The impact of climate change on the fish community structure of the eastern continental shelf of the Bay of Biscay

Abstract

Abstract Many fish species are at the southern or northern limit of their distribution range in the Bay of Biscay, where large-scale hydroclimatic changes have occurred in recent decades. We attempt here to identify the impact of these changes on the fish community of the eastern continental shelf of the Bay of Biscay. Data collected during 14 autumn groundfish surveys in 1973 and from 1987 to 2002 are used. The study area is between latitudes 48°30′N and 43°30′N while the depth ranges from 15 to 200 m. Annual abundance indices (number of individuals per km2) of 56 fish taxa present on average in at least 5% of the tows are computed. Multivariate analysis is used to detect temporal trends in these species' abundance indices. Assuming that increased water temperature may favour subtropical species and hinder temperate ones, knowledge about the latitudinal distribution range is used to interpret time trends. Results show an increasing abundance trend with time for fish species having a wide distribution range in latitude (mainly subtropical ones), whereas the abundance of temperate and the least widely distributed species decreased steadily.