Aspects of Ecology of Clarias anguillaris (Teleostei: Clariidae) in the Cross River, Nigeria

Yıl 2010, Cilt: 10 Sayı: 1, - , 01.02.2010

Benedict Obeten Offem Yemi Akegbejo-samsons Isaac Tonde Omoniyi

Öz

The life history of Clarias anguillaris was studied over 24 months in the upper, middle and lower reaches of the 200 km length of Cross River, Nigeria. The influence of spatial and seasonal variables on the distribution and abundance, reproduction, diet and size was determined from catch samples over 24 months in the 200 km length of the Cross River, Nigeria. Fish occurred unevenly in the three reaches and over the dry and wet seasons, with peak abundances during the early and late rains and lower values in the upper reach than in the middle and lower reaches. Night catches were higher than day catches, with males being more common than females. The peak breeding period was June - July. The fish were omnivorous with trophic flexibility being related to food availability.Mean allometric coefficients in the three reaches indicated an isometric growth pattern. The condition of the fish was the same in the three reaches but declined during dry season and improved during early and late rains. Fish was therefore in better condition during the rainy season and was not affected by spatial changes.

Anahtar Kelimeler

distribution, abundance, fecundity, diet habit, length-weight relationship, condition factor, sex ratio, spatial variables, seasonal variables