Europe's Atlantic bluefin tuna populations have made a reassuring comeback after nearly collapsing two decades ago. Today, tight international controls keep fishing sustainable across the Mediterranean and East Atlantic — under close scientific oversight.
Twenty years ago, Europe’s bluefin tuna stocks were in crisis. The booming global sushi and sashimi market had driven prices of this luxury delicacy to extraordinary heights. Industrial fishing fleets operated across the Mediterranean without effective oversight, de-facto ignoring sustainable limits.
"There were way too many boats catching way too much bluefin tuna," explains Tristan Rouyer, a fisheries ecologist at IFREMER. "Basically, there was no control. Illegal fishing occurred absolutely everywhere. Lots of small fish were caught, lots of big ones, without really knowing how many.”
Scientists raised the alarm about the species' rapid decline, while environmental activists clashed with the fishing industry, demanding an end to what they called the plundering of Mediterranean waters. The campaigns brought public attention to the crisis, forcing governments and the fishing industry to act.
The plan that worked
After first attempts to bring order to chaos failed, a comprehensive tuna recovery plan took effect in 2007 across the entire region. Introduced by the International Commission for the Conservation of Atlantic Tunas (ICCAT) and enforced by the European Union authorities, the plan included strict quotas, reduced fishing fleets, limited catching seasons, and international inspections.
As a result, estimated bluefin tuna catches dropped from approximately 60,000 tons to 10,000 tons in 2007. Fish populations started to recover faster than even fishery ecologists expected. As stocks rebuilt, fishing gradually increased again, but this time within carefully managed sustainable limits.
To this day, the fishing industry keeps operating under tight control.
In Sète, France's main bluefin tuna fishing hub, every landed fish of this species must be weighed, labelled, and tracked from boat to plate. Large seiner vessels mostly sit idle at the docks: their quota limits restrict them to just a few weeks of fishing each year.
What do fishers think of these restrictions? Bertrand Wendling, general director of a major fishing cooperative SaThoAn, says that the sector supports the measures and that its commitment to sustainability is confirmed by independent international certifications. "The stock is doing so well that quotas kept gradually increasing by 20% over several years," Wendling notes. "Today, we have relatively high catch levels that are sustainable because we no longer catch small fish. Most importantly, everything is extremely regulated.”
Scientists keep watch
Fishery management decisions aren't based solely on industry catch reports, which can be misleading since fishing vessels operate in areas where fish are most abundant. For a more representative analysis, scientists use special monitoring techniques to track tuna populations. Researchers from IFREMER conduct annual tagging programmes, attaching electronic devices to individual fish to study their migration patterns.
"This is the only tool that really allows us to track individual tuna migrations," says Tristan Rouyer. "We program it to record temperature, pressure and light. With this information, we can reconstruct the animal's path.”
Aerial surveys complement the tagging work. Scientists fly small aircraft over the Mediterranean, counting tuna schools feeding at the surface and comparing the sightings year to year. The results have been remarkable.
"We've seen a huge increase in abundance between 2000 and 2020," Rouyer says. "In the 2000s, during a complete season — eight to twelve flights — we would see 60 schools. In the 2020s, we had flights where we saw more than 300 schools per flight!”
Since 2020, the recovery has stabilised, though scientists continue monitoring to determine whether this represents a plateau or the beginning of a decline.
What could still go wrong
So what’s the key to keeping this going? Scientists say, the bluefin tuna comeback will only last if we avoid repeating past mistakes. Management and control seem to be working now, but researchers warn against getting too comfortable and letting fishing go back to the wild west days.
"We know that illegal fishing is starting to develop again in certain places," notes Rouyer. "We really need to keep an eye on this aspect. It's a really important safeguard. If we lose control of this fishery, we'll probably return to the problems.”
For now though, Europe’s bluefin tuna is widely seen as proof that scientists, authorities, environmental activists and the fishing industry can work together to save a species on the brink.
Read more
