INGESTION OF FISHING GEAR AND ENTANGLEMENTS OF SEABIRDS: IMPLICATIONS FOR MONITORING AND MANAGEMENT

Fisheries are increasingly adopting ecosystem approaches to better manage impacts on non-target species. Although deliberate dumping of plastics at sea is banned, not all fisheries legislation prohibits discarding of gear (hooks and line) in offal, and compliance is often unknown. Analysis of a 16 year dataset collected at Bird Island indicated that the amount of gear found in association with wandering albatross colonies was an order of magnitude greater than in any other species, reflecting their wider foraging range and larger gape. Unlike other taxa, most gear associated with grey-headed albatross was from squid and not longline fisheries, and mistaken for natural prey rather than the result of direct interaction. Observed rates of foul-hooking (entanglement during line hauling) were much higher in giant petrels and wandering albatross than black-browed albatross, and no grey-headed albatross was affected. The index of wandering albatross gear abundance showed two peaks, the most recent corresponding with a substantial increase in the number of multifilament snoods (gangions), suggesting that the widespread adoption of a new longline system may have been responsible. Although all identified gear was demersal, given the widespread use of similar hooks, little could be assigned to a specific fishery. Stomach content analysis suggested that 1300-2048 items of gear are currently consumed per annum by the wandering albatross population at this archipelago. Many hooks are completely digested by chicks, long-term effects of which are entirely unknown. We suggest a number of management approaches for addressing the problem of gear discarding, and guidelines for monitoring schemes elsewhere