THE FOOD AND THE FEEDING-HABITS OF THE LONG ROUGH DAB, HIPPOGLOSSOIDES-PLATESSOIDES (FABRICIUS 1780) IN THE NORTH-SEA

The type and quantity of food, the feeding intensity as well as the diel feeding pattern of the long rough dab Hippoglossoides platessoides are described. The interaction of the species with the biological environment is also assessed. The North Sea long rough dab feeds throughout the year with a definite maximum from April till August when over 85% of the fish sampled were feeding. It feeds principally on crustaceans (natant decapods), polychaetes, and echinoderms (ophiuroids), but also consumes O-group whiting (Merlangius merlangus), long rough dab, and gobies (Gobiidae) in the east-central North Sea nursery grounds during the summer months. The species does not compete strongly for food with the other three most abundant pleuronectids, viz. plaice (Pleuronectes platessa), common dab (Limanda limanda) and lemon sole (Microstomus kitt), as shown by a comparison of major prey items in their stomachs and the anatomical structure of their digestive tracts. The differences in the diet between the North Sea population(s) of long rough dab and the population(s) of the species from other North Atlantic areas are probably a manifestation of ecological differences amongst these ecosystems, especially in the availability and the distribution of prey organisms.