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Oyster restoration in the United States is decades ahead of Europe and much better funded, with significant funds coming from the government including the military, a BLUE fact-finding trip to the east and west coasts has shown. A small team of budding oyster restoration practitioners from Europe, the United States and Australia arrived in Washington DC in early June to start an intensive week-long oyster study tour of both Chesapeake Bay on the east coast and Puget Sound on the west.
From the Blue Marine Foundation were Tim Glover and Simon Harding who have been leading the Solent Oyster Restoration Project since 2015. Also from the UK were our Solent project partners Dr Joanna Preston and Luke Helmer from the University of Portsmouth, with Dr Alison Debney of the Zoological Society of London representing the Essex Native Oyster Restoration Initiative, on which BLUE is also represented. The rest of the team consisted of Karel van den Wijngaard of ARK Nature from the Netherlands and two staff members from The Nature Conservancy (TNC): Anita Nedosyko, an oyster restoration manager from South Australia and Mike McCann, an urban ecologist based in New York City who is working with the Billion Oyster Project there. All were there thanks to Boze Hancock of The Nature Conservancy’s Global Oceans programme, ecosystem restoration ‘guru’ and expert oyster tour organiser.
We spent the first night in Cambridge, Maryland, near to our destination next day, the Horn Point Laboratory, part of the University of Maryland’s Center for Environmental Science which contains the world’s largest oyster hatchery for Crassostrea virginica, the native oyster on the east coast of the United States. It was a day of two Stephanies – in the morning we met Stephanie Westby, the manager of NOAA’s Chesapeake Bay Programme who gave us an overview of the restoration work across the whole of the bay system. We were then given a guided tour of the Horn Point Laboratory and oyster hatchery by Stephanie Alexander, the overall manager of the facility.
The Chesapeake Bay Programme is based on a strong partnership that involves federal and state government agencies, the US military, academic institutions from both Maryland and Virginia, NGOs and scientists. Oyster restoration in Chesapeake is focused on six tributaries; three in the upper bay in Maryland and three in the lower part in the state of Virginia. Large-scale oyster restoration was triggered by Presidential Executive Order in 2009 and the Chesapeake Bay Agreement signed by the governors of the bay’s watershed states in 2014 with the common goal to restore oyster populations in 10 tributaries by 2025. To achieve this the federal and state governments and, surprisingly, the military, have provided extensive funding. For example the three tributaries in Maryland alone have received $47 million between 2011 and 2016 for oyster reef construction and seeding. This remarkable level of investment has restored 564 acres of oyster reef and seeded these areas with over three billion hatchery-reared spat.
The scale of the restoration efforts in Chesapeake is staggering. When Stephanie Alexander gave us a guided tour of the oyster hatchery, the scale of the operation was at first difficult to take in. The hatchery produced six billion oyster larvae in 2016, of which four billion were used for restoration initiatives. The main technique employed for restoration is to settle the larvae in large tanks onto clean oyster shells, known as ‘spat on shell’. These are then transported by boat to the sites and pushed directly off the deck with a fire hose. The hatchery also sells bags of oyster shell to local fishermen and aquaculture businesses. The hatchery provides the larvae at no cost to the commercial growers or harvesters, they only have to provide the shells for settlement. For spat on shell laid at restoration sites the oyster survival rate to maturity can be up to 30%. This technique enables large numbers of oysters to be re-seeded and eliminates the growing-on costs in a hatchery which are very expensive.
With our minds full of oyster facts and figures we then jumped in the tour bus and made our way down to Virginia to see some of the restored oyster reefs up close. TNC generously let us stay at Brownsville Farm for the next two nights on the Eastern Shore, a 17th century colonial property surrounded by extensive grounds, which unfortunately had a healthy population of large and voracious mosquitoes. After an introduction to the various restoration programmes TNC are doing on Virginia’s Eastern Shore we made the short journey to a small town actually called ‘Oyster’ to meet the boats that would take us out to the reefs and restoration sites within the Virginia Coast Reserve, the longest stretch of coastal wilderness on the east coast of the US.
The day was led by Bo Lusk, the reserve’s marine programme manager, a local with extensive knowledge of the region. First we motored out to a natural Crassostrea oyster reef and got stuck in the mud around the clusters of oysters. The importance of oyster reefs and other habitats such as seagrass beds and salt marshes as a living barrier to protect the coastline from storm surges was clear to see. Next stop was a salt marsh where oyster reefs are built up along the edge of eroding salt marshes using interlocking concrete blocks to create ‘oyster castles’. These encourage natural oyster settlement and the resulting reefs form a barrier to reduce wave action. Seagrass restoration is also an important component of the work in the reserve. Our lunch break was taken over a seagrass bed that also contained native oysters where many of the group took a quick snorkel to explore the habitat over low tide. Later, back on land, Bo showed us the large tanks used to collect seagrass seeds for creating new beds and proudly told us that this was the largest seagrass restoration project in the world.
