During the summer of 2013, Marine Scotland Science (MSS) are planning to deploy pop-up satellite tags on up to 50 salmon on the north coast near Strathy as part of an investigation into the potential for interaction between returning adult salmon and marine renewable energy developments. Satellite tags record information on swimming depth and water temperature and relay these data via satellite to a shore-based receiver station. Satellite tags cannot transmit in sea water, but are programmed to pop off after a pre-programmed delay when they float to the surface to begin to transmit the data they have stored. The system for detachment works only in sea water (the process is corrosive) and tags may stay attached to fish if they enter rivers before the programmed release time.
It is possible that a tag that has failed to detach might be found on a salmon within in a river, particularly in the Northern region. Fish carrying the remains of the tag attachment system (a couple of sutures just posterior to the dorsal fin) might turn up anywhere in Scotland. MSS are particularly keen to retrieve any tags found in rivers, as it is likely that the information they contain will not have been passed on via satellite.
A reward will be paid for any satellite tag returned to MSS (a note to this effect and a phone number appears on the tags). The tag can be removed from a fish simply by cutting the sutures with a knife or scissors, and the fish can then be returned to the river. If there is no satellite tag, but the tag attachment system is still in place, there may also be an identification number attached to the sutures. In this case, we would be very grateful if this number tag could be removed and returned to MSS, together with the date and location at which the fish was caught. Any photos taken of the fish and the attachment system/site would also be most helpful.
Freshwater Fisheries Laboratory
Marine Scotland Science
PITLOCHRY PH16 5LB
Tel: 01224 294461