We are testing a new beta website for gov.scot go to new site

wrapper

Scottish Marine and Freshwater Science Vol 6 No 16: Genetic Assignment of Marine-Caught Adult Salmon at Armadale to Region of Origin

Scottish Marine and Freshwater Science Vol 6 No 16: Genetic Assignment of Marine-Caught Adult Salmon at Armadale to Region of Origin

Tuesday, December 22, 2015

ISBN: 9781785449222

Report describing genetic assignment techniques used in order to investigate the origins of salmon satellite-tagged at Armadale on the north coast of Scotland.

Executive Summary

he Scottish Government aims to generate 100% of its electricity from renewable resources, including tidal and wave power, by 2020. These devices have the potential to influence the migratory behaviour and survival of salmon. Little is known about migratory behaviour of returning adults and a better understanding of the migratory routes of fish in the Scottish coastal area will be of benefit in the ongoing development of this new industry. Historical tagging studies have shown that there was considerable scatter in the recaptures of salmon tagged in various locations around Scotland, with fish being found far from their natal rivers. More recently, satellite tags have enabled at-sea locations of salmon on their return migrations to be collected in Scottish waters. However, a thorough understanding of the tagging information was constrained by a lack of knowledge of where the salmon were headed before their tags detached. Here, genetic assignment techniques are used in order to investigate the origins of salmon satellite-tagged at Armadale on the north coast of Scotland. Of all the tagged fish with a location error of less than 25 km, 53 out of 75 (70%) fish could be assigned accurately to river or region of origin. A single fish was found to be of Norwegian origin and, within Scotland, the majority of fish assigned to the North/West (46%) and East Coast (44%) assignment regions. The marine distribution of tagged fish assigned to different parts of Scotland showed no obvious pattern. As such, results of this analysis confirm those seen with conventional tagging investigations and show that homing fish show considerable spatial mixing around the Scottish coast before finally returning to their natal rivers. It is thus also clear that the deployment of renewable energy devices may not only affect local salmon populations, but also more distant ones.