ONTOGENIC MIGRATION OF PLEURONECTES FLESUS LARVAE IN THE EASTERN ENGLISH-CHANNEL

Along the French coast of the eastern English Channel there is a stron g separation in the hydrology, zooplankton community and ichthyoplankt on assemblages, between a coastal ecosystem of continental influence a nd an offshore ecosystem of Atlantic influence. During April and May 1 995, two surveys (60 stations) were conducted to describe the early li fe history of fishes in this area, and especially the influence of hyd rodynamics on Pleuronectes flesus larval transfer from the spawning gr ounds to the nurseries. Ontogenic changes in larval distributions were described by variograms and path analysis. P. flesus eggs and young l arvae were found in the southern offshore area. Their distributions we re mainly influenced by sediment and cold temperature found in the cen tral part of the Channel. Older larvae were found al more northern sta tions, showing a clumped distribution near estuaries, in areas of low salinity. Apparently, young stages of this species were transported fr om the south central spawning area to coastal waters by residual curre nts. Behavioural changes in older larvae facilitate the move to nurser ies along the French coast. (C) 1997 The Fisheries Society of the Brit ish Isles.