Short Communication

Survival strategies of sharptooth catfish Clarias gariepinus in desiccating pans in the northern Kruger National Park

B.C.W. Van der Waal
Koedoe | Vol 41, No 2 | a258 | DOI: https://doi.org/10.4102/koedoe.v41i2.258 | © 1998 B.C.W. Van der Waal | This work is licensed under CC Attribution 4.0
Submitted: 01 August 1998 | Published: 01 August 1998

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B.C.W. Van der Waal, University of Venda, South Africa

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Abstract

Observations in drying out pans showed that small (26-37 cm) sharptooth catfish (Clarias gariepinus) can hide at the bottom of small pools filled with sticky mud whereas larger fish stay afloat at the surface in larger pools with sloppy mud, where they easily become prey or succumb to heat stress. The inability of larger fish to keep down in the sloppy mud of up to 40 cm depth is the result of their large bulk and high density of the mud. This may indicate a survival advantage for smaller fish in the final dry-out phase of pools and is supported by the presence of only small fish remains in the last drying up pools of dry pans. Another adaptation of smaller fish includes the temporary congregation outside the water enabling concealment under dense vegetation as a means to escape adverse environmental conditions, including high water temperatures and avian predation. The advantage small fish have over larger catfish under these extreme conditions may explain why catfish are known to show a wide variation in growth rate under natural and aquaculture conditions.

Keywords

catfish, Clarias gariepinus, desiccation, survival strategies

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Crossref Citations

1. Size distribution in African catfish (Clarias gariepinus) affects feeding behaviour but not growth
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Aquaculture  vol: 250  issue: 1-2  first page: 300  year: 2005  
doi: 10.1016/j.aquaculture.2005.05.034