Species Composition and Seasonal Changes of Copepod Fauna in the Vicinity of Mukaishima

Abstract

Twenty-one species of copepods are identified from the vicinity of Mukaishima in Bingo-Nada. Among them, Eucalanus mucronatus, E. subcrassus, E. crassus, Acrocalanus gracilis, Pseudodiaptomus marinus and Microsetella norvegica are newly found in this area. The first three species occurred only in autumn. Acrocalanus gracilis occurred from autumn to early winter. The other two species were found throughout the year. Dominant species in copepod communities were Paracalanus parvus, Acartia clausi, Oithona similis, O. nana, Oncaea venusta, Corycaeus affinis and Microsetella norvegica. They thrived throughout the year except for Acartia clausi which does not exist from August to November. Of the other species, Calanus helgolandicus, Centropages abdominalis, Euterpina acutifrons mainly appeared in the colder season, and Centropages yamadai, Calanopia thompsoni, Labidocera bipinnata, Pontellopsis tenuicauda, Acartia erythraea and Tortanus forcipatus mainly in the warmer season.