LABORATORY STUDIES ON THE FOOD-INTAKE OF 6 SURF-ZONE FISH SPECIES

Food intake of Lithognathus lithognathus, Lithognathus mormyrus, Pomad asys commersonnii, Lichia amia, Myliobatus aquila and Rhinobatos annul atus was determined under controlled laboratory conditions. Daily fluc tuations in energy intake were observed, with a period of high intake being followed by a period of lower intake. Individual fish consumed 0 - 45% of body weight per day, which was within the range recorded for other species. Daily food intake (dry weight or energy) was affected by fish weight and could be described by the model: Food intake = a(li ve body weight)b. Energy intake of the fish was the highest when they were fed twice a day or when food was continuously available. Energy i ntake of individual fish was higher when either Donax serra or Liza ri chardsonii was fed than when Macropetasma africanus was fed. Energy in take of all the species (except that of R. annulatus) was significantl y influenced by temperature and was generally higher at 20-degrees-C t han at 15-degrees-C. The relevance of these findings is discussed.