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Rationale

The most recent circumpolar estimate of Leopard Seal abundance indicates a total population of more than 35,000 individuals, but this is likely a substantial underestimate. There is no indication of a declining trend in the population, although abundance estimates have considerable uncertainty around them and consequently trend is unknown. Leopard Seals depend on sea ice for reproduction and at some time in the future they could be adversely affected by a reduction in sea ice due to continued climate warming. Leopard Seals are currently a widespread and abundant species that does not qualify for any of the IUCN threatened categories, and they should be listed as Least Concern.

Distribution

Leopard Seals are widely distributed in Antarctic and sub-Antarctic waters of the Southern Hemisphere, occurring from the coast of the Antarctic continent northward throughout the pack ice and at most sub-Antarctic islands. There is a seasonal presence of juveniles at Kerguelen and Macquarie Islands with the greatest numbers being sighted in September and October (Rounseveld and Eberhard 1980, Borsa 1990). Vagrants regularly reach warm temperate latitudes. Leopard Seals haul out on ice and on land, often preferring ice floes near shore when they are available (Kooyman 1981).

Habitat View more ecological information

Population trend

Trend

The Leopard Seal is a widespread species and, similar to the other Antarctic seals that inhabit the pack ice, population assessments are very difficult and expensive to conduct and therefore undertaken infrequently. Published global population estimates from many decades ago range from 100,000â300,000 (Scheffer 1958) up to 220,000â440,000 animals (Laws 1984). However, these early estimates were based on very limited sampling and were highly speculative. An analysis of ship and aerial sighting surveys carried out around the continent between 1968 and 1983 provided a point estimate for global Leopard Seal population size in the pelagic pack ice of the Southern Ocean of 300,000 animals (Erickson and Hanson 1990). The most ambitious and coordinated effort to date, the Antarctic Pack-Ice Seal (APIS) project, conducted aerial and shipboard surveys around the continent during 1996â2001, and also included deployment of satellite-linked dive recorders to investigate haulout behaviour. APIS surveys resulted in an estimate of 35,500 (95% CL 10,900â102,600) Leopard Seals in the surveyed areas (Southwell et al. 2012). All estimates have considerable uncertainty associated with them, and only very large changes in Leopard Seal population size could be confidently detected from repeated surveys(Southwell et al. 2008).

Threats

There are currently no major threats from human activity within the speciesâ normal range.

Learmonth et al. (2006) list the effects of global climate change on Leopard Seals as unknown. However, loss of sufficient areas of pack ice habitat suitable for pupping, resting and avoidance of predators, and availability of preferred prey such as Penguins, other Seals, Krill and fish that might all possibly decline, could effect Leopard Seals directly or indirectly to an unknown degree. The effects of loss of large amounts of ice on the Antarctic continent, general climate warming, or sea level rises, on Antarctic ocean circulation and productivity and on Antarctic marine resources such as Seals are unknown. Siniff et al. (2008) suggested that similar to Crabeater Seals, Leopard Seals would be less affected by changes in sea ice than Ross or Weddell Seals.

Two species of Antarctic ice seals, Leopard and Crabeater, have tested positive for antibodies to canine distemper virus (CDV). The effects of an outbreak of this or other diseases on Leopard Seals either as a disease within this species, or repeatedly transmitted to it from an outbreak in a prey species such as the Crabeater Seal, are unknown. Leopard Seals are generally solitary except when females attend their pup or when pairs mate, so transmission of disease within the species would likely be slow or only seasonally significant. CDV is believed to have arrived in the Antarctic with sled dogs before the advent of vaccines. A mass mortality of Crabeater Seals occurred in 1955, with many animals displaying viral illness symptoms prior to death, but the exact cause of death is unknown (Bengtson and Boveng 1991).

Seasonal tourism in the Antarctic and Sub-Antarctic has increased steadily in the last 30 plus years, and is currently at all-time high levels. The effects of increased vessel noise, disturbance from vessels passage, and close approaches by people in small boats and on land on Leopard Seal behaviour, distribution and foraging are unknown. There is also a risk of injury to a small number of animals from collision with boats or crushing from large vessels passing through ice fields.

There are no reports of significant fisheries interactions. Commercial harvest of Krill may pose direct or indirect threats to Leopard Seals, if conducted on a large scale.

Uses and trade

Small numbers of Leopard Seals have been taken for research purposes and some were previously killed for dog food, but otherwise there is no current or past significant catch of this species (Reijnders et al. 1993).

Conservation

The Leopard Seal is not listed as endangered or threatened on any national Red List. Under the Antarctic Treaty's Convention for the Conservation of Antarctic Seals, the global quota set for Leopard Seals is 12,000 animals annually, but currently there is no harvesting.

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