Latin american journal of aquatic research
On-line version ISSN 0718-560X
PARRAGA, Diana et al. Characterization of fishing tactics in the demersal crustacean multispecies fishery off Chile. Lat. Am. J. Aquat. Res. [online]. 2012, vol.40, n.1, pp. 30-41. ISSN 0718-560X.
In multispecies fisheries, each fishing operation can be described by analyzing the catch composition, fishing location, and fishing gear used. Sets of fishing operations with similar characteristics have been usually defined as fishing tactics. The present work defines fishing tactics for the crustacean multispecies fishery (CMF) developed between 26°03'S and 38°28'S off Chile. The catch composition per fishing haul, as recorded by scientific observers in fishing a logbooks from 2007 to 2009, was used. During this period, 1599 fishing hauls containing 57 species were registered in total. After employing a principal component analysis to reduce the species composition dimension, an agglomerative hierarchical analysis was carried out over the retained components. Four fishing tactics were identified and analyzed: 1) effort directed to Heterocarpus reedi (red shrimp) over a wide latitudinal range, 2) effort focused on Cervimunida johni (yellow squat lobster) in a narrow latitude range and at shallower depths, 3) effort directed to Haliporoides diomedeae (red royal shrimp), with the deepest hauls, and 4) effort focused on Pleuroncodes monodon (red squat lobster) in shallower waters close to the coast. In the case of the CMF, the identification of fishing tactics is important for indicating catch intention and for constructing abundance indices using data derived from fishing a logbooks. The results are discussed in terms of characterizing the fishing tactics and how their designation allows obtaining less biased abundance indices.
Keywords : demersal crustaceans; species composition; multivariate analysis; Chile.