Concern over seal threat to fish

The Tees Barrage was designed to maintain a constant water level

Almost half of the fish passing under a Teesside bridge are being eaten by seals, a pilot study has found.

The fish pass at the Tees Barrage near Stockton was built 12 years ago.

But a study commissioned by the Environment Agency and British Waterways found 49% of salmon and sea trout were not getting through safely.

The 21-day survey was carried out by tagging the progress of 18 fish. A more detailed study will now be carried out to see if the pass can be improved.

Richard Jenkins, ecological appraisal team leader for the Environment Agency, said: "This is a huge number of fish to be lost.

"But we must take into account that these results are a snapshot and may not represent the full picture.

'More alarming'

"What the findings show is the need for a more detailed study, to include an assessment of seal predation so we can make any decisions about the fish pass on the basis of sound, representative information."

The Tees Barrage was designed to maintain a constant water level as well as providing a crossing for vehicles.

Large quantities of natural debris, such as branches, are caught in the barrage when they are washed down the river.

Alan Slater, river manager for British Waterways, said: "The conditions at the time of the study were favourable for the fish to pass the barrage, so this makes the results even more alarming."