The lungfish Protopterus annectans (Owen) as a biocontrol agent against schistosome vector snails

Laboratory and small-scale field experiments have been carried out to study the malacophagous capabilities of the lungfish Protopterus annectans. When individual fish were offered a range of aquatic fauna in aquaria in the laboratory only snails and dragonfly larvae were consumed. When offered a choice, the fish appeared to prefer snails, with larger individuals (up to 300 mm) capable of consuming up to 200 snails per day. The introduction of five P. annectans into a small concrete pond (diameter 5 m) with an established fauna and flora resulted in a reduction in the snail population of over 90% within 2 weeks. This reduction was maintained over a 4-month observation period suggesting that in habitats in which the lungfish can survive, there is a possibility of significant snail control.