Fish larvae samplings were made in the western Wakasa Bay, the Japan Sea during May and June, 1981. In view of the vertical distribution and feeding, differences among three species of Scorpaenidae larvae,
Sebasticus marmoratus (CUVIER),
Sebastes oblongus GÜNTHER and
Sebastes pachycephalus pachycephalus TEMMINCK et SCHLEGEL are to be expected.
The larvae of three species distributed abundantly in the shallow waters, especially in the water between 0m and 25m depths.
Plankton species belonging to Crustaceae was utilized as main food for all three species, of which
S. marmoratus and
S. pachycephalus pachycephalus began to feed on copepod nauplii and invertebrate eggs at yoek-sac stage. Copepod nauplii was indispensable food for three species larvae of less than 6.0mm BL. The main food of
S. pachycephalus pachycephalus of more than 7.0mm BL were
Evadne nordmanni, Acartia clausi, Paracalanus parvus, Oithona spp. and
Calanus helgolandicus, and the food composition in the gut was very similar to plankton composition observed in the sea. Main food items were
P. parvus, E. nordmanni and copepodites in
S. marmoratus larvae of more than 6.0mm BL, and
E. nordmanni, copepodites and copepod nauplii in
S. oblongus larvae of more than 6.0mm BL.
The relationships between larvae size of three species and their food size, suggests that the larvae of
S. marmorautus and
S. pachycephalus pachycephalus discriminate prey size as growth proceeded.
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