Limited commercial harvests were also conducted for hides and for mink food. 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). 2007; Burkanov and Loughlin 2007). However, the perception that the unexplained portion of the decline of the Western Stock began in the eastern Aleutians may be colored somewhat by changes that likely resulted from the massive harvests of pups (the entire annual production for three straight years) and associated disturbance of adults at the largest of the rookeries in that region in 1970–1972. Entanglement in derelict gear is rare and unlikely to have contributed to the decline. Steller Sea Lions also congregate in estuaries during autumn to feed on pre-spawning salmon and at the mouth of the Fraser River in spring when Eulachon are running (Bigg 1985; Bigg et al. Predation by Killer WhalesAs outlined in ‘Limiting Factors’, killer whales are an important predator having the potential to limit Steller Sea Lion populations. In addition, effects may not be notable until a stressful co-factor is implicated, such as a fasting period or period of food shortage which may increase the mobilization of fat-soluble chemicals or add to the stress upon the immune system (Jepson et al. Steller Sea Lions also occasionally venture into freshwater (Jameson and Kenyon 1977; Roffe and Mate 1984; Beachet al. The western subspecies occurs west of Cape Suckling; its common name remains the Steller sea lion. 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. British Columbia. 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. Andrey Narchuk Asia Kamchatka marine mammals ocean Pacific Pacific ocean Russia sea sea lion Steller sea lion underwater. 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. British Columbia, Canada. Asterisk (*) denotes naturally occurring threats to the population (i.e. 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. Mitigation of this threat requires outreach and communication with affected parties, and education on modification of some practices (e.g. Further genetic samples of the population within B.C. Its latin name is Eumetopias jubatus. Resolution of the question of cause has become the focus of intensive political interest because of the potential economic consequences. Mothers nurse their pups on shore for about one week, before leaving on regular feeding trips that alternate one day at sea and one day on shore (Swain 1996). Breeding colonies (called rookeries) are used by sexually mature sea lions (along with a few dependent young with their mothers) during the summer months. The question as to whether top-down forcing as a result of predation by Transient Killer Whales could also limit sea lion populations has garnered much attention in recent years. 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. 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. Steller Sea Lions also compete with other marine predators, including other species of pinnipeds, whales, seabirds, sharks and flatfish (Livingston 1991; Tamura and Ohsumi 2000; Wespestad et al. 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. British Columbia. 1990; Olesiuk 1999; Bowen et al. 1985). 2000; Benson and Trites 2002), and such changes may affect Steller Sea Lion prey distribution within B.C. Forrester Island accounted for much of the growth until the early 1980s, but its growth rate has subsequently slowed, and newly established rookeries in central-northern SE Alaska as well as other rookeries in B.C. Taxonomically the species belongs to the Order Carnivora, Suborder Pinnipedia, and Family Otariidae. The offshore distribution of Steller Sea Lions is not well defined. C'est la seule espèce du genre Eumetopias. After 1918, the harvest was conducted under the auspices of the Treaty on the Conservation of the Northern Fur Seal (see Northern Fur Seal). Over 50 species of fish and invertebrates have been identified in the diets of Steller Sea Lions (Wilke and Kenyon 1952; Pike 1958; Spalding 1964; Pitcher 1981; Kastelein et al. 2004). These include the flame retardant PBDEs, which are doubling every four years in the environment (Hites 2004; Ross 2006). The vibrissae are pale, conspicuous, and long. Steller Sea Lions can also rest in the water during storms or heavy swells when haulouts are awash, or when they are near concentrations of prey without suitable nearby haulouts; this rafting behaviour often occurs in groups (Kenyon and Rice 1961; Olesiuk and Bigg 1988). steller's eider. Therefore the importance of targeted research programs addressing knowledge gaps, and long-term monitoring of the population and of identified threats cannot be overemphasized. Robert B. Males also have larger canines that are both longer and thicker than those of females. As uncertainties on the level of toxic loading in Steller Sea Lions in B.C. California sea lions are the most likely species to be confused with Steller sea lions. Given that mitigation measures for predator-prey interactions are extremely unlikely, monitoring of both the Steller Sea Lion and Transient Killer Whale populations will assist in determining long-term trends in abundance and distribution of both of these species within B.C., and range-wide. (2007) extended this model by additionally using counts of pups and an index of the number of juveniles developed from photographs using pup counts. There is a small opening in the skin at the end of each digit for a claw that is usually reduced to a vestigial nodule, and rarely emerges above the skin. Although the Western Stock was formerly the largest stock by far, with about 170,000 individuals in the mid-1970s, it is just 30,000–40,000 today and was listed as “Endangered” under the Endangered Species Act in 1997. Beginning in the late 1990s, numbers may even have increased slightly at some rookeries in the GOA. 