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Seehagen, A., S. Gollasch, H. Rosenthal, 2001. The Interspecific Competition between Carcinus maenas Linnaeus 1758 and Hemigrapsus penicillatus (De Haan 1835), a Potential Invader into German Coastal Waters, Institut für Meereskunde an der Universität. Proceedings of the Second International Conference on Marine Bioinvasions, New Orleans, La., April 9-11, 2001, p. 57. The Interspecific Competition between Carcinus maenas Linnaeus 1758 and Hemigrapsus penicillatus (De Haan 1835), a Potential Invader into German Coastal WatersThe interspecific competition between two species of decapod crabs Carcinus maenas (Linnaeus 1758), native to Europe, and Hemigrapsus penicillatus (De Haan 1835), native to Asia and introduced to Europe, was studied under laboratory conditions. Both species prefer similar habitats and tolerate high temperature and salinity variations. Crabs were collected from the German North Sea coast (C. maenas) and French Atlantic coast (H. penicillatus). Two methods were followed to describe an interspecific competition. First, interspecific distances maintained between individuals of both species was tested at different ratios of both species under different temperature and salinity combinations. Second, the effect of crevices as a factor to reduce interspecific competition for space was investigated. The experiments showed that a relatively large distance was maintained between C. maenas and H. penicillatus. The stocking ratio of both species as well as the temperature had a clear effect on interspecific distances. When offered, both species preferred to use hiding places frequently. In presence of the other species no change in behavior was observed. This was independent of the temperature or salinity. To sum up, it can be said that an interspecific competition exists for space between C. maenas and H. penicillatus. Relative high mortality of C. maenas observed in the presence of H. penicillatus suggests that the Asian decapod has the potential to dominate the native C. maenas. Contact: Annett Seehagen, Marine Okologie, Institut für Meereskunde an der Universität, Fachbereich 3, Düsternbrooker, Weg 20, D-24105 Kiel, GERMANY |