Atlantic Bluefin Tuna Research Programme - Satellite Tagging
The Marine Institute continues to play a leading role in improving understanding of Atlantic bluefin tuna (ABFT) ecology and migration in Irish waters through satellite tagging studies conducted both independently and in collaboration with the International Commission for the Conservation of Atlantic Tunas (ICCAT). These efforts are part of the ICCAT Atlantic-wide Research Programme for Bluefin Tuna (GBYP), which aims to refine knowledge of stock mixing, spatial ecology, and migratory behaviour to support effective conservation and management of this iconic species.
Overview
Since 2016, the Marine Institute has deployed a total of 147 satellite tags on Atlantic bluefin tuna in Irish waters, helping to map their movements across the Atlantic Ocean and into the Mediterranean. These include:
• 79 tags deployed under the ICCAT GBYP programme via MoU agreements
• 68 tags deployed independently by the Marine Institute through its national research programme
Tagging has primarily taken place in Donegal Bay, an area now recognised as an important seasonal foraging ground for bluefin tuna. Additional tagging has also been conducted off the south coast of Ireland, particularly around Courtmacsherry and surrounding bays, expanding the spatial scope of the research. The combined dataset contributes to an improved understanding of tuna stock mixing, migratory corridors, and environmental drivers of tuna behaviour. The programme also supports Ireland’s contribution to international stock assessment and management strategy evaluations (MSE) for this highly migratory species.
Tagging Methodology
Fish are caught using recreational-style rod and line with squid spreader bar lures. Once hooked, tuna are brought aboard through a transom door via an adapted ramp and tagged within a couple of minutes using best-practice welfare protocols, including continuous gill irrigation and sedation via eye covering. Satellite tags are implanted in the dorsal musculature using biocompatible titanium darts, and tissue samples are taken for genetic analysis.
All tagging data contribute to improving our understanding of habitat preferences, vertical behaviour, and long-range migrations of ABFT across the Atlantic and into the Mediterranean.
Research Impact
Recent analysis of Marine Institute tagging data, including a 2024 study by McNicholas et al., highlights a consistent seasonal return of bluefin tuna to Irish waters and confirms migrations toward the Bay of Biscay, central Atlantic, and even Iceland. Environmental drivers such as sea surface temperature, bathymetry, and oceanic eddies are shaping these movements. These findings support the hypothesis of historic high-latitude foraging ground reoccupation and underscore the importance of Ireland in the broader Atlantic bluefin tuna life cycle.
Tag Recovery Reward
If you recover a tag from a bluefin tuna, a reward of €100 is offered. Each tag is marked with a unique identifier. If you find a tag, please contact Hugo Maxwell at the Marine Institute:
Phone: 091 387200
Email: hugo.maxwell@marine.ie
Returning recovered tags is vital to unlocking the full scientific value of this work.
Published Research and Scientific Impact
Data collected through this tagging programme have contributed directly to peer-reviewed scientific publications.
Key publications based on Irish tagging data include:
• McNicholas et al. (2024) – Seasonal variability of high-latitude foraging grounds for Atlantic bluefin tuna (Thunnus thynnus)
This study highlights recurring seasonal use of Irish coastal waters and expanding habitat utilisation linked to ocean warming.
Read the paper on ResearchGate
• Pagniello et al. (2023) – Tagging of Atlantic bluefin tuna off Ireland reveals use of distinct oceanographic hotspots
This paper outlines the discovery of consistent migratory corridors and foraging areas for bluefin tuna around Ireland, based on satellite telemetry.
Read the paper on ResearchGate
Partners and Support
This work is funded by the Marine Institute and ICCAT GBYP with support from the European Union and ICCAT Contracting Parties. The Marine Institute continues to work in collaboration with international and national partners including Stanford University and Trinity College Dublin.
