There are few predators in the sea as formidable as the Atlantic bluefin tuna. Up to 725kg of torpedo-shaped, metallic-sheened muscle, it reaches a top speed in the water of 70km/h and so is among the fastest animals in the sea.
Uniquely among fish, it is warm-blooded and possesses a biology that allows the rapid transfer of oxygen through its blood stream as it barrels towards shoals of unsuspecting prey. The bluefin tuna is a marvel of nature, the largest of the 15 tuna species and a commanding presence in the open ocean.
The thick layers of muscle that propel the fish through the water also make it highly prized in dining circles and make it one of the most commercially sought after of any animal.
Demand continues to be led by Japan where the first auction of the year at Tokyo’s Toyosu fish market is closely watched. Last January a 250kg bluefin tuna was sold for a record €2.75 million and although fish are not generally sold at that price (the publicity adding value to the first specimen), a single animal can fetch tens of thousands of euro, depending on the weight.
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High demand for a fish that migrates huge distances through open water, frequently in the “high seas” (areas beyond 200 nautical miles of the shore and so beyond the jurisdiction of any one country) led to massive over-exploitation of bluefin tuna in the 1990s.
Certain fisheries in the high seas are governed by regional fisheries management organisations which fall under the aegis of the United Nations. The one for tuna and tuna-like species, which includes blue sharks and swordfish, is the International Commission for the Conservation of Atlantic Tunas (ICCAT). By the early 2000s the dysfunction of these arrangements was such that the acronym was said to stand for the International Conspiracy to Catch All Tuna.
Meetings were acrimonious affairs. The Atlantic bluefin tuna in particular became the poster child for overfishing and an industry that was incapable of putting long-term management before short-term profits. The fishery was described as a free-for-all or “bordering on pure open access” in the more diplomatic words of a scientific paper on the topic by Norwegian fisheries scientist Trond Bjørndal.
In 2011 the Atlantic bluefin tuna was formally listed as threatened with extinction by the International Union for the Conservation of Nature while the EU was proposing that all trade in the animal should be banned under the Convention on International Trade in Endangered Species.
Today however, the bluefin tuna is, in Bjørndal’s words, “back from the brink”. The fish is no longer overfished and populations in the eastern Atlantic are deemed to have fully recovered. In 2021 it was removed from the endangered species list.
It is a remarkable rebound. Fish began reappearing along the west coast of Ireland in the late 2010s and this year they have shown up in the North Sea for the first time since the 1960s. “This represents a total turnaround from the situation of less than 15 years ago,” wrote Bjørndal. He believed that the pivot came at a meeting in Dubrovnik in 2006 where interventions from a number of countries resulted in the adoption of a recovery plan.
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Grantly R Galland is with The Pew Charitable Trusts, based in Washington, which works, among other things, to promote sustainability in international fisheries, including regional organisations such as ICCAT. He calls the recovery of bluefin tuna “a great success story”.
“The combination of illegal fishing and setting catch limits that were in opposition to scientific advice drove the populations on both sides of the Atlantic down to near collapse,” he said. He believes the prospect of trade in bluefin tuna being prohibited “scared ICCAT into taking real action”.
Three things have been key to the recovery, he says. First, substantial cuts to the permitted catch. Second, a clampdown on illegal fishing (perhaps an equivalent volume to the allowed catch was being taken this way). Now, every individual fish is of such value that it is worthwhile verifiably tracking the movements of each one. “The managers and the supply chain can follow that fish from the boat all the way to its final point of sale,” says Galland.
The final element is a “harvest strategy” that puts rules in place that automatically sets catch limits based on science and which has taken the place of political haggling. “Those three things [are] what has led to the recovery and the broad expansion of the stock, not just back to Ireland but to the UK, Norway, even Iceland”.
The spectacular recovery has not gone unnoticed in Ireland. The Irish fishing industry is in a parlous state due to overfishing, ecological damage to the sea from fishing practices and political mismanagement. Access to quota for bluefin tuna would be a welcome new income stream. However Ireland, having no historic track record in the fishery, is frozen out. Although there is some tolerance for accidental catch, Irish boats can only watch on as boats from other EU countries, principally Spain, enjoy growing access to bluefin in Irish waters.
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At ICCAT, the EU as a whole is granted quota, so for Ireland to gain a share would require other countries to make sacrifices. Minister for Agriculture, Food and the Marine Martin Heydon, in a response to a parliamentary question earlier this year, said the Government was trying to open negotiations but conceded changing the status quo was “difficult”.
“It is a very difficult problem to solve,” Galland agreed. However, he said: “There are good Irish scientists participating in the ICCAT science process.”
This, he said, was “giving Irish stakeholders a chance to better describe the fishery which may contribute to a conversion in Brussels or at ICCAT down the road”.
He is referring to the Tuna Chart programme led by Inland Fisheries Ireland (IFI) which has, since 2019, been authorising a small number of charter angling vessels to catch bluefin tuna, tag them and release them back to the water.
In 2025, 293 bluefin tuna were tagged and released by 22 charter skippers. Boat owners must undertake training to ensure that animals are handled correctly while IFI carries out patrols and surveys to monitor for illegal activity. Skippers can take paid sport fishers on board and day fees can be up to €900 per person for a full day’s fishing.
Ciara Wögerbauer is a researcher with IFI who helped to design the Tuna Chart programme. She emphasises the scientific focus of the programme and points to a new paper published in the journal Fisheries Research detailing the latest findings. “We wanted to understand where bluefin were. Had the distribution changed over time? Were they turning up regularly and predictably?” she said.
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She describes the licensing and monitoring as “tightly regulated”. Tuna are brought alongside the boat and taking them out of the water is prohibited. The welfare of the animal is “paramount” and the available data show that the fish survive the process well.
Fish are tagged with a unique identifier and released so that if they are later recaptured this can reveal valuable information about movements in space and time. To date, two tagged fish have been recaptured, one off the north coast of France and one off the south coast of Spain. Ireland has a challenge ahead if it is to win a share of bluefin catches but, says Wögerbauer, “as long as we don’t have a quota this is the way that angling can be facilitated.”
The success of Atlantic bluefin tuna recovery gives us a number of lessons for fisheries management in general, the most important being that scientific-based exploitation and strict enforcement of rules can see a rapid recovery in fish populations. The other is that sport angling can provide good income for coastal businesses while contributing to scientific knowledge of marine life. The licensed catch-and-release protocol could be expanded to other threatened species such as sharks and skates.
It’s a rare good news story for the ocean that has benefited both fisheries and the fish itself, a model that can surely be repeated elsewhere.
