BUFFER ZONES: Tracking norovirus and marine biotoxins in the marine environment to select appropriate areas for shellfish farming and protect consumers
by Carlos Campos (Cefas), Gary Rawle (Westcountry Mussels of Fowey) & Jorge Diogene (IRTA), SEAFOODTOMORROW Partners
Bivalve shellfish (such as oysters and mussels) are nutritious, delicious food. When grown in coastal areas, shellfish can be occasionally exposed to pollutants and accumulate norovirus (NoV), marine biotoxins and other noxious substances. Commercial production of shellfish therefore needs to ensure that these potential health risks are satisfactorily addressed, through appropriate choice of production area and adequate processing, so that the consumers can enjoy eating a safe final product.
Within SEAFOODTOMORROW, project partner Cefas (UK) is collaborating with IRTA (Spain) and Westcountry Mussels of Fowey (WCM, UK) on the development of mathematical models for prediction of NoV and toxins in shellfish based on environmental data. To develop these models, the research team is undertaking field studies to obtain data on environmental microbiology, water circulation and pollution source tracing, and will also consider information from satellite imagery.
The team will then produce maps to illustrate the environmental conditions under which it is safe to harvest shellfish. Preliminary results show that the dilution of sewage effluents is inversely correlated with the levels of NoV in the shellfish  and that biological and environmental data can be used to predict the presence of some species of phytoplankton that produce toxins with one-week notice . The project team hope to develop and validate this model to ensure that it can be applied across Europe and anticipate that this work will contribute to greater public health protection by allowing shellfish to be harvested only from waters of high quality.
Figure caption: (A) Rhodamine dye fluorescence will be measured in the rivers after dye release to provide quantitative data on sewage dilution. (B) Shellfish will be sampled and tested for E. coli, norovirus and bacteriophage. (C) Turbidity fields will be identified from high-resolution Landsat 8 imagery to describe how river plumes interact with the receiving waters. (D) Buffer zones will be simulated for different environmental conditions to advise shellfish farmers on likely risk of contamination.