Shellfish
BY NICKI HOLMYARD
DEEP waters
Initiatives aimed at restoring native oysters are making good progress in Britain and the US
N
a�ve oyster (Ostrea edulis) popula�ons in the UK have declined by 95% since the mid 19th century, due to overfishing, pollu�on, the introduc�on of invasive species and disease. As a result, na�ve oyster reefs are one of the most threatened marine habitats in Europe. World-wide, oyster reefs are also imperilled, with an es�mated 85% loss in recent �mes. In the past few decades, the economic and environmental importance of na�ve oysters has become recognised, par�cularly their ability to improve water quality, provide nursery areas and habitat for other species, reduce nitrogen levels in the water, and sequester carbon in their shells. This has led to the se�ng up of a wide range of oyster enhancement and restora�on projects. Oysters and whisky The Na�ve Oyster Network, a community of academics, conserva�onists, oystermen and NGOs, is one body working to restore self-sustaining popula�ons of na�ve oysters in the UK and Ireland by suppor�ng the growing need of the species, its habitat and those working to restore O. edulis in Europe. The Na�ve Oyster Restora�on Alliance (NORA) is another. This organisa�on works to overcome exis�ng barriers to the conserva�on, restora�on and recovery of the European oyster by providing a pla�orm for collabora�on and par�cipa�on in knowledge exchange.
34
shellfish-final.indd 34
In Scotland, the Dornoch Environmental Enhancement Project (DEEP), ini�ated by the Glenmorangie Dis�llery with a team of scien�sts from Heriot-Wa� University, has just reported reaching a significant milestone in its efforts to restore a na�ve oyster reef to the Dornoch Firth. Oysters became ex�nct in the Firth more than 100 years ago, but in August 2021 the project team announced that 20,000 na�ve oysters had now been placed in the water. It is hoped that the success of the work will pave the way for the complete restora�on of the reef. The aim is to see four million oysters living there. The oysters are intended to play a key role in purifying the waters of the Dornoch Firth, which contains organic byproducts from the dis�llery, as each oyster can filter 200 litres of water per day. An anaerobic diges�on plant commissioned in 2017 reduces the dis�llery’s biological effluent load by around 95%, and the oyster reef is expected to soak up the remaining 5%. The DEEP team is also inves�ga�ng whether the restored oyster reef habitat has the capacity to act as a long-term carbon store. “DEEP has enabled us to demonstrate the many benefits of restora�on of long-lost reefs, and car-
We are s�ll uncovering exactly how “ much of a game changer this could be ”
www.fishfarmermagazine.com
13/09/2021 15:28:58
