Influence of Water Quality on the Abundance of Freshwater Mollusc in Biase, Cross River State, South-Eastern Nigeria

The study on the distribution, diversity and abundance of freshwater mollusc in Biase Local Government Area was carried-out over a period of 3 months; July – September 2017. Mollusc were collected using a mesh scoop method, then put in a well labelled plastic container and preserved appropriately, before they were sorted and identified to species level in the laboratory using the freshwater mollusc identification guide. A total of 652 individuals of freshwater mollusc belonging to Ampullariidae, Thiaridae and Margaritiferidae families were observed through-out the study. Four species of fresh water mollusc were observed namely; Lanistes ovum, Lanistes libycus, Melanoides tuberculata and Margaritifera margaritifera. Ampullariidae family was the most abundant (475 individuals), while the Thiaridae family was the least abundant (27 individuals). Lanistes libycus was the most abundant species (290 individuals). The abundance of fresh water mollusc varied across sampling stations. The Shannon Weinner, equitability and Margalef index were generally lower than 1 and varied across all the sampling stations. The pH, temperature and dissolved oxygen varied insignificantly across the 4 sampling stations at p>0.05. There is a need for Government to enforce policies and laws against careless discharge of energies and waste into the study area and over-exploitation of these resources, so as to restore the ecosystem back to its normal quality, as well as prevent possible extinction of these resources. More of similar research should also be carried out regularly, so as to monitor any possible improvement in terms of species abundance and water quality.