Assessment of the influence of limnological factors on the malacofauna of two major man made lakes in Zaria, Nigeria

Abstract

A comparative survey of molluscs was carried out in two major man-made lakes, Bomo and Kubanni, in Zaria during the rainy and dry seasons of 2007 and 2008. This was done to determine the molluscan compositions as well as to assess the physicochemical factors that may influence the malacofauna of the two lakes. Four sampling stations were selected along a line transect across each lake for collection of aquatic molluscs and measurement of physicochemical factors. Living representatives of molluscs belonging to the indigenous families: Planorbidae; Biomphalaria pfefferi and Bulinus globosus: Hydrobiidae; Unionidae; Anodonta marginata, Viviparidae; Viviparus sp. and Thiaridae; Melanoides torulosa and M. maculata, were obtained with only Thiaridae and Unionidae occurring in both lakes. However, the family Hydrobiidae was absent in Kubanni lake while Planorbidae and Viviparidae were absent in Bomo lake. Analysis of variance showed the seasonal variation of the physicochemical factors in the two lakes to be similar. The differences in the molluscan compositions of the two lakes could be attributed to other factors than variations in the physicochemical factors prevalent in the two lakes. This study has shown that considering their relative small sizes, Bomo and Kubanni lakes can be considered to have rich malacofauna of indigenous species, which can be targets for conservation initiatives and probable reservoirs of snail- hosts of diseases of public health significance.

Keywords: Limnology, Freshwater molluscs, Distribution