Length-weight relationship, condition factor and sex ratio of two chrysichthys species (pisces: claroteidae) of socio-economic importance from Kpong reservoir in Ghana

Abstract

A total of 392 combined samples of Chrysichthys auratus and Chrysichthys nigrodigitatus was obtained from experimental and artisanal fishing from inshore and offshore areas of Kpong Reservoir. C. auratus and C. nigrodigitatus exhibited hyperallometric (b = 3.17–3.23) and hypoallometric (b = 2.79 - 2.91) growth patterns, respectively. Fluctuating monthly condition factor for males, females and combined sexes observed for the two species based on standard length and total length could be attributed to changes in feeding activity and, or degree of nourishment, food availability, gonadal activity, and season. However, based on total length, October and June were periods of the best physiological condition for C. auratus, while for C. nigrodigitatus, December was the least physiological period. There were significantly more females than males while differences in sex ratio were significant at 95 percent confidence interval (P = 1.354), indicating departure from the expected sex ratio of 1:1 for the two species. Regular assessment of biological, ecological and environmental characteristics of the species is recommended to provide the requisite information for sustainable management of the species for reservoir fishery development and food security.