Reduced cannibalistic behavior of African catfish, clarias gariepinus, larvae under dark and dim conditions
In general, African catfish shows higher survival rates in the dark conditions than in the light conditions. In this study, larval behavior of African catfish was observed under 0, 0.01, 0.1, 1, 10, and 100 lx using a CCD camera to investigate the reason why African catfish larvae show higher sur...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Zoological Society of Japan
2013
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| Subjects: | |
| Online Access: | http://irep.iium.edu.my/30384/ http://irep.iium.edu.my/30384/ http://irep.iium.edu.my/30384/ http://irep.iium.edu.my/30384/1/zoological_science_2013_catfish.pdf |
| Summary: | In general, African catfish shows higher survival rates in the dark conditions than in the light
conditions. In this study, larval behavior of African catfish was observed under 0, 0.01, 0.1, 1, 10,
and 100 lx using a CCD camera to investigate the reason why African catfish larvae show higher
survival rates in dark conditions. The larvae showed significantly higher swimming activity under
0, 0.01, and 0.1 lx than that under 10 and 100 lx. The larvae also showed significantly increased
aggressive behavior under 10 and 100 lx; the swimming larvae attacked resting individuals more
frequently under 10 and 100 lx than under 0, 0.01, and 0.1 lx. The aggressive behavior and sharp
teeth of the attacking larvae appeared to induce skin surface lesions on injured larvae. Chemical
substances were then generated from the injured skin surface, and these chemical stimuli triggered
cannibalistic behavior in other fish near the injured fish. The results of this study demonstrate that
the higher survival rates of African catfish larvae under dark conditions are a result of inactivity
and subsequent increase in chemical releasing stimuli concentrations around inactive individuals
that triggers feeding behavior in nearby active catfish. Therefore, we recommend larval rearing of
African catfish in dark or dim conditions, as it improves catfish survival rates. |
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