水槽内における海水魚の種内・種間関係 : I チョウチョウウオ類

抄録

Intra-and interspecific chasings of immature butterfly fishes were studied in an exhibition tank (110cm×170cm×80cm) of the Suma Aquarium. Observations were made on 35 fishes belonging to 13 species in October 1961. For seven species, Chaetodon collaris, C. auriga, C. lunula, C. lineolatus, C. vagabundus, C. melanotus and Heniochus acuminatus, among which nine species had more than two individuals each in the tank, intraspecific chasing was far more frequent and eminent than the interspecific one. On the contrary, though only few data were available, the other two species, Chaetodon nippon and C. ephippium, appeared to chase fishes of other species as well as those of their own species. For the remaining species, it is at present difficult to conclude with certainty. Interspecific chasing of Heniochus acuminatus is concentrated mainly to H. singularius, and the latter chased the former back, but hindered no other species. This may suggest that fish is likely to chase a fish of another species of shape and colour resembling its own. The frequency of intraspecific chasing in any species was much higher before and during feeding than after, while the frequency of interspecific chasing decreased apparently before and during feeding.