水産養殖研究開発ジャーナル

概要

Elasmobranch Distribution and Assemblages in the Southern Tyrrhenian Sea (Central Mediterranean)

Bottari T,Busalacchi B,Profeta A,Mancuso M*,Giordano D,Rinelli P

The aim of this study is to identify elasmobranch species present in the SouthernTyrrhenian Sea, to describe
their distribution and abundance, to identify significant spatial or temporal differences between species. 14 bottom trawl surveys were carried out from 1994 to 2007. 16 species of elasmobranchs were recorded. Multidimentional Scaling Ordination (MDS) showed two groups according to the depth gradient: in the first one the stations from upper slope and in the second one the stations from middle slope. Mean biomass indices and frequency of occurrence showed that Galeus melastomus, Etmopterus spinax and Scyliorhinus canicula were the most abundant species. Mean biomass indices for other species were very low. The mean abundance of G. melastomus exhibited a positive temporal trend in biomass and density. The mean abundance of E. spinax exhibited a negative temporal trend in biomass and in density. For other species abundance varied greatly between years, even if there was no evident trend.