|Scientific Name:||Mirounga leonina (Linnaeus, 1758)|
Phoca leonina Linnaeus, 1758
|Taxonomic Notes:||The two species of Elephant Seals, Mirounga leonina and M. angustirostris, share many similarities in appearance and behaviour and differ primarily in their range and in the timing of their terrestrial periods ashore (Bonner 1989, Ling and Bryden 1992). Speciation is thought to have occurred approximately one million years ago (Hoelzel et al. 1993).|
|Red List Category & Criteria:||Least Concern ver 3.1|
|Facilitator/Compiler(s):||Lowry, L., Ahonen, H., Pollock, C.M., Chiozza, F. & Battistoni, A.|
Estimates of Southern Elephant Seal abundance indicate a global pup production of over 200,000 at some 15 islands or island groups. However recent estimates are lacking, including for the largest subpopulation. Global abundance is inferred to have been stable or to have increased over the past three generations. While 50% of pup production is estimated to take place at South Georgia, four other sites each support more than 5% of global pup production. Three of those sites have experienced decreases over the past three generations that are not fully understood. While decreases have ceased at two of these sites, they continue at a third. In the light of the unknown effects of global climate change on this species, and the age of estimates of abundance for some subpopulations, demographic monitoring is imperative. This species continues to qualify for listing by IUCN as Least Concern.
|Previously published Red List assessments:|
|Range Description:||Southern Elephant Seals have a nearly circumpolar distribution in the Southern Ocean. While most haulout sites are on Subantarctic and Antarctic islands, a number of animals haul out regularly at sites on the coasts of southern Argentina and Chile (Campagna and Lewis 1992) and Antarctica (Bester 1988, Heimark and Heimark 1986, Murray 1981). They forage at sea between about 40° south and the Antarctic Continent. Occasional vagrants have been recorded on the coasts of northern South America (Alava and Carvajal 2005, De Moura et al. 2010), southern Africa (Kettlewell and Rand 1955, Oosthuizen et al. 1988), Australia and New Zealand (Mills et al. 1977, Taylor and Taylor 1989). The most distant vagrant was recorded at Oman on the Arabian Peninsula, some 9,000 km from the nearest possible point of origin (Johnson 1990).|
Native:Antarctica; Argentina; Australia (Macquarie Is., New South Wales - Vagrant, South Australia - Vagrant, Tasmania - Vagrant, Victoria - Vagrant, Western Australia - Vagrant); Bouvet Island; Chile (Juan Fernández Is. - Vagrant); Falkland Islands (Malvinas); French Southern Territories (Crozet Is., Kerguelen); Heard Island and McDonald Islands; New Zealand (Antipodean Is., Chatham Is. - Vagrant, North Is. - Vagrant, South Is. - Vagrant); Saint Helena, Ascension and Tristan da Cunha (Saint Helena (main island) - Vagrant, Tristan da Cunha); South Georgia and the South Sandwich Islands
Vagrant:Angola; Brazil; Ecuador; Mauritius; Mozambique; Namibia; Oman; Peru; South Africa (Eastern Cape Province, KwaZulu-Natal, Marion-Prince Edward Is. - Native, Northern Cape Province, Western Cape); Uruguay
|FAO Marine Fishing Areas:|
Atlantic – Antarctic; Atlantic – southwest; Atlantic – southeast; Indian Ocean – Antarctic; Indian Ocean – western; Indian Ocean – eastern; Pacific – Antarctic; Pacific – southwest; Pacific – southeast
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||No recent comprehensive estimate of Southern Elephant Seal abundance is available throughout the entire distribution. The worldwide population was estimated to be 650,000 in the mid 1990s (SCAR EGS 2008). Four distinct populations have been identified in the Southern Ocean (Gales et al. 1989, Hoelzel et al. 1993, Slade et al. 1998). While the movement of breeding individuals between these populations is rare, it does occur (Fabiani et al. 2003, Reisinger and Bester 2010). These populations include subpopulations at or close to Argentina (Peninsula Valdés and the Falkland Islands), in the Atlantic sector (South Georgia, South Orkney Islands, South Shetland Islands, Bouvetøya and Gough Island), in the Indian sector (Iles Kerguelen, Iles Crozet, Heard Island and the Prince Edward Islands) and in the Pacific sector (Macquarie Island, Campbell Island and Antipodes Island). A further four historical populations are extinct, likely due to exploitation: St. Helena Island, Tristan da Cunha, Islas Juan Fernández and the Bass Strait (Bester 1980, Carrick and Ingham 1962, Wace and Holdgate 1976). A subpopulation from Victoria Land on the Antarctic coast became extinct a few hundred years prior to human discovery (Hall et al. 2006).|
While Southern Elephant Seals breed at 14 islands or island groups, five of these are responsible for 99% of pup production. More than 50% of pup production takes place at South Georgia (Boyd et al. 1996, M. Fedak pers. comm. in SCAR EGS 2008), with Isle Kerguelen responsible for some 21% (Authier et al. 2011) and the Peninsula Valdes, Heard Island and Macquarie Island each responsible for greater than 5% (Lewis et al. 1998, Slip and Burton 1999, van den Hoff et al. 2014).