Back on the bus again and leaving Virginia’s eastern shore early the next morning we travelled across the southern end of Chesapeake Bay on the 23-mile-long bridge-tunnel to visit two more project sites on the western side of the bay. First stop was the award-winning Brock Environmental Center on the Lynnhaven River, the headquarters of the Chesapeake Bay Foundation, said to be one of the most eco-friendly buildings in the country. Here we met Jackie Shannon, CBF’s oyster restoration manager for Virginia who explained that the Foundation works across Chesapeake Bay in both states and outlined the innovative approaches used to help restore oysters. These include shell recycling programmes using volunteers, ‘shell strings’ (wires with oyster shells used to detect pulses in oyster larvae recruitment in the bays’ tributaries) and ‘oyster gardening’, a simpler version of the oyster cage work BLUE is doing in the Solent with its partners, where oysters are kept in small cages by members of the public to help improve biodiversity and water quality. In the afternoon Jackie took us out on the Lafayette River, a tributary running through an urban area where poor water quality led to the closure of the river to oyster harvesting in the 1970s. Surveys of the river bed found 48 acres of oyster reef that had recovered from historic over-harvesting. By increasing oyster reefs through the addition of stone substrata and oyster larvae the site is close to meeting the restoration goal for the Lafayette River as part of the overall Chesapeake programme chaired by NOAA. The increased level of oyster filtration is also thought to have been a major factor in the river now passing water quality standards.
On our last day in Virginia, Andy Lacatell, a conservation specialist with TNC in Virginia took us out on the Piankatank River to see large-scale oyster reef construction in action. Here a barge was laying 25,000 tonnes of granite stone to become the settlement substrate for natural spat settlement and create a new 25-acre reef. The stone was being laid in rows following a new design that aims to maximise the ecological benefits provided by the oyster reef. Spat levels in the Piankatank are naturally high as the local bathymetry and tidal currents help to retain oyster larvae in the tributary. We also were lucky enough to each contribute to oyster restoration in the Piankatank by adding baskets of spat on shell to the edge of an existing reef. While we were doing this we spotted six ospreys that nest along the river, often on purpose-made wooden platforms. It was a great way to spend 8 June, World Oceans Day. Back on shore there was an impromptu discussion with senior restoration management staff, including a colonel from the US Army Corps Engineers, for the Piankatank who were attending a ceremony on the water to celebrate progress of the work.
That night we flew to Seattle to visit restoration projects for the Olympia oyster, Ostrea lurida, which is more similar to the European oyster, Ostrea edulis, than the ones we had seen on the east coast. On our last full day of the study tour we met Jodie Toft, director of marine conservation at TNC in Washington State. The biological similarity between the Olympia and the European oysters, belonging to the same genus, meant that restoration efforts on this coast were the most relevant to projects in Europe and Australia, where another native species occurs, Ostrea angazi, so the team was excited about the prospect of seeing a restoration site for this species. We took a bus on to the downtown ferry, crossed over to Bainbridge Island and headed for Liberty Bay. Again, multiple partners including government agencies, the US Navy, NGOs such as the Puget Sound Restoration Fund and TNC have worked together to restore around 50 acres of oyster beds in Liberty Bay with an overall goal of reaching 100 acres for this location. Heading out to the muddy intertidal beds of the bay we could see that Olympia oysters were recruiting not only on to the introduced substrate of Pacific oyster shells but also on to intertidal rocks and boulders. In some places the oysters were also forming small clusters which is very encouraging for our future work in the Solent. The European oyster may also form clusters given the right conditions and even form natural oyster bed habitat which is extremely rare in Europe.
The last visit was to the oyster hatchery at NOAA’s Manchester Research Station. This new centre for shellfish research and restoration was opened in 2014 and is jointly run by NOAA and the Fund. Hatchery manager, Ryan Crim showed us around the facility and explained that the main focus is to restore the Olympia oyster populations in the Puget Sound using both spat on shell and direct re-seeding of quarter-sized (25 mm) single oysters in the intertidal zone. The hatchery was built following the declaration of shellfish initiatives at both the state and national level in 2011. The facility was not on the scale of Horn Point and the techniques used were specifically designed for the Ostrea species rather than Crassostrea. Many in the team agreed that this type of hatchery was needed in Europe if oyster restoration is really going to take off, as a reliable supply of oyster larvae is critical for success.
With our minds bulging with valuable oyster information we headed back to Seattle. The wealth of knowledge we have gained from this trip will help us to shape oyster restoration efforts in the UK and in Europe. BLUE and the rest of the team send huge thanks to Boze Hancock, TNC and all its partner organisations who helped to make the tour such a success. European oyster restoration here we come!
