Dear WSC Sailors, boaters and kayakers
Writing this as we have 40 knots of wind blowing in Wembury bay we are looking out of the window looking forward to the next sailing, kayaking and fishing season. We are also planning the boat refit and multiple jobs to do before we get afloat again.
A good friend has just sent an email to say that he and his wife have made it sailing from the Canaries to Grenada in the Caribbean. They have experienced particularly strong trade winds this year and made quite a fast passage. Covid permitting, they are planning on sailing through the Panama Canal with the aim of reaching Australia where they hope to meet their grandson for the first time since the beginning of the pandemic. Unfortunately following the rather challenging voyage, his wife stepped ashore, falling on the pontoon and broke her wrist. The picture that they sent was of her holding a Pina Colada in one hand with her wrist in plaster on the other!
A newspaper article caught my eye on New Year’s day regarding Pacific Oysters and the River Yealm highlighting how the Oysters have razor sharp shells and have caused quite a number of serious cut injuries.
The report stated that ‘Mrs Christine Wood’ slipped and slashed open her arm on the razor-sharp shell of a Pacific oyster while walking along the banks on the River Yealm.
It was the second time she had been badly injured by the invasive species, which is undergoing a population explosion that threatens to encrust estuaries and harbours in harmful feet-deep reefs. The oysters, reach maturity in a couple of years, can each produce up to 200 million larvae a year. Unless their spread is halted they will significantly alter protected coastal habitats and change the appearance of some of our most popular holiday destinations. Christine Wood’s first injury was when she sliced the palm of her hand open while turning over a boulder. She now wears gloves and there are warning signs along the estuary.
“The increasing presence of Pacific oysters on the shore has definitely made surveying more difficult and dangerous,” she said. The harbourmaster has seen numerous people cutting their feet after jumping from boats, dogs with injured paws, inflatable paddleboards popped, and the hulls of boats damaged by the oyster shells.
The paper article reported a comment from Matt Slater, a marine conservation officer at the Cornwally Wildlife Trust. “The numbers we are seeing now are pretty terrifying. About five years ago there were virtually none in the areas we surveyed and now we’re finding thousands of oysters. There are oysters growing on oysters, forming large reefs. If they’re not kept under control we could end up finding deep beds of oysters, metres thick, encrusting harbour sides, slipways and also encroaching on important protected estuarine habitats.”
For the past two years a volunteer team has been tackling the oyster invasion along the south coast of Cornwall and Devon. The 16 volunteer groups organised by Natural England and local wildlife trusts have killed more than 170,000 Pacific oysters but the non-native species continues to colonise every estuary from St Ives Bay and Newlyn in west Cornwall to the Salcombe and Kingsbridge estuaries in south Devon. The largest numbers were culled in the Fal estuary (85,044), followed by the Fowey estuary (35,835) and the Helford estuary (29,095).
Pacific oysters were brought to the UK from the United States and Canada and farmed during the 1960s and 1970s. They are larger than our native oyster and prefer the inter-tidal zone, which exposes them to the public at low tides.
They grow best in sheltered estuaries and bays on the south coast of Cornwall and Devon but have begun to colonise the rocky shoreline of less sheltered bays like Whitsand Bay and Mounts Bay, and even Carbis Bay on the north coast of Cornwall. Reefs, formed by oysters growing on oysters, can smother mud flats and soft, muddy shores, taking away vital feeding grounds for protected fish and wading birds.
A government report said there was an average population decline of 89 per cent at sites culled by volunteers but warned further action was needed as they were “super-abundant” in some locations and forming reefs along the shore.
The report said most volunteers considered “control necessary to protect native communities and habitats” but the sight of groups using hammers to “smash organisms on the shore can initially appear quite shocking”.
Hotspots have been identified at several locations, with densities of more than 300 oysters per metre squared in parts of the Fal estuary, Fowey estuary, Plymouth Sound and Yealm estuary. Oyster reefs are forming in all these areas, as well as in the Helford estuary and Salcombe estuary, the report said. Friends have reported seeing a huge amount of them living on a breakwater by Torquay harbour.
When the oysters were brought to the UK, scientists believed the waters were too inhospitable for the oysters to breed in significant numbers. Slater said the warmer waters caused by climate change have created an optimum breeding environment for them in the past decade.
Despite the relative success of the cull, Slater said using volunteers wasn’t sustainable in the long run.
“The only way we will get them under control is if their value is realised and they can be harvested for food or other uses,” he said. “My personal feeling is volunteering isn’t sustainable as it takes a lot of hard work, cost and co-ordination, but if you can create an industry using the oysters it’s a more viable long-term solution.”
For oysters to be fit for human consumption they must be caught in a designated shellfish fishery and then depurated to remove the toxins they ingest.
There are trials using oyster shells in the construction industry for cement, replacement of limestone in neoprene manufacturing and as a garden fertiliser.
“There needs to be a market for them,” Slater said. “It will be prohibitively expensive to control them in any other way.”
The WSC are looking for nominations for the 2022 donations preferring to award to charities or organisations with a local connection and conducting activities on the water in the local area. The decision for any donations is made in November. If you have a charity, organisation or individual that you would like to nominate please email firstname.lastname@example.org.
On Sunday 6th March 2022, we plan to hold our AGM – COVID permitting. Please join us especially if you want a space in the boat park next year. Details will be emailed to members. On Sunday 20th March – All hands to the pumps for the Boat Park clean-up please for the season and on Friday 1st April – The boat park opens again.
Stay safe on the water. Andy Brown Editor – WSC FH Wembury Review