Bluefin tuna have been tagged with state-of-the-art acoustic tracking tags for the first time in UK waters. The huge fish, which in UK waters can be up to 2.5 m long, are commercially valuable and biologically fascinating. The 7cm long tags send individually coded sound (acoustic) messages to listening stations moored on the seabed, allowing the team to record how long bluefin tuna are in UK waters each year.

The tags will also help the project team understand when the fish arrive, and how quickly they can make the journey across the Channel to France. Dr Lucy Hawkes, Senior lecturer in ecology at the University of Exeter, is leading the bluefin tagging work.

The research will assist authorities across the Channel region to implement Ecosystem Based Fisheries Management (EBFM) programmes with the aim of enhancing the condition and water quality of these habitats, as well as enabling human activities – such as fishing, civil engineering projects and extract industries – to function in a sustainable way.

This work is part of the FISH INTEL project, and the project lead, Dr Emma Sheehan, said: “Important fish like bluefin tuna are sentinels of healthy ecosystems, they travel between waters that provide them with food and clean conditions.”

The team will continue to collect data from the tagged fish until 2026, and will gain the most comprehensive understanding of the importance of UK waters to bluefin tuna to date. More information about bluefin tuna in UK waters is available here.