For 100 years the native oyster has been absent in the Firth of Forth due to over-fishing. A half century ago they were officially declared extinct in the area. But on Monday, they were back, as a batch of native oysters were thrown from the edge of a boat in the Firth.

These were the first of 30,000 oysters that are set to be introduced to the estuary, in a project carried out by Restoration Forth, a project delivered by multiple organisations including Heriot-Watt University and the Marine Conservation Society.

They had been transported from a native oyster producer on Little Loch Broom and treated onsite to adhere to stringent biosecurity protocols before deployment.

The physical act of reintroduction was not, as Marine Conservation Society's shellfish engagement officer, Caitlin Godfrey, described, complicated ."We took the boat out,” she said, “our oysters in coolers, and then we simply grabbed a handful, dropping them over the side of the boat.”

However, the two licensed sites were chosen only after careful scientific assessment. Ms Godfrey said: “They have been surveyed by the Heriot-Watt divers carried out our site surveys and they have been looking at the condition of the seabed and the species that are already living there to get a good idea of where would be good to restore."

Shockingly, those 30,000 oysters represent just a tiny fraction of the 30 million oysters that it has been estimated were hauled from those waters, yearly, during the 18th century.

“In the 1700s and 1800s,” Ms Godfrey said, “there was a huge oyster bed outside Edinburgh, probably one of the most famous in the UK, and at its peak it was producing 30 million oysters per year. It was a hugely important industry and these oysters were being sold across Edinburgh, Glasgow, down to London

“By the end of the 1800s, it was completely fished-out. The bed was overexploited. So oysters were declared locally extinct – which is why this week’s deployment was just so exciting. We’re finally them back to where they belong.”

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The success in getting the project this far was, she said, partly down to volunteers.

Among them was Bill Simpson, who skippered the boat for the reintroduction. He said: “I’ve been working on the Forth for over 50 years and have read and heard stories of oysters and Newhaven fishermen. It’s good to know we will have oysters back – let’s hope they go forth and multiply.”

However, there will be little chance of eating a native oyster from the Firth in the near future, nor are there any plans to fish them – the purpose of the project being chiefly environmental.

The Herald: Emmy Cooper-Young Heriot Watt Uni with native oyster. Image:t Maverick

“We’re restoring our oysters,” said Ms Godfrey, “because of the environmental benefit they can bring for species and for people along the coastline – but we don’t have plans to establish an oyster industry or fish them out anytime soon.”

Oysters are also not the only species that Restoration Forth is bringing back to the estuary. “We’re working on seagrass as well,” said Ms Godfrey. “There are already areas of seagrass around the Firth of Forth and we’re working on bulking up those areas and working with local communities to help .”

Earlier this year the first seeding of seagrass was successfully carried out in three locations along the Firth of Forth coast as part of the Restoration Forth project.

These two species, native oysters, and seagrass are, Ms Godfrey said, “both really good for improving biodiversity”.

“They’re habitats for lots of other marine species – in particular an oyster reef has got fantastic places for lots of small species to hide, to find food and shelter etc. They’re really good for biodiversity."

“Oysters are also filter feeders so they can help improve water clarity. We’re  interested in seeing if we can help improve the quality and the clarity of the Firth of Forth as well, as it’s quite a mucky environment.”

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Numerous partners, as well as countless volunteeers, have been involved in delivering the project, amongst them the WWF, Edinburgh Shoreline, Fife Coast & Countryside Trust, Heriot Watt University, Marine Conservation Society, Project Seagrass, Royal Botanic Garden Edinburgh, Scottish Seabird Centre, The Ecology Centre and The Heart of Newhaven Community.

The reintroduction has also been supported by the Scottish Government’s Nature Restoration Fund.

Màiri McAllan, Cabinet Secretary for Transport, Net Zero, and Just Transition said: “I’m honoured and delighted to have been part of Restoration Forth’s historic event, returning native oysters to the Firth of Forth for the first time in around 100 years.

"Communities in Scotland are, as they should be, at the forefront of our nature restoration efforts, and it has been very encouraging to see the drive and enthusiasm of people involved in this project to take action to restore and protect their local marine environment."