A study of Intra-cohort Cannibalism in Juveniles of the African Catfish, (Clarias gariepinus) under Controlled Conditions

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Author(s) Obirikorang, K.A | Madkour, H.A | Adjei-Boateng, D
Pages 23-26
Volume 3
Issue 1
Date January, 2014
Keywords Intra-cohort, Cannibalism, African catfish, Clarias gariepinus, full-sibling group
Abstract

This laboratory study was conducted to study the phenomenon of intra-cohort cannibalism among juveniles of the African catfish (Clarias gariepinus) of the same full-sibling group (pure progenies). At the start of the 8-week experiment, each catfish fingerling weighed approximately 10g. The fingerlings were randomly assigned to two 80-litre aquaria (Tank 1 and Tank 2) at a stocking density of 20 fingerlings per tank. Mean weight of the fingerlings in tanks 1 and 2 at the end of the study were 52.65g ±5.21g and 73.27 ±15.15g. There was uniform weight gain among all the fingerlings in the two tanks, with the exception of one fingerling, which recorded a significant differential growth of 93.90g. This high individual growth resulted in the higher mean final weight recorded in tank 2. The size disparity between the relatively larger fingerling that exhibited the abnormal growth pattern and the other fingerlings resulted in more than half of the mortality due to cannibalism (58.3%) in tank 2. Group cannibalism among relatively similar size classes was however, the commonest form of cannibalism within the two tanks, representing 58.82% of the total cannibalism recorded during the study. Overall it is clear from the study that cannibalism in juvenile catfishes cannot be completely eliminated just by adequate feeding although its rate can certainly be reduced.

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