Seals and sealing in the Antarctic: Commercial sealing in the 1800s and 1900s was extensive on the islands in the northern regions of the Southern Ocean. Fur seals and elephant seals were reduced to low numbers at many breeding sites and exterminated at some. In the past few decades, the abundance of Antarctic fur seals increased substantially in almost all its colonies and nowadays may exceed 5 million. The elephant seals are still recovering from the commercial harvest. Several colonies have remained stable over the last three decades while others began to decline for as yet unexplained causes. Crabeater, Ross, leopard and Weddell seals, typically found in the high-Antarctic sea ice zone, have seldom been hunted. Estimates of crabeater seal abundance vary widely between 11 and 30 million. Although potential biases and considerable uncertainties underlying the earlier estimates have been adequately identified meanwhile, some are still likely to affect even the most recent surveys. During a circumpolar census, conducted in 1983, markedly lower densities of crabea¬ter seals were observed than levels reported in the 1960s and 1970s. It is unknown whether these observations reflect a real decline in the population size of this species. The international »Antarctic Pack Ice Seals« pro¬gram completed in 2000 that surveyed seals on the pack ice around Antarctica was supposed to provide firmer estimates of the species’ abundances and geographical population densities. Although this was successful on a regional scale, the total estimates remains uncertain.