Study of fish exploitation pattern of lake Gerio, Yola, Adamawa State, Nigeria

Lack of exploratory data for effective stock management, negligence on the part of the regulatory bodies with regards to data collection have made clear impossible to know precisely how much fish is taken from lake Geriyo daily, monthly, or annually and this has led to decline in the fisheries yield and reduction in the livelihood of the fishermen in this community. An investigation was carried out on Lake Geriyo between the months of April and July 2010 to know the pattern of fish exploitation. A total of fourteen (14) species of thirteen (13) families were identified during the period. The family Claridae is the only family with two species while the other families had only one specie. Mormyrus species were found to have the highest percentage (27.7%) by number while Clarias species had the lowest of 7.54%. The total numbers of species were 1140 species and the corresponding total weights were 198 kg. In the course of the study, fishermen used unregulated mesh sized less than 2 inches. And most of the fish caught were undersized ranging from 0.06 kg to 0.78 kg. The mean catch per unit effort is 3.67. The correlation coefficient, r=0.734 which shows that there is a high correlation between the effort and the yield. The Yield (y)=11.143+3.560 effort which is an evidence of overfishing.