Length-weight relationship, condition factor and sex ratio of Protopterus annectens in Goronyo reservoir , Sokoto, Nigeria

Abstract

The study was conducted to investigate the length-weight relationship, condition factor and sex ratio of West African lungfish Protopterus annectens (Owen), in Goronyo reservoir north western Nigeria. 128 fish samples were collected from the Rimawa landing site of Goronyo reservoir for a period of three months. Samples were collected weekly from the fishermen from the month of September to November 2019, and the samples were examined fresh, while those that could not be treated immediately were preserved in a freezer until the next day. The total length of the fish samples ranged from 20.0com to 56.0cm and the total weight ranged from 30.5g to 510.7g. the mean condition factor ranged from from 0.33 to 0.40 throughout the study period while the overall mean sex ratio was 1.13:1 male to females. The result of this study demonstrated that the condition factor of P. annectens is <1 procured in this study revealed that the species are not in good condition throughout the study period. In terms of growth pattern Protopterus annectens also exhibits a negative allometric growth pattern, which means the fish grows more in length than in weight, the rate of increase in body length is not proportional to the increase in body weight. The sex ratio in this study shows that the males are more numerous than the females in the study area.