Oysters re-introduced into river to clean water
BBC/Louise HobsonA small scale oyster nursery is being placed into the River Tees as the next step in a long-term conservation project.
The Tees Rivers Trust said it would monitor the oysters monthly and compare the data with other regional nurseries before installing a reef at the south of the Tees estuary, near Bran Sands.
Last year, about 20 oyster reef cubes containing 4,000 European native oysters were released off the north-east coast.
Project manager Judy Power said oysters were "eco-system engineers" and if the oysters can form reefs they boost other species like mussels and crabs.
"The statistics are that one native oyster can filter 200 litres of water every day," she said.
"Back in the early 1900s, the south bank of the Tees was prolific with native oysters and people used to come to collect them for their tea - we have lost a lot of that population."
BBC/Louise HobsonAlongside the oyster restoration project, the rivers trust is also working on boosting mussels and seagrass.
"If we restore one species then the others will benefit, they all slot together and support each other," Power said.
The team will know if the oysters in the River Tees are doing well based on growth rates, mortality rates and biodiversity in their containers.
"If it is the same as our other nurseries we will know that is good and we are clear to start looking at putting a reef in," Power added.
Oyster nurseries have previously been installed in Sunderland and reef deployments have taken place off the coast at Whitburn in South Tyneside.
The team will know if the oysters in the River Tees are doing well based on growth rates, mortality rates and biodiversity in their containers.
"If it is the same as our other nurseries we will know that is good and we are clear to start looking at putting a reef in," Power added.
Oyster nurseries have previously been installed in Sunderland and reef deployments have taken place off the coast at Whitburn in South Tyneside.