Healthier bivalves, healthier shellfish industry
Oysters, mussels, clams... marine molluscs are valued as tasty sources of nutrients. They are also valuable sources of income for many regions. EU-funded research is developing new knowledge and innovative techniques to help tackle diseases that can affect the health of bivalves and the livelihoods of producers as well as consumer health.
© auremar #278009082 source: stock.adobe.com 2019
The EU-funded project VIVALDI, which focuses on farmed bivalves, is shedding new light on pathogens that can cause entire harvests to fail and devising innovative solutions to help reduce associated risks.
The objectives are to better understand the diseases, but also to develop tools and strategies to improve their prevention, mitigation and control, says project coordinator Isabelle Arzul of French National Institute for Ocean Science IFREMER.
VIVALDI has generated new knowledge about the pathogens, identifying several new ones in the process, designed new techniques for their detection, conducted breeding programmes to produce more resistant bivalves, and proposed innovative disease control solutions, Arzul notes.
As of October 2019, with four more months before the project is due to end, the partners are compiling new and existing guidance to produce recommendations for stakeholders.
In our project, we always have activities trying to improve our knowledge and more applied activities, where we try to develop solutions, Arzul explains. VIVALDIs work on bivalves natural defences, for example, includes measures on both fronts.
According to Arzul, molluscs are able to defend themselves against pathogens they are not as basic as they might seem. This self-protection capacity is an important aspect we would like to know more about. We are studying the mechanisms they have developed, and we try to use molecules that are known to stimulate immunity in other species to generate it in bivalves, she explains.
Apparently, this approach does seem to work. Along with breeding and selecting bivalves that are naturally more resistant to disease, it could be a way for hatcheries to produce animals that are more resilient, with better chances to thrive in the field.
Selective breeding could also open up opportunities to boost food safety by producing animals that accumulate fewer microbes likely to affect human health. Bivalves are vulnerable to diseases that are not usually harmful to consumers beyond the fact that spoiled shellfish should of course not be eaten, Arzul notes. However, they can be a reservoir of pathogens such as norovirus.
Further innovations proposed by VIVALDI include sensors to detect the presence of pathogens in the water. Previous research had typically focused on spotting pathogens in the molluscs. VIVALDI uses plastic membranes immersed in the water around the shellfish to monitor microbes, which could potentially be developed into an early-detection system, Arzul explains.
The partners have also developed a risk-ranking tool that estimates the likelihood of pathogens being introduced or disseminated in a specific location. This model, which can be used to assess the probability of contamination for individual shellfish farms or entire areas, can help to improve monitoring programmes.
Particular attention in the project focused on involving stakeholders, both to take stock of concerns and to raise awareness of new possibilities. We held focus groups that enabled us to interact with a variety of entities from several countries, Arzul explains. Shellfish production is organised very differently from one EU country to another, which has to be taken into account in disseminating recommendations on disease management.
Furthermore, VIVALDI is providing the right innovation to help increase capacity in the shellfish-production sector and is helping to improve best practices. The project will not only increase food safety but will also add value to the product and open new market opportunities.
The partners are also considering the après-VIVALDI. We already have new questions, says Arzul. Based on our results, we could now look into the impact of global change on shellfish production and notably on the emergence of new diseases, for example.
Furthermore, the knowledge and techniques delivered by VIVALDI could help to refine the restoration programmes deployed in different parts of Europe to revive populations of native species such as the flat oyster. The partners will also seek opportunities to inform potential upgrades of European legislation relevant to shellfish diseases, Arzul concludes.