Spatial and temporal patterns in the bycatch of seabirds in the Argentinian longline fishery

Longline fisheries have grown throughout the world’s oceans for more than 40 years. This type of fisheries has captured high-quality fish (mature individuals rather than unwanted juveniles), has had minimal destructive effects on bottom habitats, and has produced a low bycatch of nontargeted fish (Brothers et al., 1999). Seabirds, however, are hooked accidentally when they swallow or are snagged on the baited hooks set by commercial longline crews (Brothers, 1991; Barnes et al., 1997; Tasker et al., 2000; Belda and Sanchez 2001; Jahncke et al., 2001). Population declines of several species of albatrosses and petrels in the Southern Ocean are linked to longlining operations (Croxall and Prince, 1990; Brothers, 1991; Cherel et al., 1996). The importance of the Patagonian shelf waters as a foraging habitat for seabirds is well documented (Cooke and Mills, 1972; Veit, 1995), particularly for black-browed albatross (Thalassarche melanophris; Gales, 1998). We estimated the magnitude of seabird mortality in the kingclip (Genypterus blacodes) fishery in the Argentine Exclusion Economic Zone (EEZ).