Grenadiers of the World Oceans: Biology, Stock Assessment, and Fisheries

Abstract

<em>Abstract.</em>—The principal aim of this study is to describe the distribution patterns of abundance and biomass, on a seasonal and bathymetric basis of the main macrourid species from the Spanish Gulf of Cadiz. The results from 23 bottom-trawl surveys carried out in the study area in spring and autumn of 1993–2006 were analyzed. The most abundant species captured were common Atlantic grenadier <em>Nezumia aequalis </em>and saddled grenadier <em>Coelorinchus coelorhincus. </em>In terms of biomass, softhead grenadier <em>Malacocephalus laevis </em>was the third most important species and bluntsnout grenadier <em>Nezumia sclerorhynchus </em>and glasshead grenadier <em>Hymenocephalus italicus </em>were the least abundant species. Of the five species caught in the surveys, only <em>N. aequalis</em>, <em>M. laevis </em>and <em>C. coelorhincus </em>were analyzed in detail; their yields expressed in number of individuals/h represented the higher values and showed higher yields in spring than in autumn, suggesting a seasonal pattern of abundance. However, <em>C. coelorhincus </em>did not show this pattern except between 1999 and 2004. <em>N. aequalis </em>showed the widest bathymetric range. The observed yields in the depth gradient for the three species revealed species-specific preferences for a determinate depth range. In relation to mean total size, larger individuals of <em>M. laevis </em>and <em>N. aequalis </em>were observed during the March surveys. <em>C. coelorhincus </em>was the only species that showed a slight increase in mean size with increasing depth.