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. Use of sea lions by First Nations people appears to have declined during the 1800s and sea lion meat has not been an important dietary staple since the early 1900s (Bigg 1985). ), but disturbance of rookeries may persist over a number of years (Olesiuk, unpublished data). French. Adult females (cows) are noticeably smaller, averaging 2.2 m and 200-300 kg (Mathisenet al.. 1962; Thorsteinson and Lensink 1962; Orr and Poulter 1967; Winshipet al.. 2001). 2000; Benson and Trites 2002; Fritz and Hinkley 2005; Trites et al. 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 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. English. This pattern was observed for four virus serotypes (Barlough et al., 1987). The population is currently thought to be stable overall, but with significant variation in trends among locations within the range of the population. comm.). had been reduced to 4,550 by 1961 and 3,390 animals (including 940 pups) by the time the first aerial survey was conducted in 1971. In some cases, levels of persistent environmental contaminants have been associated with adverse health effects in free-ranging pinnipeds. 1997, 2003; Raum-Suryan et al. dumping offal, habituation of animals to fishing gear), and increased monitoring and enforcement around Steller Sea Lion haulouts and rookeries. Total abundance in the United States and Russia of this subspecies was estimated to be 78,000 in 2011. 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. Disturbance on and around Terrestrial HabitatRepeated disturbances of breeding or haulout sites by aircraft, boats, pedestrians, construction, or fishing activities (e.g. 1983; Merrick and Loughlin 1997). Further research may be necessary to address knowledge gaps on the rate of entanglements and their effect on a population-wide scale. The effects of threats are often difficult to distinguish from one another, or from natural limiting factors. Furthermore, the Statement of Canadian Practice with respect to the Mitigation of Seismic Sound in the Marine Environment was developed as a national code of conduct in response to public concerns over the potential impacts of seismic surveys on marine life. The western population declined by approximately 57% between 1981 to 2011, most severely (–81%) in the large populations from the Gulf of Alaska, west throughout the Aleutian Islands to Russia. The potential for altering predation rate by killer whales due to environmental variability, changes in prey availability (i.e. You will not receive a reply. are also protected within National or Provincial Parks, such as Pacific Rim and Gulf Islands National Park Reserves, Race Rocks Ecological Reserve, and others. Juveniles are darker than adults and are dark tan to light brown. Females returning from foraging trips vocalize to find and attract their pup. Bioenergetic models predict that daily food requirements for Steller Sea Lions in the wild are approximately 15-20 kg for mature females and 30-35 kg for mature males (Winship et al. An adult male Loughlin’s Steller sea lion on with a juvenile California sea lion in southern California. Steller Sea Lions can dive to depths of at least 310 m (Andrews 1999) and stay submerged for over 8 minutes (Swain and Calkins 1997), with most dives in the range of 15-50 m and lasting 1.5-2.5 min (Merrick and Loughlin 1997; Swain and Calkins 1997; Loughlin et al. English: Steller Sea Lion español: León marino de Steller français: Lion de mer de Steller 日本語: トド属 Simulation models have shown that Transient Killer Whales could potentially have a significant impact on Steller Sea Lion populations, and in particular could inhibit the recovery of depleted populations (Barrett-Lennard et al. The population decline in the Aleutian Is. 1998; see review by Trites and Donnelly 2003), and prey requirements will continue to increase as the Eastern population continues to grow. Because nursing females are restricted to foraging within commuting distance of rookeries during the first few months after giving birth, prey availability around rookeries may be critical in ensuring successful early survival of pups and their nursing mothers. Taxonomic information Carnivora, Otariidae. Successful males will usually maintain their territory for an average