Tyne marine life rescued before home is to be buried by tunnel spoil
FIVE days of fishing have rescued marine life from a dock which will be filled in with spoil from the building of the new Tyne Tunnel.
The 300ft long, 3,000-tonne cutter suction dredger, Vesalius, was moved into position yesterday off Jarrow to start the six-week job of creating the underwater stretch of the tunnel trench.
Around one million tonnes of material excavated from the New Tyne Crossing site will be used to fill the Victorian Tyne Dock, with approximately 800,000 tonnes of material from dredging and the remaining 200,000 tonnes from land excavations. One of the planning conditions for the infilling of 13 acres at the dock was a survey should be carried out of creatures which may live there.
Specialist fishing contractors found a significant number of eels in the dock at South Shields.
Because eels are a biodiversity action plan species due to their decline across Europe, it was decided to undertake a fishing operation using fyke – or tunnel-like – nets and a small trawl net.
The haul totalled 95 eels, 487 pollack fish, 11 cod, six herring, three plaice, three lobsters, crabs and two long-spined sea scorpions. All were returned to the river.
Environment Agency staff will monitor the river to ensure water quality and fish health – particularly migrating salmon on their way to breed in the upper Tyne catchment – are maintained during the dredging operation.
The Tyne is one of the best salmon rivers in England and studies have shown each rod-caught salmon can generate as much as £4,600 for the local economy.
The dredger will suck sediment and water up and reduce the amount of silt that would be disturbed by the more usual bucket dredger. Silt will then be transferred 1.5 km downriver via an enclosed pipe system, and used to fill the now redundant Tyne Dock, creating 13 acres of development land for the Port of Tyne. Phil Rippon, regional technical fisheries specialist for the Environment Agency, said: “This dredging system will have a significantly lower risk to the environment overall than the method proposed originally. However we still have to ensure that impacts are minimised, especially for the salmon stocks.
“We’ll be monitoring the water quality continuously during the operation at several key points around the dredge site and the Tyne Dock to measure the level of waterborne sediment and dissolved oxygen in the river and help ensure water quality stays above these preset thresholds.
“If the water quality drops below these thresholds then work has to stop until the dredging activity can be modified.”
Once the tunnel sections have been placed in the dredged trench sand taken from the navigation channel in the mouth of the Tyne will be used to cover the trench.