キジハタ仔魚の摂餌日周期性の検討ならびに日間摂餌量の推定

Abstract

This paper describes the diurnal rhythm of feeding activity and daily ration estimated by a new approach for reared larval red spotted grouper Epinephelus akaara. The larva fed only during the daytime, and the number of food organisms in the gut increased at dawn and dusk, however, the number remained at a moderate level during the middle of the day. This phenomenon became more evident as larval growth proceeded. The larvae of TL 3.9 and 9.9 mm fed on 193 rotifers and 293 Artemia nauplii per day, respectively. The daily food uptake was estimated to be 30.1% of the wet body weight in the 3.9 mm larva and 28.2% in the 9.9 mm larva. The growth rate of this species was relatively higher compared with those estimated in marine fish species, although the food uptake was relatively low.