Effects of sea stars and crabs on sea scallop Placopecten magellanicus recruitment in the Mid-Atlantic Bight (USA)

摘要

Relationships between recruitment of the Atlantic sea scallop Placopecten magellanicus and the abundances of 3 types of invertebrate predators, the sand star Astropecten americanus, the common sea stars Asterias spp. and the crabs Cancer spp., were investigated using data from large-scale scallop surveys in the Mid-Atlantic Bight (USA). Both asteroid groups appeared to reduce sea scallop recruitment, with significantly lower recruitment in areas where the sea stars were in high abundance. No significant effect of Cancer spp. crabs on scallop recruitment was detected. Very high densities of A. americanus, no sea scallop recruitment, and low Asterias spp. densities were observed in all stations with depths > 85 m, and in many stations between 65 and 85 m. Astropecten americanus may be a dominant component of the deep-water ( > 75 m) benthic community in the Mid-Atlantic Bight that is capable of excluding both sea scallops and Asterias spp. from areas where A. americanus are highly abundant.