Evidence for lacustrine breeding by sanjika Opsaridium microcephalum (Teleostei: Cyprinidae) in Lake Malawi

Three species of Opsaridium occur in the Lake Malawi catchment. The kabyabya Opsaridium tweddleorum is a small species restricted to inflowing rivers and streams, the mpasa Opsaridium microlepis is a large lake-dwelling species that ascends the lower reaches of inflowing rivers during the rains to spawn, and the sanjika Opsaridium microcephalum has riverine, potamodromous and lake spawning populations. Evidence for sanjika spawning in the lake itself, rather than just in rivers, is presented here in the form of observations of courting behaviour by fully mature males and females on exposed rocky shores, together with the presence of pin-head fry in areas remote from any inflowing streams during the dry season.