Effect of fishing tactics on the standardization of cardinalfish (Epigonus crassicaudus) catch rates in the demersal multispecies fishery off central Chile

Abstract

We analyzed the allocation of effective fishing effort and the standardization of cardinalfish (Epigonus crassicaudus) catch rates in the multispecies demersal trawl fishery off central Chile. The period analyzed covered from 1997 to 2004 and included detailed information about fishing hauls. Each haul that contained cardinalfish was assigned into a particular fishing tactic (cluster) by using multivariate analysis of their catch composition. The catch rate standardization was carried out by generalized linear models (GLM). Three fishing tactics were discovered: the first directed effort at cardinalfish, the second at common hake (Merluccius gayi gayi), and the third at Patagonian grenadier (Macruronus magellanicus). Fishing tactic was used as an explanatory variable in the proposed GLM. The fishing tactic effect was one of the most important factors in explaining the variance in the GLM. These results are discussed in the context of how the assignation of a fishing tactic allows unbiased abundance indices to be obtained in this kind of multispecies demersal fishery.