Cephalopod remains in scats of Weddell seals (Leptonychotes weddellii) at Cape Shirreff, South Shetland Islands, Antarctica

摘要

The diet of Weddell seals (Leptonychotes weddellii) varies regionally, and fish and cephalopods are thought to be the most important food source. However, there is limited information on the cephalopod component of the Weddell seal's diet in the South Shetland Islands. We investigated cephalopod remains in the diet of Weddell seals by analysing 21 scats collected on three beaches at Cape Shirreff, Livingston Island, Antarctica, from 1 to 20 February 1999. Although the number of scats is small and collected from only 1 month a long time ago, fish and cephalopods were present in 21 and 16 of the scats, respectively. Only cephalopods of the order Octopoda were represented. Thaumeledone sp. was the most abundant prey species in terms of numbers, followed by Pareledone charcoti and P. turqueti. The latter two species showed the highest frequency of occurrence in scats (10 and 9, respectively). Graneledone macrotyla, Opistoteuthis sp., Argonauta sp., Haliphron sp. and Thaumeledone sp. are new species identified in the diet of Weddell seals in the present study, but all made a negligible contribution to their diet at Cape Shirreff. Our findings agree with previous dietary studies of Weddell seals at other localities in the South Shetland Islands and the Antarctic Peninsula, which showed a relatively greater contribution of octopods to the diet compared with squid in summer.