Distribution pattern of larval fish populations in the Northwestern Mediterranean

Abstract

Spatiotemporal distribution patterns in the larval fish community were studied off the Catalan coast (NW Mediterranean) between April and October 1983. Important seasonal variations in species composition were detected. The causes of this temporal heterogeneity lay in the species richness of the area and the spawning periods of adults. Spatial heterogeneity depended on the combined effects of topography and hydrographic features of the reglon. The existence of a shelf-slope front along the shelf break was one of the most important factors and was associated with maximum larval abundance. The current running along the coast from north to south together with the diversity of bottom structure and type also made major contributions to spatial heterogeneity. Four distinct geographical zones coinciding with bottom features were differentiated by statistical analysis. The species groups defining these 4 zones largely coincided with habitat and behaviour of the adults. However, with the diversity of features of the regon, the species were not limited solely to a single assemblage, giving rise to a gradation rather than to well-defined associations.