The population dynamics of O-group flatfish on nursery grounds in the Clyde Sea Area

The plaice, Pleuronectes platessa L., is the most commercially important flat-fish in the Clyde Sea Area. For midsummer (1 August), population estimates of 10–20 million O-group fish were derived. These fish were mainly distributed on fine sand in bays at depths of less than 3 m. Over 95% occurred in bays along the Ayrshire coast; Irvine and Ayr Bays were the most important nursery grounds. The mortality rate appeared to be of the order of 50% per month during the late summer and autumn but this was probably a considerable overestimate. Comparable data for the common dab ( Limanda limanda L.) are provided. The benthic communities of the intertidal and shallow sublittoral zones which provided food for the flatfish were examined. The Ayrshire bays carried an extremely well developed Tellina tenuis da Costa community with abundant individuals, varied species diversity and high biomass. Irvine Bay was the most productive area.