ABSTRACT
Factors contributing to the observed stability of a local ecosystem with predator-prey interaction and competition between two sea star species of the genus Astropecten were investigated. Predation by Astropecten aranciacus eliminates about 0.5 – 1 % of the prey population A. bispinosus per day. Recruitment by settlement in this coexistence zone was never observed, but immigration from adjoining patches of the eelgrass Zostera marina was found to at least partially compensate loss due to predation. Other possible refuge zones from which immigration may take place are discussed.
