Weaning often takes place before the next breeding season, but it is not unusual to see females nursing yearlings, older juveniles, or multiple offspring. Adult animals are lighter in color than most sea lions, ranging from pale yellow to tawny and occasionally reddish.

Contaminants , 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. View critical habitat maps for Steller sea lions: In December 2017, NOAA Fisheries initiated a 5-year status review of the endangered western DPS of Steller sea lion under the ESA. The Northwest Atlantic harp seal (Pagophilus groenlandicus) population in Canada and Greenland is currently subject to a harvest.

Aside from food and clothing, their skin was used to cover baidarkas and kayaks. Literature also suggests that some protected zones may also have long-term positive impacts on ecosystem function. Amendments to the Marine Mammal Protection Act 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 marine mammal stock assessments for the western and eastern DPSs. ) From lavage to lipids: estimating diets of seabirds.

In this way, a much more intense mixing of infected seals and potentially infected reservoirs along the near-shore feeding zones can take place, resulting in a high incidence of exposure for all susceptible individuals in the population regardless of sex or age class. Endangered Species Act. Sea lion groups in other areas of Alaska are not endangered, but there is something going on with sea lions in the western end of the Aleutian arc, near Attu, Shemya and Buldir islands. After 1918, the harvest was conducted under the auspices of the Treaty on the Conservation of the Northern Fur Seal (see Northern Fur Seal). [22][23] A week or so later, adult females arrive, accompanied occasionally by sexually immature offspring, and form fluid aggregations throughout the rookery.
The US National Marine Fisheries Service considers the species to be monotypic, managing it as western and eastern stocks, referred to as Distinct Populations Segments. Steller sea lions are skilled and opportunistic marine predators, feeding on a wide range of fish and cephalopod species. [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. Decadal scale regime shifts, and shorter-term oceanographic anomalies such as  El Niño Southern Oscillation (ENSO) events and marine heatwaves, also can have large effects on distribution and abundance of Steller sea lion prey. Females usually mate within 2 weeks after giving birth. 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.

In body mass they are the largest of the world's otariids, with males averaging 1000 kg. The range of the Steller sea lion extends from the Kuril Islands in the Sea of Okhotsk in Russia to the Gulf of Alaska in the north, down to Año Nuevo Island off the coast of central California to the south. High-resolution serial sampling for nitrogen stable isotope analysis of archaeological mammal teeth. 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. Steller sea lions are exposed to a variety of diseases and parasites. They are found in the Columbia River nearly year round,[40] with the exception of early summer, going as far upstream as Bonneville Dam. The western DPS includes all Steller sea lions originating from rookeries west of Cape Suckling (144° west longitude). Different individuals may have different foraging strategies. Photo: Alaska Department of Fish and Game. NOAA Fisheries published the first  recovery plan for the Steller sea lion in 1992.

NOAA Fisheries has issued two incidental harassment authorizations to the U.S. Navy to incidentally harass, by Level A and Level B harassment only, marine mammals during construction activities associated with the Transit Protection Program Pier and…, NOAA Fisheries has issued an incidental harassment authorization (IHA) to the Lamont-Doherty Earth Observatory of Columbia University (L-DEO) to incidentally harass marine mammals during a marine geophysical survey in the Aleutian Islands, Alaska. [34], Like most otariids, Steller sea lions are vocal in air. The Steller sea lions’ range overlaps with the California sea lion (Zalophus californianus), but these two species are easily distinguished; the latter is darker and smaller. Sandergen, F. E. (1970).

Typical for adult female Steller sea lions, this western adult lacks the enlarged chest and neck of bulls. Both sexes become blonder with age. Either one or perhaps all three mechanisms of virus survival are operating within the ecosystem inhabited by Steller sea lions and may have contributed to the protracted decline of some Steller sea lion populations, which began subsequent to the mid-1970s. The sexual dimorphism of Steller sea lions, and the fact that they may climb up on rocks or cliff faces on some sites, both increase their risk of injury or death if they are disturbed. [14] Typically, Stellar sea lions spend their time in the water feeding but haul-out onto land to reproduce, raise their pups, molt, and rest. Sites where animals haul-out to rest, where breeding does not occur, are referred to as haulouts. [50], Olesiuk, Peter F, and Bigg, Michael A. Note the sexual dimorphism between the larger males and the smaller females.

The species is named for the naturalist Georg Wilhelm Steller, who first described them in 1741. The cause or causes of long-term decline in the western population of Steller's sea lions are not understood. [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. Those areas may be designated as critical habitat through a rulemaking process. Both males and females also produce underwater noises similar to their above water sounds, described as clicks, barks, and belches. While the populations of the eastern and Asian stocks appear stable, the population of the western stock, particularly along the Aleutian Islands, was estimated to have fallen by 70–80% since the 1970s.

Adult animals are lighter in color than most sea lions, ranging from pale yellow to tawny and occasionally reddish. [citation needed]. The disease effects of abortion, stunting of offspring, and agalactia (lack of or dramatically reduced milk production) are well documented for calicivirus infections in some species (Smith and Boyt, 1990), and these same effects would be expected in Steller sea lions, where their occurrence could contribute substantially to population decline. Cumulative and annual commercial fishery removals may result in temporal and seasonal changes in distribution and abundance of primary prey, prey reduction, and  changes in prey size; they may also cause ecosystem effects.

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