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Effects of feeding conditions and size differences on aggressive behaviour and cannibalism in the P acific bluefin tuna T hunnus orientalis ( T emminck and S chlegel) larvae
Author(s) -
Ishibashi Yasunori,
Miki Takahisa,
Sawada Yoshifumi,
Kurata Michio
Publication year - 2013
Publication title -
aquaculture research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.646
H-Index - 89
eISSN - 1365-2109
pISSN - 1355-557X
DOI - 10.1111/j.1365-2109.2012.03203.x
Subject(s) - cannibalism , biology , thunnus , tuna , larva , economic shortage , fishery , scombridae , fish <actinopterygii> , zoology , predatory fish , ecology , linguistics , philosophy , government (linguistics)
We examined the effects of feeding conditions and size differences on the aggressive behaviour and cannibalism in Pacific bluefin tuna ( PBT ) T hunnus orientalis larvae. In a 24 h experiment, restricted feeding alone was found to remarkably increase the frequency of aggressive behaviour, which was further elevated by differences in fish size. In a 4‐day rearing experiment, while aggressive behaviour was increased by restricted feeding alone, the frequency of cannibalism did not change significantly. Although the frequency of aggressive behaviour did not increase with difference in size factor, small fish in this group gradually tended to die over 4‐day period. In the restricted feeding and size difference group, large fish were observed to bite the small fish, and almost all the small fish died on the day after the start of the experiment. These results suggest that the aggressive behaviour of PBT larvae is chiefly increased by the shortage of live food; however, deaths related to cannibalism mainly occurred in small larvae and rapidly increased with food restriction and differences in fish size.