Stocking up

Categories: Features, News and previews

Richard Haward of the eponymous Borough oyster stand on the Thames Estuary Oyster Mother Sanctuary: a collaborative initiative that seeks to increase vulnerable native oyster stocks

Words: Clare Finney

“There is an old saying among oystermen that when oysters spawn and become spats, the first thing they think of is dying,” says Richard Haward dryly. An oysterman all his life, like his father before him, there is nothing about Colchester native (or European flat) oysters Richard doesn’t know. “If the weather is too hot, if the weather is too cold, if there is nowhere suitable to settle, if they are eaten by predators, that’s it for spats,” he continues. Then there’s the problem with historical overfishing, with stock depletion being recorded even in the first century. Factor in 20th and 21st century concerns—habitat loss, pollution and the introduction of diseases—and you can see why native oyster stocks, not just in the Thames Estuary but across northern Europe, have plummeted. In the UK, native oyster populations have declined by more than 95 per cent.

“It was about 10 years ago that the oystermen of Mersea realised some action would have to be taken if the population of native oysters was going to recover,” Richard remembers. “At around the same time, the government had just started designating areas as marine conservation zones, which sounded like the avenue we wanted to go down.” In 2013 the Blackwater, Crouch, Roach and Colne Estuaries were designated a Marine Conservation Zone (MCZ) by the UK government, with the conservation objective of recovering both native oyster beds—the habitat—and the population. Spanning 284km2, it is the largest restoration project in Europe.

“Since then, all manner of organisations—local communities, NGOs, Essex University and the government—have got involved, working together. I help with experience and ideas and general decision making, attending meetings in London every quarter or so.” Gradually the project for restoring and reviving our native oyster populations took shape, and the Essex Native Oyster Restoration Initiative (ENORI) project—a coalition of these organisations, chaired by the Zoological Society of London—came together.

Sustainable growth
An area in Blackwater which historically teemed with oysters was set aside as a restoration area. “Spats need something to settle on, there’s no use producing them otherwise,” says Richard, “so we laid cultch [a mix of old shell and gravels] to the seabed in order for them to settle and develop.” Keeping the area clear of silt (not to mention pollution and plastic) is essential. Some of these shells are cockle shells from the Thames cockle fleet; others hail from here in Borough Market: “We send our old oyster shells from the stall there. They are one of their favourite shells to settle on.” He has to be careful; “we only want native oyster shells, not oysters taken from anywhere else, as we need to avoid diseases.” In time they hope to add recycled scallop and possibly even mussel shells to the cultch, as a further move toward sustainable growth.

It’s on this improved seabed of cultch that ENORI will eventually establish the endearingly dubbed Oyster Mother Sanctuary, translocating mature oysters from elsewhere to spawn and settle on the improved substrate. Adult females or ‘mother oysters’ are laid which, when conditions are right, will spawn in the following weeks, initiating the first stages of the native oyster’s life cycle. Relocating oysters is nothing new, of course: it’s what the Haward family have been doing for generations, taking young oysters from the River Blackwater and laying them in their oyster beds, where they are enriched by incoming tides which bring nutrients from the marshlands. “The river produces a lot of young oysters, but it doesn’t necessarily produce the right oysters for consumption, so they need relaying to creeks here in Mersea,” says Richard.

While oysters have been around for millennia—oyster farming has been recorded in Mersea since the Roman times—it’s the trials and tribulations of the last 150 years that led oystermen and conservationists to conclude this seriously depleted population cannot recover alone. When alive, Richard’s father recalled to him the harsh winters of 1947 and 1963 which caused particularly high mortalities on the east coast. “Stocks had only just recovered from that when an oyster disease picked up from Cornwall destroyed them again,” he tells me. Then, in the early 1980s, TBT (tributyltin) anti-fouling paints used on ships and boats affected reproductive capacity and caused stunted growth.

A long process
The recovery of native oysters is not just important from a culinary point of view, or even from the perspective of waterside economies. Oyster beds used to be an important structural and ecological component of Britain’s bays and estuaries, providing the foundation for entire ecosystems by filtering water and providing food and habitat for wildlife. One adult oyster can filter more than 10 litres of water in a single day.

I ask Richard how long he thinks it will take for the Thames sanctuary to be established sufficiently before any can be harvested. “Oysters need to grow to three years old until they even spawn, and a lot can happen in that time.” Can he give a rough estimate? “How long’s a piece of string? Not in my lifetime, that’s for sure,” he laughs with equanimity. “But with hard work, I think we’ll get there. It’ll be a long process to build stock up, but we’ll get there. Slowly.”