SPAWNING OF PLAICE PLEURONECTES-PLATESSA L AROUND THE ISLE-OF-MAN, IRISH-SEA

The locations and timing of plaice Pleuronectes platessa spawning arou nd the Isle of Man were studied from distributions of recently spawned eggs recorded in plankton samples. The area of intense spawning activ ity south-east of the Isle of Man was found to be further north than i ndicated in the literature. A previously disregarded spawning ground o ff the west coast of the Isle of Man was identified in 1991, 1992 and 1993, although egg densities were lower than off the east coast. Produ ction of stage I eggs on the west coast spawning site was estimated at approximately 2% of the total plaice egg production in the Irish Sea. This would be sufficient to supply the local nursery grounds on the w est coast of the Isle of Man with plaice larvae. Plaice spawned betwee n early February and early April off the west coast of the Isle of Man , with March as the main period of egg production. Plaice therefore sp awn well before the spring plankton bloom in the Irish Sea. (C) 1997 I nternational Council for the Exploration of the Sea.