Abstract
KANAMOTO, Ziyusei (Dep. Fish. Biol., Fac. Agr., Tohoku Univ., Sendai). 1900. On the ecology of hexagrammid fish. III. Niches of Agrammus agrammus (TEMMINCK et SCHLEGEL) and Hexagrammos otakii JORDAN et STARKS and the mode of life of some reef fish. Jap. J. Ecol., 27 : 215-226. The ecology of many species of reef fish has been studied by means of year-round underwater observation around the reef near Benten Island in Sendai Bay, where twenty-one species of reef fish, including two hexagrammid species, coexist. These fish were divided into three major types according to their mode of life (habitat, feeding habits, method of escape and so on), namaly, touching-type, floating-type and swimming-type. The touching-type fish (Agrammus agrammus, Hexagrammos otakii and so on) spend long periods in a solitary state on the rocks or on the algae growing on the rocks. The floating-type fish (Sebastes inermis and others) remain above the rocks or among the algae growing on the rocks, some in a solitary state, and some in a gregarious state in daylight. The swimming-type fish (Ditrema temmincki, Girella punctata etc.) swim on the surface or in the subsurface and bottom layers, mostly in a gregarious state in daylight. Although many species were observed in this particular area, there were few species which compoted with each other.
