THE REPRODUCTIVE CYCLE OF HELCION PRUINOSUS(PATELLOGASTROPODA) ON TWO SOUTH AFRICAN BOULDER SHORES

The reproductive cycle of the South African limpet Helcion pruinosus was determined over 19 months for a south-east and south-west coast population. Despite inhabiting shores subjected to different oceanographic conditions, limpets from both populations spawned mainly in summer with early gametogenesis occurring in spring. The gonads of limpets were never completely spent suggesting that they are partial spawners. The gonad index (G.I.) of males was significantly greater than that of females in both populations and the G.I. of south-west coast limpets greater than that of limpets from the south-east coast. The sex ratio of the population on the south-west coast was 1:1 whereas the south-east coast population contained significantly more males.