New advanced robotic technology is helping marine scientists in tracking salmon juveniles across the open ocean
The ability to track free swimming salmon juveniles has been extended hundreds of kilometres into the open ocean using advanced robotic technology.
As part of the EU INTERREG VA-funded SeaMonitor project, Dr Ross O’Neill, Marine Institute and Kieran Adlum, P&O Maritime, tested a remotely operated “ocean glider”, equipped with an acoustic tag detector along the steeply sloping area of the shelf edge approximately 130km north-west of the Scottish Hebrides. The ocean glider was deployed from the RV Celtic Explorer on 16th April during the 2021 Irish Anglerfish and Megrim Survey. During its two-month mission, the glider successfully detected four individual juvenile salmon smolts measuring only 15 to 19cm, nearly 600 km from their home rivers in Ireland, Northern Ireland and Scotland.
These fish had been tagged between four and six weeks previously with electronic acoustic transmitting tags along with hundreds of other juvenile salmon as part of the SeaMonitor project but also as part of the West Coast Tracking Project, a partnership between the Atlantic Salmon Trust, Fisheries Management Scotland and Marine Scotland, EU INTERREG VA-funded COMPASS project and Agri-Food Biosciences Institute (AFBI) research initiatives. One of the main aims of these projects is to investigate the persistent low marine survival of Atlantic salmon in the early stages of their oceanic migration to feeding grounds in the North Atlantic.
The four fish originated from the River Burrishoole in Co Mayo Ireland, the River Bann in Northern Ireland and the Rivers Clyde and Awe in Scotland.
Up to now, most tracking studies had been limited to estuarine or coastal areas due to technology limitations and the need for stationary receivers.
According to Dr Niall Ó Maoiléidigh of the Marine Institute and Principal Investigator for the SeaMonitor Project, “The detection of these fish confirms the importance of the shelf edge in this amazing journey, as the faster currents associated with the steep slopes most likely act as an aquatic transport system facilitating the northward migration of these tiny fish through a very harsh environment.”
Prof Colin Adams University of Glasgow and Principal Investigator for the SeaMonitor Project said, “This study shows that tracking salmon over considerable distances at sea can be achieved which is crucial for research into highly migratory marine species especially where mortality may be occurring far from the shore.”
Dr Ciaran Kelly, Director of Fisheries Ecosystems and Advisory Services at the Marine Institute said, “The use of the glider to track the movements of even very small fish has been clearly demonstrated and this will encourage the use of autonomous underwater vehicles to improve information on many marine species of animals which may be endangered or threatened without interfering with their natural migrations.”
Sharon McMahon, Loughs Agency CEO said, “with funding from the EU’s INTERREG VA Programme, the SeaMonitor project led by Loughs Agency, is breaking the boundaries of research into the marine migration journey of the iconic Atlantic Salmon. This innovative research will help to identify migratory routes and factors influencing salmon survival at sea, providing data to inform future research and decision making”.
Underlining the importance of the project Gina McIntyre, Chief Executive of the Special EU Programmes Body said: “Our shared marine environment is under threat with many species, such as Atlantic Salmon being endangered. The research that is funded by the INTERREG VA Programme, is being undertaken by the SeaMonitor project, and will provide invaluable data that can be used to gain a better understanding of the migratory patterns of Atlantic Salmon and what is potentially disrupting them. This research will inform future environmental protection efforts, on both sides of the border, and is a testament to the partnership-based approach which underpins the INTERREG VA Programme.”
This result represents a huge input by many participating institutions and organisations in organising and tagging salmon juveniles (smolts) as they leave their natal rivers to migrate to oceanic feeding grounds to deployment and successful piloting of the ocean glider.
The active tracking technology allowing the detection of marine species is constantly evolving and while techniques have also been used in Canada and the USA, this is the first time it has been applied to Atlantic salmon in Europe. The glider is part of the SeaMonitor integrated cross-jurisdiction major network of acoustic receivers, robotic underwater vehicles, satellite tracking and passive acoustic receivers in European waters and its use will be extended to track cetaceans, basking shark and skates as well as to collect physical oceanographic data. When combined, the data will enable a holistic view of the regions mobile marine species and will prove invaluable to the regions managers, as well as establishing an integrated network of marine receivers for future applications and extended monitoring.
Match-funding for the project has been provided by the Dept. of Agriculture, Environment & Rural Affairs in Northern Ireland and the Department of Housing, Local Government and Heritage in Ireland.
For more information about the project visit: www.loughs-agency.org/seamonitor or follow the project on Twitter (@SeaMonitor1). SeaMonitor is a project supported by the European Union’s INTERREG VA Programme, managed by the Special EU Programmes Body (SEUPB).