Hatching and early feeding of Japanese sand eel Ammodytes personatus in the Ise Bay

Abstract

Characteristics of hatching and transition from endogenous to exogenous nutrition of the Japanese sand eel Ammodytes personatus population in Ise Bay, central Japan, were studied in the laboratory. Duration to the peak hatching after fertilization were needed for 15, 13 and 11 days at 10.3°C, 12.0°C and 13.9°C, respectively. In the peak day, 46.1%, 62.3% and 73.2% of the total larvae hatched at the corresponding temperatures. Hatching predominantly occurred within 4 hours after onset of dark period at 17:00. Newly hatched larvae started feeding within 24 hours after hatching. All larvae completed yolk absorption within 13 days, but oil globle remained in 40% of the 30 days-old larvae. The sand eel larvae had a long mixed period of endogenous and exogenous nutrition. Daily growth rate during the first 30 days after hatching was 0.23 mm at 10.1deg;C.