Trends in entanglement of Antarctic fur seals ( Arctocephalus gazella) in man-made debris at South Georgia

Abstract

A study conducted at South Georgia in 1988/1989 indicated that several thousand Antarctic fur seals were entangled mainly in man-made material originating from fishing vessels. Consequently, the authority responsible for the management of Southern Ocean marine resources (CCAMLR) actively campaigned for compliance with the MARPOL provisions relating to waste disposal at sea, and for cutting of any material unavoidably jettisoned which could form collars to entangle seals. Five subsequent years of recording entangled fur seals confirms that entanglement is a persistent problem, although its incidence has been halved in recent years. However, the South Georgia fur seal population has approximately doubled in the same period, so that the overall total of animals entangled may even have increased. Nevertheless, because most seals entangled are juvenile males, the current rate of entanglement will have negligible effects on the reproductive rate of the South Georgia population, especially in relation to its current rate of population increase. The reduction in observed entanglement incidence cannot be attributed mainly to improved waste disposal practices because it has coincided with substantial reductions in fishing activity around South Georgia. However, the particular reduction in entanglement due to packing bands and the fact that all such bands washed ashore over the last 2 years have been cut, does suggest a general improvement in standards of waste disposal on Southern Ocean fishing vessels.