Catch assessment of Tilapia zillii in Ogun Estuary, Ogun State, Nigeria

Abstract

A study on catch assessment of T. zillii was carried out in Ogun estuary located between Ogun Water side and Ijebu East Local Government Area, Ogun State, Nigeria. The lagoon was stratified based on homogenous fishing activities. Fish catches were randomly assessed from commercial landings at selected landing sites. Data were collected on length-frequency distribution, catch landings and water quality parameters. Length-frequency distribution showed that the size of T. zillii ranged from 11cm to 37cm with observed weight range, 38.0g – 115.0g. Annual catch landing was 274,333.33kg. The monthly catches ranged from 12264.29kg in March to 39379.36kg in July. There was significant difference (P<0.05) between the monthly catch landings of T. zillii at selected sites on the estuary. These variations were influenced by the gears used in exploiting the resource and the season of the year. There was no significant difference (P>0.05) between the seasonal mean values of temperature, salinity and pH of water measured. For other water quality parameters, conductivity, dissolved oxygen and phosphate, values were significantly higher (P < 0.05) during the wet season than the dry season. Measured water quality parameters showed no significant correlation (P>0.05) with annual fish yield in the fishery.