Observations of Fry Cannibalism in <i>Clarias gariepinus</i>(Burchell, 1822)

EMBRYONIC AND LARVAL DEVELOPMENT OF A RED STRAIN OF THE EGYPTIAN AFRICAN CATFISH (Clarias gariepinus Burchell, 1822)

“…However, the growth performances in the next rearing phases still needed to be investigated. While many publications reported that cannibalism was common in larvae of C. gariepinus (Hecht & Appelbaum, 1987;Pienaar, 1990;Appelbaum & Kamler, 2000;Aluko et al, 2001;Baras & d'Almeida, 2001), in the present study cannibalism was not observed in larvae of Egyptian African catfish reared for 21 days period, either for the red or black strains, thereby resulted in high survival rate, ranged 92%-95%. Larval mortalities occurred due to other causes, presumably due to pathogenic infection of unhealthy weak larvae, morphological abnormality condition of the larvae, which died at third and fourth days, and also the feeding incapability (the hunger), assigned by the retained small sizes (no growth in length) of the larvae having exhausted yolk sac, which died at seventh and eighth days.…”

“…Those absences of cannibalism were thought as a result of the relatively uniform size of the larvae (coefficient of variation of the total length during those larval period ranged 1.90%-6.02% for the red strain and ranged 1.06%-6.01% in the black strain) and consistent availability of the feed. Results of the studies by Pienaar (1990) and Aluko et al (2001) suggested that feed availability, stocking density, and size variation affecting cannibalism on the larvae of C. gariepinus. However, results of the present study by using much higher stocking density (100 larvae/ liter) than those of both studies (ranged 0.03-18.18 larvae/liter, recalculated from the data reported by Pienaar, 1990 andAluko et al, 2001) revealed no cannibalism observed.…”

“…Results of the studies by Pienaar (1990) and Aluko et al (2001) suggested that feed availability, stocking density, and size variation affecting cannibalism on the larvae of C. gariepinus. However, results of the present study by using much higher stocking density (100 larvae/ liter) than those of both studies (ranged 0.03-18.18 larvae/liter, recalculated from the data reported by Pienaar, 1990 andAluko et al, 2001) revealed no cannibalism observed. Baras & d'Almeida (2001) in their study by using stocking densities of 100 and 200 larvae/liter also concluded that roles of the stocking densities in shaping cannibalism on the larvae of C. gariepinus were insignificant.…”

Implications of Size Heterogeneity and Food Availability on the Survival of Heterobranchus Longifilis Fingerlings

“…The result of the main effect of feeding frequencies viz-a-viz food availability in this experiment indicated that twice feeding produced a maximum of 74% survival while any lower frequency produced dismal result.This could be supported by Aluko et al [36] report that food availability appeared to be a major factor affecting cannibalism in Clarias gariepinus. Twice daily feeding in the present work ensured more food availability than once daily feeding or once in four days.…”