Feeding activity of marbled sole Pleuronectes yokohamae larvae and juveniles reared in the dark in a laboratory
2005
Yamamoto, S.(Okayama-ken. Fisheries Experiment Station, Setouchi (Japan)) | Sugino, H. | Cyuriki, K. | Masunari, N.
The ontogenetic onset and feeding activity in the dark were investigated for marbled sole Pleuronectes yokohamae reared in a laboratory during 5 to 60 days old after hatching. The numbers of food organisms (rotifers Brachionus sp, and nauplii of Artemia sp.) in the gut were counted as the index of feeding activity. Larvae 25 days old could not feed in the dark. However, ingestion of food organisms was first observed in larvae that were 31 days old and over 8.0 mm in total length (TL). The filling rate in the dark increased with the growth of larvae 9.0 mm TL, but mean number of food organisms ingested in the dark was fewer than that in the light. Therefore, it appeared that their feeding activity in the dark was inferior to that in the light These results indicate that the larvae and juveniles larger than 8.0 mm TL of P, yokohamae feed mainly during the daytime, and feeding activity in the dark at night is not always enough for capturing of food organisms.
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