Summary
An acoustic deterrent device (ADD) was tested at a Scottish salmon double bagnet to deter seals (grey (Halichoerus grypus) and harbor (Phoca vitulina)). The ADD was randomly assigned to be on or off during observations, which were carried out from shore. When the ADD was on, there were significantly fewer seals observed and 1/3 more fish were landed per hour than when the ADD was off. Seal damaged fish were only found when the ADD was off.