Demersal resource assemblages in the trawl fishing grounds off the Balearic Islands (western Mediterranean)

Abstract

The demersal resources distributed in the trawl fishing grounds off the Balearic Islands (western Mediterranean) were studied from two bottom trawl surveys carried out in spring and autumn along the continental shelf and upper slope off the islands of Mallorca and Menorca. A total of 88 hauls, between 41 and 745 m depth, were analysed by means of multivariate analysis and ecological parameter calculation in order to characterise the structure of commercial species assemblages. A different bathymetric distribution of abundance was observed by comparing the main taxonomic groups. Six main species assemblages were identified, primarily associated with depth but also with different macro-epibenthic communities. Seasonal or geographic differences were detected for three of these assemblages, which could be related to differences in habitats and macro-epibenthic communities, as well as to seasonal changes in the abundance of some species related to their life cycle.

Keywords

• demersal resources
• bathymetric distribution
• species assemblages
• macro-epibenthos
• bottom trawl
• balearic islands
• western mediterranean