The Environment Agency, which  linked a chemical spill of pesticides at Orton Southgate industrial estate with the death of an estimated 4,000 fish in the river, says the slug of dead fish has passed through to Wisbech.

Norman Robinson from the Agency said:

“We are no longer seeing fish struggling in the water and believe the worst to have passed but we are staying alert and continuing to monitor throughout the week and weekend.”

Tens of thousands of fish, mostly roach, were seen in distress along the length of river from Orton Mere to Wisbech after the 5,000 litre chemical spill at the weekend. Now the Agency is waiting for results of water tests to confirm the danger has passed before giving the all clear to water users.

Throughout the week the Agency has been managing water flows between Orton Mere and the Dog in a Doublet Sluice to help dilute the chemical pollution which lowered the risk to wildlife.

“We have been unable to save some fish and our biological surveys have shown there is likely to be a long-term impact on the flora and fauna of the river. The exact effect is not yet known,” said Mr. Robinson.

He praised the support of anglers by not fishing along the affected stretch of the Nene to give remaining fish a chance to recover from the stress of the pollution.A penstock close to Orton Southgate remains closed to prevent any further chemicals escaping to the river and the spill is being cleaned up.

The agency has also been in talks with organisations around the Wash to ensure the very small risk to waters beyond Wisbech is understood and managed.