Influence of dark-rearing on the ontogenetic development of Sarotherodon mossambicus (Cichlidae, Teleostei): I. Effects on body weight, body growth pattern, swimming activity and visual acuity.
The ontogenesis of the cichlid fish, Sarotherodon mossambicus was investigated under normal- and dark-rearing conditions from hatching to 100 days. Light deprivation did not change normal increase in body weight. The increase in body length was slightly retarded in dark-reared animals (DR), whereas the increase in body height was more pronounced as compared to normal-reared animals (NR). DR failed to swim up after resorption of the yolk sack. Visual acuity was severely impaired. The first deficits in visual discrimination were observed after 20-30 days in the dark. After 50 days DR failed to show any optokinetic nystagmus.
D000818:Animals; D001835:Body Weight; D003624:Darkness; D005123:Eye / Q000254:growth & development; D005399:Fishes / Q000254:growth & development*; D009043:Motor Activity / Q000502:physiology*; D014792:Visual Acuity