UNDERWATER research at the Tees Barrage has found that seals can be put off from catching salmon with a certain sound.

Since 2008, the Tees Barrage Fish Pass and Operation Steering Group has been overseeing the monitoring of fish and seal populations and their behaviour to try and reduce seal predation.

The research involved the use of underwater sonar monitoring to understand the fish, and an acoustic deterrent device (ADD) to deter seals from entering the navigation lock.

During the use of ADD in a 30-day monitoring period, four fish were eaten. This compares to 18 fish eaten in a 21-day period before ADD was installed.

In the 17 days after the ADD was removed just one fish was eaten.