Diet of larval sardine, Sardinops melanostictus in Toyama bay, southern Japan sea [Japan]
1996
Hirakawa, K. (Japan Sea National Fisheries Research Inst., Niigata (Japan)) | Goto, T.
The types and size of food particles eaten by larvae of the Japanese sardine, Sardinops melanostictus, were determined by gut content analysis of larvae (SL: 4.3-8.0 mm) captured during daylight hours from Toyama Bay in May 1994. Copepod eggs and nauplii were numerically the most important food items. Food composition changed as the larvae grew; the proportion of eggs decreased with increasing size of larvae, while correspondingly the proportion of nauplii increased. The nauplii eaten consisted of various species. As a whole, cyclopoid (Oithona spp.) nauplii were the most important dietary component, with calanoid (mainly Paracalanus type) nauplii second. Such food composition is in part a reflection of the abundance and species composition of copepods in the field. Maximum prey size (length and width) increased with size (SL) of larvae, whereas minimum prey size increased less; the size of prey consumed showed a large range in sizes, from 0.07 to 0.45 mm in length and 0.05 to 0.20 mm in width. Within these size constraints, rare copepod species such as Calanus sinicus and Oithona plumifera seem to make a major contribution to larval growth (SL: 5.1 to 8.0 mm) because of their large body size, although the more abundant and smaller size copepods (possible Oithona similis) are more commonly eaten
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