The Peninsula Valdes/Falkland Island colonies have increased in recent times (Lewis et al. 1998, Galimberti et al. 2001, SCAR EGS 2008). Colonies in the Atlantic sector of the Southern Ocean are also growing or stable (Boyd et al. 1996, Galimberti et al. 2001, SCAR EGS 2008, Gil-Delgado et al. 2013). In contrast, those in the Indian Ocean (Guinet et al. 1999, Slip and Burton 1999, Pistorius et al. 2004, Bester and Hofmeyr 2005, de Bruyn 2009, Pistorius et al. 2011) and Pacific Ocean (van den Hoff et al. 2007, 2014) sectors have been either stable or decreasing to the mid 1990s. However, recent cessations of decrease, and increases, have been recorded at island groups in the Indian Ocean sector (McMahon et al. 2009, Authier et al. 2011, Pistorius et al. 2011). This is not true for the Macquarie Island subpopulation, the only substantial population within the Pacific sector (van den Hoff et al. 2014). Numbers of adult females in this subpopulation declined at a mean annual rate of -0.8% between 1988 and 2011, and continued to do so through 2014.
The causes of these declines are debated. They are not completely understood and may differ between populations but evidence indicates that the low survival of adult females (Pistorius et al. 2004, de Bruyn 2009, Pistorius et al. 2011, van den Hoff et al. 2014) or of pups (McMahon and Burton 2005, McMahon et al. 2005ab) is important. Survival of both adult females (Pistorius et al. 2011, van den Hoff et al. 2014) and pups (McMahon and Burton 2005, McMahon et al. 2005b) varies interannually with climatic conditions. The low survival of adult females may be due to the effects of the limitation of food on an age and sex class that is responsible for successfully weaning offspring, and migrating to distant foraging grounds to recover from terrestrial fasts (Pistorius et al. 2011, van den Hoff et al. 2014) whereas the low survival of pups may be due to low weaning mass and also reduced food availability to naïve, and therefore vulnerable, animals (McMahon et al. 2003, 2005a).
Generation length has been calculated at 9.5 years (Pacifici et al. 2013). Population change over three generations from 1982–2009 is inferred to have been stable or positive (SCAR EGS 2008, Authier 2011, Pistorius et al. 2011, van den Hoff 2014).
|Current Population Trend:||Stable|
|Habitat and Ecology:||Southern Elephant Seals are the largest of all pinnipeds with adult males reaching masses of two to four tons and lengths of up to 4.5 m. They show considerable sexual dimorphism, with adult females only reaching masses of 400-900 kg and average lengths of 2.8 m. Newborn pups weigh between 40 and 46 kg (Laws 1993). Females first haul out to pup at ages of three to six years, and males typically breed for the first time at six to ten years of age (Laws 1956, Carrick et al. 1962a, Jones 1981, McCann 1981, Pistorius et al. 2001, Kirkman et al. 2004). At Marion Island, less than 5% of females survived beyond 13 years of age, and less than 5% of males beyond 10 years of age (de Bruyn 2009). Longevity of 23 years has been recorded for adult females at Macquarie Island (Hindell and Little 1988).|
Southern Elephant Seals undergo an annual double migration between foraging grounds and isolated haulout sites, at which they are born and where they breed in the austral spring, moult in the austral summer, and as immatures haulout in the winter (Bartholomew and Hubbs 1960, Carrick et al. 1962b, Hindell and Burton 1988). Southern Elephant Seals are predominantly marine. Adult females spend more than 85% of each year at sea while adult males spend less than 80% (Carrick et al. 1962a, Hindell and Burton 1988, McIntyre et al. 2010). Their foraging grounds may be located over 5,000 km from their terrestrial haulout sites (Bester and Pansegrouw 1992, Jonker and Bester 1998, Campagna et al. 1999, Bailleul et al. 2007).
