Nicki Holmyard

BY NICKI HOLMYARD

DEEP waters

Initiatives aimed at restoring native oysters are making good progress in Britain and the US

Na� ve oyster (Ostrea edulis) popula� ons in the UK have declined by 95% since the mid 19th century, due to overfi shing, 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.

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 signifi cant milestone in its eff orts 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 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 fi lter 200 litres of water per day. An anaerobic diges� on plant commissioned in 2017 reduces the dis� llery’s biological effl uent 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 benefi ts of restora� on of long-lost reefs, and car-

“We are s� ll uncovering exactly how much of a game changer this could be”

Opposite from top: Professor Bill Sanderson; DEEP project diver scien� st dives into the Dornoch Firth

This page from top: HWU scien� st team and Hamish Torrie, CSR Communica� ons Director at Glenmorangie; Na� ve European oysters from the Dornoch Firth project; Billion Oyster Project, New York City; (L-R) Alex Robertson-Jones and Prof Bill Sanderson bon storage is yet another exci� ng outcome of our research. We are s� ll uncovering exactly how much of a game changer this could be, but we’re increasingly focusing our research on delving deeper into the role of the oyster reef as a carbon store,” Professor Bill Sanderson of Heriot-Wa� University says.

Professor John Baxter, Chair of DEEP’s Research Advisory Panel, explains that the DEEP research is helping to set the standard in all aspects of marine habitat restora� on work, such as biosecurity and monitoring.

“As we embark on the UN Decade on Ecosystem Restora� on (2021-2030) DEEP is a prime example of the mul� ple benefi ts that can come from such ini� a� ves,” he says.

The UN Decade on Ecosystem Restora� on has been hailed as a “global rallying cry to heal our planet”. It aims to prevent, halt and reverse the degrada� on of ecosystems on every con� nent and in every ocean, and help to end poverty, combat climate change and prevent a mass ex� nc� on.

Thomas Moradpour, CEO and President of the Glenmorangie Company, believes that all businesses should play their part in enhancing the environment, leaving it in be� er shape for the next genera� on. He is pleased that his company is making a diff erence with the project.

The Sco� sh oyster industry has benefi ted hugely from DEEP’s demand for the na� ve European oyster. Recognising the need for a sustainable supply chain to aid restora� on eff orts in the Dornoch Firth, Glenmorangie and its partners have formed close working rela� onships with UK shellfi sh growers, who are helping to grow the juvenile oysters needed for the project.

It is hoped that the industry could posi� on itself to supply the 50 million oysters needed for all of Europe’s exis� ng reef restora� on projects, and in the longer term to supply restaurants across the world.

Ambi� ons for Wales

Na� ve oysters are also being restored to North Wales waters in an ambi� ous project that aims to bring them back from the brink of ex� nc� on in the River Conwy.

Oysters thrived in the local area in the 18th and 19th centuries, forming an important part of the local marine ecosystem. Boats reported landing up to 8,000 shells per day. Since their disappearance, the important role they played in helping to clean the river and act as an important habitat for marine wildlife has been lost.

More than 1,300 oysters have now been suspended beneath pontoons in the Conwy and Deganwy Marinas to create a microhabitat that will act as a maternity ward for the next genera� on of oysters.

They will also act as an outdoor classroom for local schoolchildren, students and ci� zen scien� sts, and provide a window into the ocean to inspire the next genera� on to protect and care for the marine environment

The Wild Oysters Project is a partnership between Zoological Society of London (ZSL), Blue Marine Founda� on (BLUE) and Bri� sh Marine. Bangor University’s School of Ocean Sciences and a local project offi cer are monitoring progress.

“Conwy Bay is a designated Special Area of Conserva� on, with unique underwater habitats and important marine plants and wildlife. We hope that the project will help to create cleaner water, healthier fi sheries and plen� ful marine biodiversity,” Celine Gamble, Wild Oysters Project Manager, ZSL, says.

One billion oysters for New York

Across the Atlan� c, the Billion Oyster Project, a ci� zen science project co-ordinated by the New York Harbor School with the goal of restoring one billion live oysters to New York Harbor by 2035, is making good progress. The project already has more than 10,000 volunteers who share the determina� on of the founders, Murray Fisher and Pete Malinowski, to return a healthy, biodiverse harbour to New York. It also aims to engage hundreds of thousands of schoolchildren during its life� me in marine restora� on-based STEM educa� on programmes. “Restoring oysters to one of the busiest ports in the United States is par� cularly challenging, but we have an amazing team and a dedicated community behind us,” Fisher says. FF