Irish anglers are to participate in a ‘science-based’ catch, tag and release fishery for bluefin tuna this year, complimenting the work by the Marine Institute of a satellite tagging programme.

This international management plan for the east Atlantic was adopted at the 2018  AGM of International Commission for the Conservation of Atlantic Tunas.

A pilot project organised by the Department of Agriculture, Food and the Marine, the Sea Fisheries Protection Authority and the Marine Institute will involve a maximum of 15 angling vessels primarily from west and north west communities with trained tagging operators.

“This aim of the project is to build on work undertaken to date and to increase our knowledge of the behaviour and abundance of BFT in the waters off the Irish coast,” remarked Minister Michael Creed.

Previous to this arrangement, Ireland had no quota under ICCAT rules and was not permitted to target angling for bluefin tuna. There is a very small bycatch quota available to Ireland and other non quota holding Member States.

Fishermen however are noticing increasing numbers of bluefin tuna from August to November in Ireland’s 200 mile zone and particularly in Donegal Bay.

“They could particularly choke various commercial species, so establishing their presence scientifically is critical,” remarked Francis O’Donnell, CEO of the Irish Producers Organisation.

“This project is a very important development and one that should be welcomed. Knowing how long they stay to feed here and where they go after they leave the Irish coast is of immense importance.”

This project could not have happened without initial scientific working by early pioneers BIM and more recently by Niall O Maoileidigh and his team at the  Marine Institute, he added.

Profile

Bluefin tuna is the largest tuna, and one of the largest fish of all. It is a pelagic, fish-eating species, found from the surface to depths of up to 1,000m and in temperatures from 3o  and 30o Celsius.

BFT is distributed in the pelagic waters of the North Atlantic and adjacent seas from Brazil to Newfoundland in the west Atlantic and from the Canary Islands to North Norway in the east Atlantic.

After spawning in the Gulf of Mexico and the Mediterranean Sea in spring, many BFT migrate into the Atlantic Ocean for feeding, heading along the continental slope and into the open sea. The main routes in the east Atlantic are along the Iberian peninsula into the Bay of Biscay and further north along the west of Ireland and as far north as Norway.

BFT are assessed by the International Commission for the Conservation of Atlantic Tunas (ICCAT).  In 2006 BFT stocks were at a very low level.  ICCAT adopted a rebuilding plan that introduced various conservation measures include TAC reductions, time/area closures, and minimum closures.

In 2008, the TAC was further reduced, stricter control and enforcement in the Mediterranean, particularly in relation to capture of juveniles for cage farming.

BFT is fast growing and recruits to the fishery by age one, with maximum age of at least 20 years. Maturation occurs at four years, corresponding to fork length of approximately 115 cm.  BFT attains a maximum size is 400 cm.

Juveniles migrate north to SW Ireland in summer, to feed in surface waters.

Results of recent international tagging programmes indicate that movement across the currently assumed east-west boundary in the Atlantic does occur. ICCAT now recognise the need to develop quantitative knowledge of BFT mixing rates and integrate this knowledge into the assessment and advisory process

In the early 2000s, BFT became more visible in the waters around Ireland. Sightings subsequently abated as the stock declined in the Atlantic.  In 2014 they began to reappear in large numbers as the stock recovered.

In 2018, reports emerged of large numbers of BFT in the waters around Ireland. There are no scientific population estimates, but much anecdotal information on increased sightings and interactions with commercial fisheries.  Similar reports of increased BFT numbers are coming from UK, Norwegian and Danish waters for 2016 to 2018.

Ireland commenced a new BFT tagging programme in 2016 when nine BFT were tagged.  This programme continued in 2017 with North American partners (Stanford University US and Acadia University NS, Canada) and a new collaborator in Queens University, Belfast. Nine fish tagged with PSAT tags and three with accelerometer tags.

This BFT tagging work, in conjunction with ICCAT, continued in 2018 when 24 fish were tagged with satellite tags and four with accelerometer tags.

The results from the Irish programme (2016 to 2018) are currently being analysed by MI and partners.  Initial indications show BFT tagged off Donegal in October could migrate into the mid Atlantic, Bay of Biscay and Mediterranean and return to the waters off Donegal Bay.

Ireland does not have a quota for Blue fin tuna and accordingly may not have a commercial fishery for bluefin tuna.