and daily variation in the abundance of the South American sea lion Otaria flavescens in two breeding colonies in northern Chile", "Seasonal and Spatial Differences in Diet in the Western Stock of Steller Sea Lions (, 10.1644/1545-1542(2002)083<0973:SASDID>2.0.CO;2, https://www.afsc.noaa.gov/Education/factsheets/10_SSL_FS.pdf, "Cannibal Sea Lion Kills and Eats Pup—Never Before Seen", Alaska Department of Fish and Game, "Life History", "Hydrodynamic drag in Steller sea lions (", "Turning maneuvers in Steller sea lions (Eumatopias jubatus)", "Natural History of Oregon Coast Mammals", "Fasting affects the surface and diving metabolic rates of Steller sea lions Eumetopias jubatus", "Vocal displays under water by the gray seal, the harbor seal,. Native Alaskans currently take between 150–300 a year for food and other uses. 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. . Important diet components include walleye pollock,[17][18] Atka mackerel,[17] halibut,[18] herring, capelin,[19] flatfish[19][20] Pacific cod,[17][18] rockfish,[19][20] sculpins,[19] salmon, sand lance, and cephalopods such as various squid and octopus. The cause or causes of decline in the western population of Steller's sea lions are not understood.

Possible risk factors include incidental take in fishing gear, competition with fisheries for prey in common, hunting by indigenous peoples, illegal hunting or harassment, inadvertent rookery disturbance, consumption by killer whales, disease or parasitism, contaminants, and changes in the structure and productivity in the marine ecosystems of which Steller's sea lions are part. Full-grown male Steller sea lions are heavier than the largest bull moose and can live 20 years. Their diet varies in different parts of their range and at different times of the year, depending on the abundance and distribution of prey species. 10).
NOAA Fisheries works with a variety of scientists and veterinarians to monitor disease in, Historical accounts document substantial mortality within the western DPS due to illegal shooting, especially associated with fisheries. Adult males add a considerable amount of weight in late winter and spring, before the summer breeding season, and slim down afterwards. The species is named for the naturalist Georg Wilhelm Steller, who first described them in 1741. The decline is certainly due to a complex of interrelated factors which have yet to be defined by the research effort.

Endangered for the western subspecies and Least Concern for the eastern (Loughlin’s) subspecies. The dental formula is I32,C11,PC55. [1] Killing sea lions is strictly prohibited in the US and Russia, but in Japan a fixed number are still removed annually, ostensibly to protect their fisheries. © 2020 Anchorage Daily News. 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). An adult male Loughlin’s Steller sea lion on with a juvenile California sea lion in southern California. British Columbia, Canada. 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. The relative impact of toxic substances on the recovery of the western DPS is thought to be medium, with a medium feasibility of mitigation. Two hundred or more may be taken a year in Alaska. 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). Loughlin published Using the phylogeographic method to identify Steller sea lion stocks | Find, read and cite all the research you need on ResearchGate
A Eumetopias jubatus rookery with adult females and males. Steller sea lions decreased slightly in δ 13 C and increased in δ 15 N values, suggesting an increasing trophic level and change in foraging location or oceanographic isotopic signature. Males can weigh between 450–1,120 kg (990–2,470 lb), weighing on average 544 kg (1,199 lb). Twentieth century δ The species is an important subsistence resource for Alaskan natives, who hunt sea lions for food and other uses. 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. A study done at Ano Nuevo in 1983 found that female attendance and time spent with their pup was shaped by increasing nutritional demands of the pup and the pups suckling efficiency. Entanglement in marine debris and/or ingestion of fishing gear is known to contribute to Steller sea lion injury and mortality. Steller sea lions have a massive, wide head. Those in captivity include about 8 in the United States, 12 in Canada, about 4 in Denmark, and about 15 in Japan. The Steller sea lion (Eumetopias jubatus), also known as the Steller's sea lion and northern sea lion, is a near-threatened species of sea lion in the northern Pacific. A fertilized egg may remain inside a female for up to three months before being implanted and beginning to form into a blastocyst.

Can be confused with Steller sea lions are readily separated from northern and Guadalupe fur seals that occur within their range by their massive size, large blocky head and muzzle, and pale color.

Adult male (background) and adult female (foreground) Steller sea lions, Eumetopias jubatus. [1] Killing sea lions is strictly prohibited in the US and Russia, but in Japan a fixed number are still removed annually, ostensibly to protect their fisheries. Females and males both grow rapidly until the fifth year, after which female growth slows considerably. Spies, ... Gordon H. Kruse, in Long-term Ecological Change in the Northern Gulf of Alaska, 2007.

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