Variations in the distributions of Centropages chierchiae and Temora stylifera (Copepoda: Calanoida) in the north-eastern Atlantic Ocean and western European shelf waters

Centropages chierchiae and Temora stylifira occurred rarely in the Continuous Plankton Recorder (CPR) survey in the Bay of Biscay, Celtic Sea, and English Channel before 1988. By 2000 they were found frequently and in abundance. The seasonal cycles of abundance of these species differ, C. chierchiae occurring mainly in the summer while T stylifera was found most frequently in late autumn or winter towards the northern limits of its distribution. The increase in abundance of both species is related to temperature. However, in the years when it was found in the samples, the frequency of occurrence of C chierchiae was correlated positively with the strength of the shelf edge current and negatively with the North Atlantic Oscillation (NAO) while the reverse was true for T. stylifera. (c) 2005 International Council for the Exploration of the Sea. Published by Elsevier Ltd. All rights reserved.