POPULATION DIVERSITY IN BAY-OF-BISCAY ANCHOVY (ENGRAULIS-ENCRASICOLUS L 1758) AS REVEALED BY MULTIVARIATE-ANALYSIS OF MORPHOMETRIC AND MERISTIC CHARACTERS

The population structure of the anchovy stock exploited in the Bay of Biscay (ICES Division Vlllb and c) and the north-west Iberian peninsula (northern Division IXa) is analysed using 30 morphometric and eight meristic characters. Discriminant function analysis applied to morphometric (shape) characters from commercial catch samples showed that anchovies found in the northern IXa Division are delectably different from those found in the South-east Bay of Biscay (Division Vlllb, east to 4°W). Individuals sampled west to4°W are morphologically more similar to those of Division IXa. All Bay of Biscay anchovies a re clearly separable from those of Mediterranean origin, which were included in (he analysis to lest the suitability of the method as a discriminant tool. Meristic characters do not allow efficient discrimination between individuals from those areas. The aim of this study is only to determine recognizable phenotypic patterns, matching the diversity of environmental conditions existing in the Bay of Biscay, which can contribute to an understanding of the important long-term variability of the slock, both in biomass and geographic distribution. The underlying genetic basis, taxonomic status, or degree olTeproductive isolation of the groups identified are not addressed. © 1993 Conseil International pour l’Exploration de la Mer.