Fish Communities in the Surf Zone of a Protected Sandy Beach at Doigahama, Yamaguchi Prefecture, Japan

Abstract

Fish communities comprising postlarval to early adult stages were studied in the surf zone of a protected sandy beach, with runnels and a low tide terrace, at Doigahama, Yamaguchi Prefecture, western Japan. One elasmobranch and 100 teleost species, represented by a total of 17608 individuals (1·85–785mm in TL), were collected by fine and coarse meshed beach seines from May 1994 to April 1999. Species richness, abundance and biomass were greater during the evenings as well as in the warmer seasons (May to October). Larval and smaller juvenile ichthyofauna (collected mainly by fine-mesh seine) was relatively poor compared to larger juvenile ichthyofauna (coarse-mesh seine). Tidal effect was observed in the fine-mesh seine samples, whereas no tide-related trends were evident in the coarse-mesh seine samples. Effects of time of the day and tide on the species diversities were not so evident in both seines. Dominant species were classified according to the developmental stages occurring in the surf zone, as follows: Type-I: Postlarval (transformation) stage (Plecoglossus altivelis altivelis,Sardinops melanostictus , Enneapterygius etheostomus, Tripterygion bapturum, Luciogobius sp.). Type-II: Juvenile stage (Lateolabrax latus, Trachurus japonicus, Gerres oyena, Acanthopagrus schlegeli, Sparus sarba, Girella punctata, Mugil cephalus cephalus, Paralichthys olivaceus, Tarphops oligolepis, Heteromycteris japonica). Type-III: Postlarval and juvenile stages (Spratelloides gracilis, Engraulis japonicus, Gobiidae sp.1). Type-IV: Juvenile and early adult stages (Sillago japonica, Paraplagusia japonica). Type V: Postlarval to early adult stages (Takifugu niphobles). It is considered that the surf zone at Doigahama functions as a nursery area, particularly as a feeding place for larger juveniles than as a shelter for larvae and smaller juveniles.