Diet composition and prey size of larval anchovy, Engraulis japonicus, in Toyama bay, southern Japan sea
1997
Hirakawa, K. (Japan Sea National Fisheries Research Inst., Niigata (Japan)) | Goto, T. | Hirai, M.
The types and size of food particles eaten by larvae of the Japanese anchovy, Engraulis japonicus, were determined by gut content analysis of larvae (SL: 4.1-8.0mm) captured during daylight hours from Toyama Bay in May 1994. Copepod nauplii were numerically the most important food items. 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. Food composition reflects in part the abundance and species composition of copepods in these waters. The size of prey consumed showed a large range in sizes, from 0.07 to 0.36mm in length and 0.05 to 0.13mm in width. Maximum prey size remarkably in creased for larvae from 4.1 to 5.6mm in size (SL), whereas any increase of minimum prey size was indistinct. Within these size restrictions, rare copepod species such as Calanus sinicus and Oithona plumifera seem to make a major contribution to the larval diet because of the larger body size of these prey, although the more abundant and smaller size copepods (possibly Oithona similis) are more commonly eaten. Food availability for anchovy larvae may depend on reproduction of both warm-and cold-water copepod species in relation to hydrographic structure in the southern Japan Sea
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