of 40 days (range 20-68 days) without feeding (Gentry 1970). Key knowledge gaps for Steller Sea Lions in B.C. The maximum productivity level has not been determined for this species, but it is likely low. Further, management of sources of outflow and runoff may assist in mitigating this threat. In B.C., sea lions are occasionally seen rafting as far as 35 km upriver (Olesiuk, unpublished data). First Nations HarvestTraditionally, Steller Sea Lions were hunted by aboriginal peoples in B.C. 1996). Several viability analyses have been applied to Steller's sea lion population data. Figure 1: Worldwide Range of the Steller Sea Lion. The current catches in Canada have averaged 312,000 for the past 5 years. Values for the central and western GOA are proportional annual means (±SE) of counts made during late June to July at the rookeries Clubbing Rock, Pinnacle Rock, Chernabura Is., Atkins Is., Chowiet Is., Chirikof Is., Marmot Is., Sugarloaf Is., Outer Pye Is., and Chiswell Is. Steller sea lions breed in the late spring and summer. Information from voluntary reporting between 2004 and 2008 indicates only one animal was positively identified as a Steller Sea Lion (drowned as a result of entrapment) and another 12 pinnipeds could not be identified to species2. Due to the recent declines in Alaska, the British Columbia rookeries at the Scott Islands and Cape St. James now represent the second and sixth largest breeding aggregations in the world. They appear to feed over the continental shelf and along the shelf break (Kajimura and Loughlin 1988). A Eumetopias jubatus rookery with adult females and males. Common Name (population): Steller Sea LionScientific Name: Eumetopias jubatus, Reason for Designation: There are only three1 breeding locations in British Columbia. The principle cause of death for pups is drowning due to limited swimming abilities at this age preventing them from hauling out of the water or steering in strong tidal currents (Orr and Poulter 1967; Edie 1977). 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. Stellers have deep voices and produce powerful low-frequency rolling roars that can be heard for long distances over the noise of wind and waves. Mitigation potential refers to the likelihood that measures (future or existing) may mitigate or prevent negative effects to the population. Captive feeding studies of harbour seals have also demonstrated deleterious effects of persistent contaminants on the reproductive, immune and endocrine systems (Brouwer et al.. 1989; de Swart et al.. 1994; Ross et al. The Steller Sea Lion is the largest species of otariid and the only one that resides and breeds year-round in Canadian waters. The population model takes into account catches in Canada and Greenland, bycatch in fishing gear and animals struck and lost in the harvests. Steller Sea Lions are widely perceived to be an important component of the coastal marine ecosystem, and contribute to the eco-tourism industry. These reserves were established in 1971 by the Province of British Columbia to protect biodiversity. Information to assist enforcement and response to incidents is collected by the Marine Mammal Response Program (1-800-465-4336). 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). 1996; Anderson et al. 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. 453-457. Steller sea lions are named for Georg Wilhelm Steller, the German surgeon and naturalist on the Bering expedition who first described and wrote about the species in 1742. 1998) provides further evidence of nutritional stress during the steep declines in the Western Population observed during the 1980s (NMFS 2008). A juvenile that still has a lot of growing-up to do. for predator control or subsistence harvest). date back to the early 1900s, and provide an index of the size of the Canadian breeding population (Bigg 1984, 1985; DFO 2008). has averaged about 185 million kg over the last decade (DFO 2007). 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. Distribution Steller sea lions are found from central California (formerly southern California), north to the Aleutian Islands, and west along the Aleutian chain to Kamchatka, and from there south along the Kuril Islands to northern Japan, the Sea of Japan, and Korea. However, debate continues over the relative influence of fluctuations in environmental conditions and regime shifts that may be the result of global warming, as well as the effects of whaling and commercial fisheries (Pascual and Adkinson 1994; Fritz and Ferrero 1998; Pauly et al. They are not considered migratory, and juveniles and subadults make most long distance trips. lUCN status Near Threatened overall. Of 31 females branded as pups on Forrester Island, several were observed to have given birth at other rookeries, including 400 km away at Cape St. James (Raum-Suryan and Pitcher 2000; Raum-Suryan et al. BrownellJr., in Encyclopedia of Biodiversity (Second Edition), 2013. The main threat is likely through contact with heavy oil accumulations when the source of the spill is near important habitats such as rookeries and haulout sites, and to a lesser degree from absorption through the skin, incidental ingestion of oil directly or through feeding, exposure to vapours, and partial fouling of pelage from fresh oil (Smith and Geraci 1975; Engelhardt et al. 2002). In comparison, the total annual commercial fish landing in B.C. 