Distribution and abundance of freshwater snails in Warwade Dam, Dutse, Northern Nigeria

Preliminary investigation in August, 2017 reported the presence of Lymnaea natalensis, Bellamya unicolor, Melanoides tuberculata and Bulinus globosus in order of increasing abundance and distribution in Warwade dam, Dutse, Jigawa State, Nigeria. A follow up study was carried out from April to October, 2019 to reveal further details on the abundance and distribution of freshwater snails in relation to some physiochemical factors of the dam. Four sampling sites; human activity, vegetation cover, lentic and lotic were selected for the study along the bank of the dam. Freshwater snails were collected using long handled scoop net with mesh 0.2mm complemented by hand picking methods in the four sampling sites. Water samples from the sampling sites were analyzed in the laboratory using standard procedures. A total of 2,027 of freshwater snails belonging to ten species were identified. Bulinus globosus 12(0.6%) and Lymnaea natalensis 12(0.6%) had the lowest abundance and distribution while Melanoides tuberculata 1553(76.6%) had the highest. Snail abundance was highest in site characterized by human activities (670) followed by vegetation (482), lotic (442) and lentic (433) waters. Most of the physico-chemical factors measured appeared to favour the growth and survival of fresh water snails. pH (p = 0.01), water current (p = <0.01) and magnesium ion concentration (p = < 0.01) varied significantly across the four sites. Only calcium ion concentration was significantly associated with snail abundance (p = 0.04). Snail abundance showed weak positive relationship with water temperature, color, turbidity and concentration of magnesium ion. The dam habours about ten species of freshwater snails in different abundance and distribution with M. tuberculata being the most abundant throughout the period of investigation. The dominance of M. tuberculata over other species particularly those of medical and veterinary importance could have positive implication for their control in the dam