Objective: To assess the impact of Muschovy ducks on snail populations.
Design: Populations of four different snail species were monitored in nine ponds for a period of 32 weeks. Zero, one and two ducks were randomly introduced to a set of three ponds in the 16th, 20th and 24th week.
Setting: Nine fenced ponds at De Beers Research Laboratory, Chiredzi.
Main outcome measures: Reduction in snail population following introduction of ducks.
Results: Mean counts for the intervention period showed that more intermediate host snails (Bulinus globosus and Biomphalaria pfeifferi) were present in ponds where ducks were not introduced (control) than in ponds where either one or two ducks were introduced. In control ponds the mean counts for intermediate host snails were 1.37, 1.03 and 1.02 for control, treatment with one duck and treatment with two ducks respectively. Similar observations were made for Physa acuta, with mean counts of 1.10, 0.64 and 0.67 for control, treatment with one duck and treatment with two ducks, respectively. No differences were observed in snail counts of Melanoides turbeculata where 2.40 snails were collected from the control pond and 2.37 snails in both treatment ponds. There was no significant difference in number of snails in ponds with one or two ducks.
Conclusion: The study demonstrated that Muschovy ducks significantly reduce snail populations in a pond environment. Further studies are required in large natural ponds before conclusive recommendations are made on the use of Muschovy ducks as biological control agents of schistosomiasis intermediate host snails can be drawn.