The now scarce European Native Oysters used to be a major feature in the UK. Large stretches of inshore waters, including our own Tees estuary, were once covered in vast areas of oyster reefs. For hundreds of years these small bivalves sustained the livelihood of coastal communities. As far back as Roman times, there are reports of barrels of oysters being shipped from Colchester to Rome where they were highly prized. In more recent history, In 19th century London 700 million oysters were consumed in a single year. Due to the industries they supported, the Native Oyster also held cultural importance with ‘Oyster Day’ celebrations being held to mark the first Oyster catch of the season.
Where did they go?
Due to their popularity the Native Oyster was heavily fished leading to large areas of reef being rapidly depleted. This combined with decreasing water quality caused by the industrial revolution spelt disaster for Native Oyster populations. Even when fishing pressures were stopped, populations were too low for the oyster reefs to make a recovery and they became extinct in large areas of their range. In an attempt to replace depleting oyster stocks, pacific oysters were introduced to UK coastal waters. These, alongside other invasive species, put further pressure on the few remaining Native Oyster populations. All these factors have led to a 95% decline in Native Oyster populations since the 19th Century.
Why are they important?
Native Oysters have been labelled as a ‘species of conservation importance’ in environmental legislation; and for good reason. When left alone Oysters will create complex reef structures which provide a habitat for a wide range of plant, invertebrate and fish species. Being filter feeders, they also play a large role in increasing water quality. A single oyster can filter 200 litres of water a day, removing pollutants from the water and increasing water clarity. There is also evidence that oyster reefs can reduce wave action protecting coastal communities from flooding.
Due to the great benefits they can bring, we have hired a new team with the aim of reintroducing these coastal heroes, among other species (more on that in a future blog!), to the Tees estuary.
If you want to find out more about the #FishforTees project and the work we are currently doing get in touch with judy@teesriverstrust.org