Abstract
Development of bones in the mouth parts and changes of gut contents were investigated in early red snapper Lutjanus argentimaculatus larvae reared with naturally-occurring zooplankton as food. Larvae immediately after initial mouth opening possessed incomplete bony components in the mouth parts. However, the bony elements grew rapidly in size on the day of initial mouth opening, day 0, during which they started feeding. Acartia sinjiensis nauplii of 0.10-0.15mm in total length (TL) were major food organisms at this stage. From day 1 to 2, no conspicuous changes occurred in the size and type of food organisms ingested, although some skeletal elements were added in the mouth part. Many new skeletal elements developed from day 3 to 4, as the size of food organisms in gut increased abruptly. The larvae started feeding on Oithona dissimilis copepodids (0.20-0.50mm TL) and the weight percentages of the copepodids ingested increased thereafter. Early red snapper larvae acquired initial feeding ability by growing the size of a limited number of bony elements in the mouth parts. Further increase in feeding ability was achieved by differentiation of additional bony elements from day 3 to 4.
