A Multispecies Virtual Population Analysis for the Southern Chilean Demersal Fishery

Abstract

A multispecies virtual population analysis (MSVPA) model for the southern Chilean demersal fishery was developed. Species included the Southern Hake Merluccius australis, Pink Cusk‐eel Genypterus blacodes (hereafter, “Kingklip”), Southern Blue Whiting (SBW) Micromesistius australis, and Patagonian Grenadier (also known as Argentine Straptail) Macruronus magellanicus (hereafter, “Hoki”). Due to a lack of stomach content data, we constructed suitability coefficients based on predator–prey size ratios. Terminal fishing mortality (Fterm) was estimated by fitting a cohort analysis model to estimates of abundance from single‐species models developed by the Chilean Instituto de Fomento Pesquero (IFOP; Institute for Fishing Development). Values of Fterm were used as input data in the MSVPA, driving the dynamics of the species and producing adult abundance estimates that were similar to IFOP estimates. Comparison of MSVPA and IFOP estimates suggested consistency in adult abundance and total abundance estimates for SBW. Differences were identified for adult Hoki abundance estimates. Differences in recruitment estimates were small for SBW, whereas greater differences were found for Hoki. The MSVPA revealed high estimates of predation mortality for Hoki, while predation played a minor role in SBW population dynamics. Cannibalism and predation by Southern Hake were the main components of predation mortality for age‐0 Hoki; Southern Hake were the most important source of predation for age‐1 Hoki. Sensitivity analysis suggested that Hoki response variables were sensitive to 10% perturbations in suitability coefficients, while SBW response variables were not. This study is a first step toward building a multispecies framework that could provide complementary information for the sustainable management of fishing resources in southern Chile. Received October 11, 2015; accepted March 5, 2016

A multivariate statistical analysis to determine catch intention in the pink cusk-eel (<em>Genypterus blacodes</em>) longline fishery in southern Chile

“…In addition, the artisanal fisheries that target this species only operate inside the fjords and inner channels of the austral zone, where industrial operations are banned. Catch composition of the Chilean demersal southern fishery (CDF) is based on several species, which are caught simultaneously in the same area (Jurado-Molina et al 2016). However, there are only three or four species which account for large part of the catch percentage and its economic value.…”