口永良部島の本村湾における磯魚の垂直分布

The study reef lies along the shore line of Honmura bay in Kuchierabu Island and drops off gradually into a sandy bottom 10-20m deep and 150-200m from shore. The reef bottom is strewn with boulder and is dotted with dead coral shelf at the off-shore reef end. In the study reef diurnal wandering fish were observed along three zones partitioned by depth and distance from shore in October 1972 and in February 1973; the shore zone 1-5m deep, the mid-shore zone 5-10m deep, and the off-shore zone 10-20m deep. The fish observed were a total of 4115 specimens of 79 species except for the resident and creeping fishes. The fishes in October and February quite similar in species and specimen composition. But they varied with the depth of water each month. Since a large part of fish shifted vertically toward the shore and mid-shore zones in October and toward the off-shore and mid-shore zones in February, the fish of the off-shore zone in October and of the shore zone in February were different from the others. Most of smaller of immature fishes 5-15cm in total length restricted to the shore and mid-shore zone, but many of the large or adult fish of larger than 15cm in total length ranged over the three zones and comprised more than 90 % to the total specimens of the off-shore fishes.