Southern Elephant Seals spend most of their at-sea time foraging in association with frontal systems, currents and shifting marginal ice-edge zones. Studies of foraging sites suggest that they are sensitive to fine-scale variation in bathymetry and ocean properties (sea-ice concentration and sea temperature profiles) (Bailleul et al. 2007, Biuw et al. 2010). Southern Elephant Seals are prodigious divers. Dive depth and duration vary during the year and between the sexes, but mostly range from 200 to 700 m deep and from 20 to just over 30 minutes in duration (Biuw et al. 2010, McIntyre et al. 2010). Both sexes spend over 65% of their lives below 100 m. The maximum record dive depth is 2,133 m for an adult male (McIntyre et al. 2010).
The diet varies between populations and seasons. It consist primarily of myctophid and notothenid fish and squid (Brown et al. 1999, Piatkowski et al. 2002, Bradshaw et al. 2003, van den Hoff et al. 2003, Cherel et al. 2008, Newland et al. 2011).
Four types of terrestrial periods are experienced over the course of their lives: the breeding, moult and winter haulouts, and the natal terrestrial period. The mating system is mate-defense polygyny. Breeding seasons are highly synchronized (Carrick et al. 1962b, Laws 1956, McCann 1981, Bonner 1989). Adult females spend approximately a month ashore during the breeding season, while adult males may spend one to three months ashore. During this time adult females will haul out in large aggregations that may contain up to a thousand animals (Carrick et al. 1962a, Bonner 1989). Some three to seven days after females come ashore they give birth to a single pup, which they will suckle for some three weeks. Mating takes place shortly before the pup is weaned and the adult female returns to the sea a few days later. Breeding aggregations are ephemeral, and do not last beyond the breeding season. Access to all females in one breeding aggregation is defended by a dominant adult male. In larger breeding aggregations, subdominant males also gain access to females (Laws 1956, Carrick et al. 1962a, McCann 1981).
Killer Whales are the primary predators of Southern Elephant Seals (Reisinger et al. 2011) but Leopard Seals are also known to take pups (Gwyn 1953).
|Generation Length (years):||9.5|
|Movement patterns:||Full Migrant|
|Congregatory:||Congregatory (and dispersive)|
|Use and Trade:||Southern Elephant Seals were hunted for thousands of years by aboriginal and native peoples in Australia and South America. More recently, they were subject to intensive commercial harvests starting in the early 19th century and not ending until 1964 at South Georgia (McCann 1985). They were prized for their large quantity of blubber that could be rendered to fine, valuable oil (Laws 1960). The commercial harvesting of Southern Elephant Seals ceased in 1964 and they have not been subject to exploitation since (McCann 1985).|
Southern Elephant Seals face few threats and conflicts today, since they live far from human population centres and have minimal interactions with commercial fisheries. Intensive fishing could, however, deplete important prey stocks (Hanchet et al. 2003). The possible effects of global climate change on Southern Elephant Seals are not well known but such changes may negatively impact prey populations or change marine habitat (Learmonth et al. 2006, Kovacs et al. 2012). It is also possible that a reduction in sea ice due to climate change may benefit Southern Elephant Seals (van den Hoff et al. 2014). Southern Elephant Seals that haul out at mainland sites could come in contact with domestic and wild animals and be exposed to a variety of diseases including morbilliviruses (Lavigne and Schmitz 1990).
Any future exploitation of Southern Elephant Seals within the Antarctic Treaty area (south of 60°S) is regulated by the Convention for the Conservation of Antarctic Seals, while north of this area the Convention on Antarctic Marine Living Resources and various national measures apply to the islands and continental areas on which the species breeds and occurs. The Falkland Islands Dependencies Conservation Ordinance provides protection for Southern Elephant Seals on South Georgia and the South Sandwich Islands (Reijnders et al. 1993). Seals on the Prince Edward Islands are protected by virtue of these islands status as a special nature reserve, their location within a marine protected area, and also by the South African Seabirds and Seals Protection Act (PEIMP 2010).
|Citation:||Hofmeyr, G.J.G. 2015. Mirounga leonina. The IUCN Red List of Threatened Species 2015: e.T13583A45227247.Downloaded on 25 November 2017.|
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