A malacological survey was undertaken in the freshwater systems within Anambra River basin from July 2000 to June 2001. Three stations were selected within which 13 sites were studied. The survey revealed the presence of a rich molluscan fauna including those endemic in the basin alone. The species collected included 5 pulmonates and 12 prosobranchs (all gastropods). Otu Idoko was identified as the habitat having the richest snail fauna while the burrow pits at Mmiata had the lowest snail population. Habitat type, rainfall and desiccation had tremendous effects on the population dynamics of snails. Thus the highest density in flowing water habitats was recorded between July and September, whereas the highest density in stagnant pools was recorded in May to June. Other factors found to impact severely on the populations of snails causing visible fluctuation in their density include: electrical conductivity, dissolved oxygen, calcium ions and pH. Three genera: Pila, Lanistes and Bulinus were found to contain infected species. The dominant snails found in this basin were Pila and Potadoma species. The finding of Gabiella sp was the most exciting find as it is very rare in Nigerian waters. The findings were used to discuss the health implications for the people living and working in the basin area. Key Words: Malacological Survey, Freshwater Systems, Anambra State Bio-Research Vol.2(1) 2004: 29-38
FC Akafor, RN Obiezue
