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 VIIIb 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 detectably different from those found in the South-east Bay of Biscay (Division VIIIb, east to 4°W). Individuals sampled west to 4°W are morphologically more similar to those of Division IXa. All Bay of Biscay anchovies are clearly separable from those of Mediterranean origin, which were included in the analysis to test 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 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 stock, both in biomass and geographic distribution. The underlying genetic basis, taxonomic status, or degree of reproductive isolation of the groups identified are not addressed.