Population densities of pack ice seals in the Lazarev Sea, Antarctica

Abstract

From 15 December 1992–4 January 1993 aerial surveys of ice seals were undertaken by Puma helicopter across the pack ice off Dronning Maud Land. The 31 transects of 1/2 nautical mile (n.m.) width were flown at an elevation of 200 ft and a ground speed of 60 knots and covered 805.6 n.m.2 of pack ice. The overall species composition of the seals was 97.8% crabeater seals, 1.67% Ross seals, 0.34% leopard seals and 0.15% Weddell seals. The density abundance of seals was 2.47 n.m.−2 for crabeater, 0.01 n.m.−2 for leopard, 0.004 n.m.−2 for Weddell and 0.04 n.m.−2 for Ross seals. Leopard seals were largely found near the outer edge of the pack, Ross seals were absent only in the outer pack, whilst Weddell seals were virtually absent in the pack ice. Present throughout, crabeater seals and Ross seals showed a statistically significant preference for the inner pack, the reasons for this being unclear.