DNA identification of shellfish species and hybrids (KB-36-002-036)

In the annual shellfish surveys in Dutch coastal waters certain species are difficult to distinguish from each other based on visual identification characteristics alone. These are the common and lagoon cockle (C. edule & C. glaucum) and the Manila clam (R. philippinarum) and indigenous carpet shells (R. decussatus & V. corrugata). The latter often have to be identified based on their siphons alone. Both sets of species appear to show intermediate identification characteristics and may interbreed leading to hybrid forms. In order to reduce a potential error in stock assessments of the commercially important C. edule and R. philippinarum we propose to study whether these species hybridize in Dutch coastal waters and to improve identification keys, also for siphons only. We will use a combination of traditional identification methods and DNA analyses.