Aspects of the Biology of Silver Catfish (Chrysichthys nigrodigitatus) in Nwaniba River, Southeast Nigeria

Abstract

The Aspects of the Biology of the Catfish (Chrysichthys nigrodigitatus) were investigated from August to October 2015 in Nwaniba River, Akwa Ibom State, Nigeria. A total of two hundred (200) specimens were analyzed for gut contents using Numerical and Frequency of Occurrence methods. The results revealed that the species feed on various food items ranging from plant origin to animal materials with dietary preference classified into eight major groups consisting of Crustaceans 39 (23.2%), Fish parts 26 (15.6%), Detritus 23 (13.7%), Plant parts 20 (11.9%), Undefined 20 (11.9%), Mollusca 19 (11.3%), Insects 13 (7.7%), and Nematodes 8 (4.7%) respectively. Of the 200 stomachs examined, 35 (17.5%) were empty stomachs, 80 (40%) had quarter-full stomachs, 50 (25%) had half-full stomachs, 13 (6.5%) had three quarter-full stomachs and 22 (11%) had full stomachs. The condition factor calculated for the species varied during the studies period with a mean value of 0.77 in August, 0.72 in September and 0.73 in October. Based on the food items isolated in the gut, the species could be considered as an Omnivorous fish in Nwaniba River. Further research should be done to ascertain the food preference of the species over a longer period of time covering both wet and dry season. This will enable definite conclusion on its food preference.