Demersal fish assemblages of Faroe Bank: species composition, distribution, biomass spectrum and diversity

Abstract

Sixty-one fish species were caught in 303 trawl hauls in annual spring bottom surveys between 1983 and 1996. Based on cluster analyses, the Faroe Bank fish fauna can be grouped into 3 assemblages: shallow, intermediate and deep assemblage. The boundaries of these assemblages are strongly connected to depth, whereas the relatively homogeneous oceanographic features have a relatively small influence. Although the total number of species is high, the 4 most common species make up more than 60%, both of the total abundance and biomass. A change in species composition has occurred on the Faroe Bank during the last decades. The fish assemblage on the Faroe Bank is mainly boreal, but the occurrence of Arctic as well as Mediterranean species bears witness to the composite nature of the area. Distribution maps of the most common species are presented. The fish species are distributed regularly across the depth range from 95 to 771 m. Preferred depth for the most common fish species are also given. The highest species diversity was found on the southwestern (1.295) and western sides of the Bank (1.261). Species diversity increased with depth and was highest at depths of >500 m. The highest evenness index (0.611) was found in the shallowest area.