On the adaptation of the mussel Mytilus Edulis L. to different environmental suspended matter concentrations

There is evidence that dredging operations in coastal waters and estuaries lead to an increase of concentrations of suspended matter (SPM). Filterfeeding bivalves, such as Mytilus edulis, may adapt their feeding apparatus (gills and labial palps) to the ambient SPM levels. According to Theissen (1982) this adaptation in M. edulis has been determined genetically. This study reports on the variation of the relative dimensions of gills and labial palps of M. edulis in relation to SPM concentrations in the Dutch Wadden Sea and the adjacent North Sea. The results agree with those of Theissen (1982). Transplantations of M.edulis from Wadden Sea to North Sea and vice versa showed adaptations of the relative dimensions of the feeding apparatus to the changed SPM concentrations. It is therefore concluded that these adaptations are also phenotypically.