Effects of feeding period on development, growth, and survival of larvae of the fighting conch Strombus pugilis Linne, 1758 (Mollusca, Gastropoda) inthe laboratory

Fighting conch, Strombus pugilis, larvae were reared from hatching to settl ement under two feeding schedules: larvae were fed during 12 light hours (0 6:00-18:00, Set A) and larvae were fed during 12 dark hours (18:00-06.00, S et B). The study evaluated the effect of food availability during the day o r night on larvae development, growth and survival. Adult heart appeared at 8 d in the larvae fed at night and after 11 d for larvae fed during light hours. The settlement period was significantly shorter in larvae of Set B. The veligers fed at night were competent for settlement in between 27 to 29 d, while the settlement had not been reached 100% for the larvae fed durin g the day. The percentage of survival at settlement was significantly lower for larvae fed during the day (29%), while larvae fed at night presented 3 7%. Average larval growth was 23.26 mum d(-1) for day feeding and 41.43 mum d(-1) for night feeding. The siphonal length at settlement for larvae fed at night was 1496 mum. Results obtained indicate that the larvae are more e fficient if cultivated when they are fed at night.