INTERACTIONS BETWEEN LONGLINE VESSELS AND SEABIRDS IN KERGUELEN WATERS AND A METHOD TO REDUCE SEABIRD MORTALITY

A longline fishery for Dissostichus eleginoides has recently developed in the vicinity of South Georgia and Kerguelen islands, two internati onally important breeding areas for procellariiform birds. The number of hooked birds and a method to reduce mortality were investigated dur ing 13 days of fishing activity in Kerguelen waters in February 1994. Between 100 and 600 seabirds were always observed behind the longline vessel during daytime. The main ship-following species were the white- chinned petrel Procellaria aequinoctialis (67% of counts), giant petre ls Macronectes spp. (8%) and the wandering albatross Diomedea exulans (11%), black-browed albatross D. melanophris (6%) and grey-headed alba tross D. chrysostoma (2%). Only diving species were caught on the line s, ie. the white-chinned petrel (n = 36) and the grey-headed albatross (n = 2). Marked differences in the mortality rate were observed betwe en day and night (1.00 versus 0.38 birds per 1000 hooks), and at night when the decklights were on or off (0.59 versus 0.15 birds per 1000 h ooks). Dumping of homogenized offal during line settings greatly reduc ed incidental capture of seabirds, mainly because birds were more attr acted by offal than by hooked baits. We therefore propose that the dum ping of offal during line settings should be included in the regulatio ns of the longline fishery for Dissostichus in order to minimize seabi rd mortality.