The effect of sun‐drying on the infestation of the African catfish (Clarias gariepinus) by post‐harvest insects in the Lake Chad district of Nigeria

Abstract

Studies involving a survey of infestation of the African catfish, Clarias gariepinus (dried for 4 days and stored for more than 30 days), obtained from the fish market in Maiduguri, northeastern Nigeria, as well as the direct exposure of freshly caught catfish to three sun‐drying regimes, i.e. 1 day, 7 days and 14 days (stored for further 30 days under laboratory conditions) were carried out over a 5‐month period. Variations in weather conditions during the period were: daytime temperatures, 32–39.9°C; night temperatures, 23.1–27.7°C; and relatively humidity, 40–69%. There was a preponderance of dermestid larvae over adults and calliphorid maggots in fish samples dried for 4 days, 7 days and 14 days. Catfish dried for 1 day harboured significantly higher numbers of maggots compared with the numbers of dermestid larvae and adults. There were significant decreases in the numbers of maggots as drying time increased, suggesting a practical possibility for the protection of dried catfish against maggots with adequate pre‐storage drying and the maintenance of this moisture level during storage. There was also an inverse relationship between the proportions of maggots found in dried catfish with drying time but the number of dermestids increased with increased drying time. Dried catfish may not be protected against dermestids solely through sun‐drying.

Keywords:

• sun‐drying
• infestation
• African catfish
• post‐harvest
• insects

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