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). Abundance in Canadian waters was estimated to be 20,000-28,000 based on the most recent survey in 2006 (DFO 2008). Targeted enforcement of disturbance is focusing on whale oriented viewing, but also addresses the disturbance of pinnipeds, especially when hauled out near populated areas. PCB, dioxins, furans and organochlorine pesticides are considered to be regulated, ‘legacy’ contaminants as a result of national and international restrictions on their use, production and/or by-production. The marine debris documented to cause entanglements results mainly from lost fishing gear. However, the results of modeling studies indicate that the observed sea lion population decline cannot be explained solely through trophic interactions, and rather is more likely linked to inadequate recruitment and shifts in environmental conditions which lead to changes in the favored complex of species (DeMaster and Atkinson, 2002; Cornick et al., 2006; Fay and Punt, 2006). It accelerated rapidly to nearly 16% per year during the second half of the 1980s, when as many as 8000–25,000 animals disappeared from the population each year, before dropping to just over 5% per year throughout the 1990s (Paine et al., 2003). and consume the same prey species (Olesiuk and Bigg 1988). Status re-examined and designated special concern in November 2003. Longevity is 20 years in males and up to 30 years in females. Large sharks may also prey on Steller Sea Lions in the southern part of their range (Stroud 1978; Ainley et al. 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). Several large female western Steller sea lions surrounded by juveniles in the Aleutian Islands. 1990; Sinclair and Zeppelin 2002). Section 1.5.2 provides detailed descriptions of twelve historic, current and potential threats to the Steller Sea Lion population in B.C., as well as the uncertainties surrounding population level effects. The reasons for the decline and continuing low numbers of western animals are still unclear, and the subject of ongoing research. Updated from Bigg (1985) (DFO unpublished data). Careful attention to head and muzzle size and shape, overall coloration, and length and width of fore- and hindflippers permits separation. (Table 1). 1999; Rosen and Trites 2000a; Shima et al. Regime Shift)*, Un-regulated Persistent Organic Pollutants (POPs), Physical disturbance when on terrestrial habitat, Acoustic disturbance when in aquatic habitat, Habitat use (i.e. The vernacular name for this subspecies is Loughlin’s northern sea lion. York (1994) using two age-structure samples with their estimated survival and fecundity rates and counts of Steller sea lions from aerial surveys suggested that the early decline was mostly caused by a decline in juvenile survival. 1998). Several natural limiting factors are currently poorly understood. 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. 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. 1984; Loughlin et al. rookeries, although increasing numbers of animals have recently begun breeding on the gravel beaches along the eastern (leeward) side of Triangle Island (Olesiuk, unpublished data). However, calicivirus activity among reproducing females was seen (Barlough et al., 1987). Increasing knowledge of the seasonal distribution of Transient Killer Whales and their diet will assist in determining the degree to which predation regulates Steller sea lion population growth in B.C. 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. The direct and incidental killing of sea lions in the 1950s through the first half of the 1980s (described in Section 3.5) likely had effects on local abundances, but in the mid-1970s the Western Stock was considered to be at or near the pre-exploitation level of abundance (Interagency Task Group, 1978). 1986; Ross et al. constituted one of the largest known sources of human-induced mortality for Steller Sea Lions in the North Pacific (Angliss et al. 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. Females begin returning to rookeries in late May and give birth to a single pup within a few days of their arrival; most pups are born by early July (Gentry 1970; Edie 1977; Bigg 1985). Consideration for the placement of industrial developments near rookeries should assist in mitigation of this potential chronic threat. Adult males add a considerable amount of weight in late winter and spring, before the summer breeding season, and slim down afterwards. Steller Sea Lions inhabit the cool-temperate and subarctic coastal waters of the North Pacific Ocean from the Channel Islands off southern California, north to the Bering Strait, and southwest along the Asian coast to Hokkaido, Japan (Fig.