The Atlantic Salmon Trust (AST) was founded in 1967 in response to growing concerns about overexploitation of wild salmon coastal waters. Since then the AST has become one of the UK’s foremost advocates for salmon conservation.

In spring 2018 the Missing Salmon Project was born after an alarming statistic regarding wild salmon numbers: for every 100 salmon that leave UK rivers for the sea, less than 5 return. This is a decline of nearly 70% in just 25 years. The Missing Salmon Project hopes to uncover the salmon migration route to help prevent further decline of this iconic species, by tracking their progress with acoustic fish tags.

In early 2019 RS Aqua supplied over 800 Vemco fish tags and over 200 Vemco listening receivers to the AST for the first year of the project, where the focus of work was the Moray Firth and 7 of its tributary rivers. The Moray Firth system is the route taken by 20% of all salmon that leave the UK.

Having recovered the 2019 receivers the team at the Missing Salmon Project have been working tirelessly to analyse over 15 million tag detection data points. One of the early findings is that 50% of the tagged salmon smolts went missing in freshwater riverine sections of their migration route, and 15% in inshore waters. For the second year of the project, RS Aqua supplied a further 1580 tags and 170 receivers. The Missing Salmon Project plan to use this new equipment to expand their receiver arrays to collect more evidence on where salmon smolts are going missing.

RS Aqua are sponsors and technical partners of the Missing Salmon Project, providing expert acoustic telemetry technical support to the research team. RS Aqua’s ARC Acoustic Release Canister is a key part of the Missing Salmon Project’s acoustic telemetry receiver arrays and allows the researchers to safely recover all of their seabed infrastructure when recovering their equipment. The photo above shows some of the AST’s ARC and BARC (Big Acoustic Release Canisters) units ready for deployment in the coming days.