Evaluation of Physico-Chemical Water Quality, Length-Weight Relationship and Condition Factor of Fish Species Inhabiting Thomas Reservoir, Kano, Nigeria

Abstract

Evaluation of quality of aquatic medium and the growth of fish stock unveil the level of well-being of any fisheries. This study investigated the current physico-chemical water parameters, length-weight relationship and condition factor of fish species inhabiting Thomas reservoir. Five physico-chemical parameters namely; Temperature, Dissolved oxygen (DO), pH, Electrical conductivity (EC) and Total Dissolved solids (TDS) of the reservoir’s surface water were tested in situ on monthly basis for 12 months at three stations using digital meters. Fish samples were also collected on monthly basis from catches of the local fishermen at two landing sites of the water body. Body weight of each sampled fish was measured in situ in grams and also total length in centimeter. Length-weight relationships (LWRs) analysis was conducted using the least square regression equation and the condition factor (K) was calculated. Analysis of the water parameters’ data indicated significant differences (p≤0.05) among monthly water parameters with clear indication of influence of changes in seasons. Nevertheless the result indicated the parameters falls within tolerable range fit for the well-being of freshwater fish. Ten fish species were identified from the Reservoir. All the species exhibited negative allometric growth pattern except Sarotherodon galillaus with positive allometry (b=5.6) in the wet season. All the species during dry and wet seasons exhibited K values above ‘1’ except for Lates niloticus and Protopterus annectens. It is recommended that more ecological and biodiversity studies be conducted for detail information needed for efficient fisheries management of the reservoir.