Interreg Safeguard - Food safety mapping of mussels and oysters (Crassostrea gigas) in the Dutch Wadden Sea

The areal coverage and biomass of the invasive Pacific oyster has increased in both the Dutch and German part of the Wadden Sea area since its introduction in the late seventies. In the Dutch part of the Wadden Sea oyster beds have increased in areal coverage in the period 2003 –2008. The Pacific oyster has relevance for commercial exploitation since 2009. This arises special interest for food safety aspects. A joint monitor program named ‘Interreg Safeguard’ has been set up with German partners to firstly identify oyster bed location and subsequently obtain insight in the temporal and areal variation in both the level of chemical contamination as well as contamination with pathogens. Measured levels were compared with legislation standards currently in force and it was also researched what the relation of pollution levels found in oysters were with those found in mussels collected in the near vicinity. This report describes the results of the work carried within the Dutch part of the Wadden Sea and include; results of the mapping effort of oyster beds, concentrations of chemical and microbiological parameters in oyster and mussel tissue and the comparison of the contaminant levels found in oyster with those found in mussels.