Predator-Prey Interaction between two Competing Sea Star Species of the Genus Astropecten |
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Authors: | Paul H Schmid Rolf Schaerer |
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Institution: | Zoologisches Museum der Universität Zürich, Winterthurerstraße 190. CH-8057 Zürich |
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Abstract: | Abstract. The predator-prey interaction between two sea star species of the genus Astropecten known to be competitors was investigated at Costa Colostrai, Sardinia, Italy by means of SCUBA-Diving. It was estimated that predation of A. aranciacus would eliminate about 1 % of the prey population of A. bispinosus daily. Because densities of A. bispinosus were observed to be unaltered during the summer months, a considerable immigration of A. bispinosus into the area has to be postulated. A. bispinosus represents 40% of the dry organic matter consumed by A. aranciacus , and is one of the most important food items of this species. A. aranciacus is not more efficient in preying upon A. bispinosus than in preying upon other food items; but efficiency is greater upon buried sea stars than upon walking ones. Consequences for stability of the local ecosystem are discussed. |
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Keywords: | Predation interference competition food comsumption efficiency stability Astropecten Mediterranean Sea |
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