Japan Sea-Farming Association Akkeshi Station, Akkeshi, Hokkaido 088-1108, Japan
Japanese sandfish Arctoscopus japonicus were raised from larvae to juveniles in a net-cage, being fed only with light-allured zooplankton. Species of attracted plankton were analyzed together with gut contents and growth performance of sandfish. Fish were raised from 3 to 53 days after hatching with a stocking density of 250 ind./m3 in a 20m3 net cage provided with night-time lighting from above. Thirty-eight items of zooplankton were found, the estimated amount of which ranged from 36×104 to 393×104 ind./night for the cage. Podon leuckarti and Centropages abdominalis were the dominant species followed by Euphausiacea and Hippolytidae. Sandfish larvae started to feed from 3 days after hatching on P. leuckarti. Although the diversity of food items increased as the fish developed, species compositions in their gut basically reflected those in the net cage. Daily growth rate of the fish was 0.5mm/day and the survival rate was 98.9%.