口永良部島の本村湾における磯漁の種類組成

The species composition of the reef fishes at Honmura Bay of Kuchierabu Island was observed by underwater visual census2) in February, April, August, and October of 1972. Over 7800 individuals of 81 species were observed. The abundant fish of this reef were species of Scaridae, Acanthuridae, Labridae, Mullidae, Girellidae Lethrinidae, Kyphosidae, Siganidae, and Chaetodontidae. The wandering fish fauna consist of 48 – 65 species. According to the value of λ6) and CII7-8) the species composition of four study months had high diversity and were similar to each other.

The fish observed can be divided into two groups except for four unidentified species (marked by• in Table 1);
(1) tropical fishes; they count 71 species in all,
(2) subtropical fishes; they count 6 species.

In each study month the tropical fishes take up 82.5 - 94.5 per cent of the whole number of individuals observed, and the subtropical fishes only reached 5.5 - 17.5 per cent.

These results suggest that the wandering fish fauna of Honmura reef has a predominantly tropical character.