EU Shellfish Aquaculture Improves Water Quality, Study Shows

European shellfish aquaculture can help reduce negative water quality impacts of excess nutrients (nitrogen and phosphorus) in coastal communities, according to a recent study funded by the European Union’s Horizon 2020 programme. The study, conducted by a multi-national team during the GAIN project (Green Aquaculture Intensification in Europe http://www.unive.it/gainh2020_eu) examined the potential for including aquaculture of mussels, oysters, and clams in watershed-scale nutrient management policies.

Nutrient discharges to coastal waterbodies can stimulate excessive growth of algae leading to water quality degradation with consequences such as low oxygen, dead fish, and/or harmful algal blooms. These nutrient-related impacts have been reported for many EU estuaries.

Ria de Vigo, Spain. Panoramic view from O Morrazo.

Nutrient pollution, or eutrophication, is typically controlled by  preventing nutrient discharges to coastal waters through management measures including wastewater treatment and careful use of agriculture fertilizer. Wastewater treatment has been very successful in reducing direct loads, but reductions that require major changes in agriculture, livestock, and community management are economically costly and may have severe social consequences.

Growing bivalve shellfish provides direct economic benefits to a community by supporting jobs and making local seafood available to consumers. It also provides ecosystem services—benefits that nature provides to people—including reductions of algae, which are eaten by the clams, oysters and mussels. The shellfish absorb nutrients into their tissue and shell and remove algae and nutrients from the waterbody, contributing to the environmental sustainability of estuaries, bays, and coastal zones.

Panoramic view of Ria de Vigo.

The removal of algae by filter-feeding bivalve shellfish is an important and economically valuable ecosystem service—in the USA, compensation to shellfish farmers for the water clearance service they provide is at an advanced stage of debate; in the Chesapeake Bay, growers have been paid for services provided by oyster aquaculture.

Results of this study will provide the basis for strategic guidelines to develop a nutrient credit trading programme in Europe. Our study shows that EU annual production of over half a million metric tons of bivalves removes between 5 and 13 thousand tons of nitrogen per year. The annual cost of removing the same amount of nutrients using other measures would be between 18 and 48 billion €.

Bateas, Vigo, Spain

“Our hope is that our approach will be useful throughout the EU, and that our positive results will help inform discussions about the value of shellfish aquaculture to water quality, in addition to seafood provision,” said Prof. Roberto Pastres, coordinator of the GAIN project.

Prof. Pastres added “We recommend the inclusion of bivalves within comprehensive nutrient management plans. Shellfish farming, with its reduced ecological footprint, net removal of organic material, and low food-web nutritional requirements, is perhaps the best example of nature-based intensification for blue growth.”

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Surrounded by innovation

By: Meredith Burke and Catilin Stockwell

Over the past few decades, technological advances have completely revolutionized our society. It has influenced the way we live our lives, from the way we watch TV, to the way we conduct our scientific research. However, the aquaculture industry has fallen by the wayside. Big data, collected and distributed to our hands in the form of apps, have begun to dominate our world, so why is this not the case in one of the fastest growing industries in the world?

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Farming fish with the Atlantic Canada in the background

Atlantic Canada has recently emerged as a global leader in ocean technology, as well as playing host to one of the largest aquaculture companies in the world, Cooke Aquaculture. We have the unique opportunity of being surrounded by innovation. We are able to work side by side with the developers, as well as the consumers, to field test new technologies, and optimize their performance prior to commercialization.

However, aquaculture is still a relatively young industry, often operating in remote places, so introducing the use of technology has been difficult. Through research projects, we have been able to merge two key industry partners: ocean technology via InnovaSea, and salmon aquaculture, through Cooke, in order to improve management practices.

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Meredith’s research focuses primarily on using real-time sensors to study water quality parameters, like oxygen and temperature, to understand how they vary through a farm, and what may influence these variations. At the same time, Caitlin uses acoustic telemetry to track fish movement in order to understand fish behaviour and improve welfare management. These two projects together allow us to provide a more holistic view of fish farming to create a more sustainable industry.

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We hope that our work will help inform other aquaculture industries throughout the world, to become more innovative, improve farming practices, and ultimately create happier and healthier fish, with the ability to feed a growing population.