Effects of Artificial UVB Radiation on Growth, Survival, and Pigmentation of African Catfish (Clarias gariepinus) Fingerlings

Ultraviolet radiation B (UVB) is known to be detrimental to aquatic habitat; therefore, it's critical to understand how UVB affects Clarias gariepinus, which is widely cultured in Nigeria, in order to promote healthy growth of the fish. Two hundred fingerlings of the cat fish samples were obtained and divided into four equal groups, (A, B, C, and D) and kept in artificial ponds, and were respectively exposed to different UVB conditions [UVB-L (low)] 2.4 10-7 mW/cm2, UVB-M (moderate) 6.0 10-7 mW/cm2, UVB-H (high) 1.2 10-6 mW/cm2] and group D was used as a control. The exposure period was 16 days and 51 days, respectively for the short and long term. The results of short and long-term exposure depict that UVB-L does not cause significant changes to the sample, while UVB-M rapidly increases the weight and growth but decreases mortality rate of the cat fish sampled, and UVB-H retarded weight and growth but increases mortality rate of the Clarias gariepinus. The result on color change indicated that, the control, UVB-L, and UVB-M samples maintained their dark color throughout the period of the experiment, while UVB-H sample undergoes morphological and functional changes resulting in a complete change from dark to pink color. UVB-M was found to be highly beneficial to the cat fish for both short and long terms, it can therefore, be adopted by fish farmers to improve the healthy fish growth of their farm.