Cannibalistic behaviour of African catfish juveniles, clarias gariepinus under different light wavelengths and intensities

Abstract. The African catfish shows strong cannibalism during larval and juvenile stages. Environmental factor such as light illumination affect the cannibalistic behaviour of the fish, but the effect of light wavelengths towards African catfish behaviour is still unknown. Thus, the aim of this study was to investigate the effect of different light wavelengths and intensities towards the behaviour of African catfish juveniles. In this study, the juvenile’s behaviour was examined under five light wavelengths (white, blue, green, yellow and red) and four light intensities (0.0017, 0.021, 0.19, and 1.40 μmoles/m²/s). The results of the present study showed that the juveniles of African catfish had low biting activity under light intensities of 0.0017 and 0.021 μmoles/m²/s for white, blue, and yellow light wavelengths. Under light intensities of 0.19 and 1.40 μmoles/m²/s for blue and red light wavelengths, the juveniles of African catfish showed low biting activity. Only blue light wavelength showed low biting activity for all conditions of light intensities