IMIS

Marine Scotland Science (MSS) have installed an array of 40 Vemco VR2AR acoustic receivers running between Burghead and Tarbat Ness. It provides coverage across part of the inner Moray Firth to detect tagged Atlantic salmon (Salmo salar) smolts and sea trout (Salmo trutta) smolts as they migrate from the Cromarty Firth. The VR2ARs are on loan from the Ocean Tracking Network (OTN). The Array has been installed to give more information on the migration routes of the smolts tagged in the Conon River system. 150 salmon and 20 sea trout smolts were tagged in late April with 7 mm coded acoustic tags by the Scottish Centre for Ecology and the Natural Environment (SCENE). SCENE have been Commissioned by Beatrice Offshore Windfarm Limited BOWL to carry out this work to discharge Section 36 consent and Marine Licence conditions. The salmon smolts were collected from the River Bran (a tributary of the Conon) at Achanalt. Fish were tagged and then immediately released downstream of the Torr Achilty power station on the lower River Conon to continue their migration. Two types of tags were used, Thelma Biotel (ADT-LP-7,3) in salmon smolts and Vemco (V7) in sea trout smolts. MSS have designed and commissioned pop-up rope canisters to house the VR2ARs to allow the recovery of the weights and avoid acoustic shadows caused by flotation buoys above the hydrophone. These rope canisters were designed to Accommodate up to 150 m of 4 mm Dyneema rope. This allows the safe recovery of the 70 kg clump anchor weights in up to 100 m of water. The installation of the VR2ARs was carried out on the Coral Wind on the 19th April 2016 and all 40 moorings were deployed in one day. MSS have scheduled the receiver recovery for the start of August. We plan to provide initial assessments of patterns in the migration vectors of the fish leaving the Cromarty Firth by late autumn.