Relationships between feeding habits of fish larvae and their food organisms in the western Wakasa Bay

Abstract

Examinations were made of the relationships between feeding habits of 12 fish larvae and their food organisms collected in the western Wakasa Bay of the Japan Sea form May ot August 1981.
Copepod nauplii was availabile food for all of the small size larvae of less than 4.0mm BL, and for large size larvae of three species which distributed abundantly in the surface waters. Four plankton species, Oikopleura longicauda, Paracalanus parvas, Evadne nordmanni and Penilia avirostris were consumed as main food by the larvae of more than 6.0mm BL, and feeding percentage of this size larvae was high. The larvae fed on the former two food organisms regardless of the food density in the survey area, however, the latter two food organisms were consumed only when they distributed densely.
Through a series of study on feeding habits of 12 fish species at the larval stage, it was found that the amount of food organisms available to the larvae of more than 6.0mm BL was sufficient in the area, though the food organisms were utilized under competition.