Distribution and Population
Crabeater seals have a continuous circumpolar distribution surrounding Antarctica, with only occasional sightings or strandings in the extreme southern coasts of South America, Africa, Australia and New Zealand. They spend the entire year on the pack ice zone as it advances and retreats seasonally, primarily staying within the continental shelf area in waters less than 600 m deep. They colonized Antarctica during the late Miocene or early Pliocene (15-25 million years ago), at a time when the region was much warmer than today. The population is connected and fairly well mixed (panmictic), and genetic evidence does not suggest any subspecies separations.
Currently, no reliable estimates of the total crabeater seal population are available. Past estimates relied on minimal opportunistic sighting and much speculation, ranging from 2 million to 50-75 million individuals. The most recent point estimate is 7 million individuals, but this, too, is considered a likely underestimate. An international effort, the Antarctic Pack Ice Seal initiative, is currently underway to evaluate systematically collected survey data and obtain reliable estimates of all Antarctic seal abundances.
Fossil leopard seals are known from the Pleistocene of South Africa.
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