Hook selectivity in the longline fishery of Dissostichus eleginoides (Nototheniidae) off the Chilean coast
Existing information from technical publications on Chilean fisheries of the Patagonian toothfish, Dissostichus eleginoides is reviewed in order to study selectivity of different types and sizes of hooks used in longlines. Original data obtained during 1991 off the coast of Valdivia, South East Pacific, are also taken into consideration. The data show that circle hooks are far more efficient than straight hooks. The length frequency distributions of fish caught with straight hooks Nos 3 and 4 are not significantly different, but hooks No. 3 are nearly 31 % more efficient than hooks No. 4. Using different bait does not result in significant differences. It is worth noting that the ratio of females increases significantly in catches, when the size of straight hooks is increased (e.g., from 4 to 3) or when circle hooks are used instead of straight hooks.