To date, there are virtually no studies where the competitive interactions between benthic and pelagic species are experimentally evaluated although such benthic–pelagic coupling might be relevant in many instances. In this study we investigated if Hediste diversicolor and Neomysis integer compete with each other for space and food during May–June when the densities of both species are very high in the shallow bays of the northern Baltic Sea. The interspecific interactions between the test organisms were studied in small plastic buckets placed on the seafloor in a shallow (2 m) bay. Experiments showed that H. diversicolor was competitively superior over N. integer. At a low food level the competitive interactions reduced the survival of N. integer whereas at a high food level no such negative effects were observed.
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