Reproduction, recruitment and juvenile ecology of the starfish,Asterias rubensandMarthasterias glacialis

Abstract

Reproductive cycles are described for subtidal and intertidal populations of the, starfishAsterias rubensL. and for a subtidal population of the starfishMarthasterias glacialisL. on the south-west coast of Britain. IntertidalA. rubenshad a clearly defined reproductive cycle with spring-early summer spawning. Pyloric caecum indices were inversely related to gonad indices. SubtidalA. rubenshad lower gonad indices and less seasonal variation in the pyloric caecum indices. Gonad indices ofM. glacialissuggest few animals in the population studied were breeding, but it is likely that this species also spawns in summer.Plankton samples and larval rearing studies suggest a planktotrophic pelagic life of approximately 90 days forA. rubens. Field observations and laboratory experiments show larvae settle on a wide range of substrata. Recruitment to an intertidal population ofA. rubensat Hollicombe Reef occurred in July 1980 and September 1981. Growth of juvenile starfish was followed for 17 months. Juvenile starfish feed carnivorously at the completion of metamorphosis. Early growth is rapid; however, there is a reduction in the growth rate during winter months. Feeding and growth of juvenileA. rubensis compared with published data on juvenile starfish of other species.