Ecology of plaice (Pleuronectes platessa) in fish assemblages of beaches of the Opale coast (North of France) during spring 1997

Harlay X., Koubbi P., Grioche A.

Date de parution: février 2001
Volume: 25
Number: 1
Pagination: 067-080
Editeur: Société Française d’Ichtyologie
doi: https://doi.org/10.26028/cybium/2001-251-006
Résumé

In recent years, many studies on the ecology of demersal populations nurseries have focussed on subtidal areas and estuaries, whereas the intertidal zone, especially sandy beaches, have been more or less neglected. Weekly sampling was carried out over 7 weeks in spring 1997, at three intertidal beaches (Merlimont, Wissant and Oye-plage) along the Opale Coast. The aim was to determine whether the intertidal zone is of any ecological importance for flatfish. Sampling was achieved with a standard beam trawl, as the one used by local fishermen. Each sampled site showed low diversity of the ichthyofauna and was dominated by the plaice, Pleuronectes platessa and the shrimp, Crangon crangon. Analysis of plaice abundance and size distribution showed differences among beaches throughout time. To the south, succession of cohorts was observed whereas a weekly settlement is suggested for the northern beaches. The variability of plaice settlement dynamics in those areas might be influenced by temperature and tides as well as by mutual predation between young plaice and shrimp, which influence the plaice dynamics. This study shows the role of sandy beaches as an ecosystem temporally occupied by young flatfish throughout this period of their life cycle.

Mots-clés: France - Juveniles - Nursery - Opale Coast - Pleuronectes platessa - Pleuronectidae - Sandy intertidal beaches
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