This May 26, 2022 begins the bluefin tuna season. Until July 1, the 23 tuna seiners from Sète and the neighboring ports of the Gulf of Lion will set off on a campaign to track down the migratory animal which gathers in the Mediterranean every spring to reproduce. These powerful boats are under surveillance both by GPS and by observers on board. It is that we do not laugh with the catch quotas for a species with high market value. The International Commission for the Conservation of Atlantic Tunas (ICCAT) authorizes for this 2022 season the capture of 36,000 tonnes of Thunnus thynnus. The French share is 6,000 tonnes, of which 3,500 tonnes are reserved for seiners (large fishing nets that surround the banks) for which this is the only activity and 660 tonnes for small longliners in the coastal fishing of the Gulf of Lion. It may not seem like much. It’s actually a lot. “In 2014, the overall quota was 13,500 tonnes”recalls Bertrand Wendling, general manager of the fishing organization (OP) Sathoan (Sardine-tuna-anchovies) based in Sète (Hérault).
Some of these boats accommodate scientists specializing in the species. “We are the ones asking for them“, specifies Bertrand Wendling. Ten years ago, the approach was not natural. The “war of the tuna” opposed then the fishermen to the environmental NGOs specialized in the protection of maritime resources with the scientists stuck in the middle who tried to understand the methods by which they estimated the amount of fish in the sea and tried to objectively justify their cries of alarm.For 20 years, fishermen disputed these calculations, claiming that there was always so much bluefin tuna to come reproduce in the Mediterranean despite reports of a declining resource and especially ever smaller fish. Everything is forgotten. What happened? “When the news is good, everything is fine“, smiles Bertrand Wendling. Painfully imposed in 2014, the recovery plan has worked beyond expectations. Less hunted down in its fresh places, the species has recovered. And the catch quotas have increased again. “It has been demonstrated that the recommended management method has indeed the expected results”, notes Tristan Rouyer, researcher at Ifremer Sète.
A common interest in better understanding how tuna live
Common ground has emerged.
This May 26, 2022 begins the bluefin tuna season. Until July 1, the 23 tuna seiners from Sète and the neighboring ports of the Gulf of Lion will set off on a campaign to track down the migratory animal which gathers in the Mediterranean every spring to reproduce. These powerful boats are under surveillance both by GPS and by observers on board. It is that we do not laugh with the catch quotas for a species with high market value. The International Commission for the Conservation of Atlantic Tunas (ICCAT) authorizes for this 2022 season the capture of 36,000 tonnes of Thunnus thynnus. The French share is 6,000 tonnes, of which 3,500 tonnes are reserved for seiners (large fishing nets that surround the banks) for which this is the only activity and 660 tonnes for small longliners in the coastal fishing of the Gulf of Lion. It may not seem like much. It’s actually a lot. “In 2014, the overall quota was 13,500 tonnes”recalls Bertrand Wendling, general manager of the fishing organization (OP) Sathoan (Sardine-tuna-anchovies) based in Sète (Hérault).
Some of these boats accommodate scientists specializing in the species. “We are the ones asking for them“, specifies Bertrand Wendling. Ten years ago, the approach was not natural. The “war of the tuna” opposed then the fishermen to the environmental NGOs specialized in the protection of maritime resources with the scientists stuck in the middle who tried to understand the methods by which they estimated the amount of fish in the sea and tried to objectively justify their cries of alarm.For 20 years, fishermen disputed these calculations, claiming that there was always so much bluefin tuna to come reproduce in the Mediterranean despite reports of a declining resource and especially ever smaller fish. Everything is forgotten. What happened? “When the news is good, everything is fine“, smiles Bertrand Wendling. Painfully imposed in 2014, the recovery plan has worked beyond expectations. Less hunted down in its fresh places, the species has recovered. And the catch quotas have increased again. “It has been demonstrated that the recommended management method has indeed the expected results”, notes Tristan Rouyer, researcher at Ifremer Sète.
A common interest in better understanding how tuna live
Common ground has emerged. “We have every interest in better understanding how fish live, what makes it present here and not there, why it is more or less abundant depending on the year“, details Bertrand Wendling. The scientists themselves are not numerous enough and do not have enough money to finance campaigns which would allow them to better understand important animals in the marine ecosystem. “With the fishing boats, we can set up ambitious programs”, greets Tristan Rouyer. Thus, this researcher was able for the first time in the world to equip individuals with beacons to follow them on a journey that can circle the entire North Atlantic. “These operations are not obvious. The fishermen have their work to do which is intense because the campaign is short, and often, in order to be able to take our measurements and set up our equipment, we ask them to do maneuvers that are unnecessary for them”, continues Tristan Rouyer. The researcher’s new program focuses on the physiology of fish. This spring, he will equip tunas with devices that measure the heart rate of animals that can dive up to 1,000 meters deep in order to unlock the secret of these athletes.
A longline.Credits: Sathoan
Two other scientific programs focus on bycatch in tuna fishing. The sector has indeed changed a lot. In 2007, “drift-gill” nets with which tuna were caught were banned because of their devastation on all marine fauna. With this technique, a lot of unwanted species were caught. “From 2009, longline fishing has developed, these long lines fitted with hookssays Bertrand Wendling. 80 trollers now use this technique, but with impacts on two unresearched species, the blue shark Prionace glauca and the stingray Dasyatis pastinaca”.
Electronics to the rescue to avoid the death of sharks and rays
Fishermen are therefore turning to scientists to find solutions. The first action consisted in making professionals aware that these unwanted captures had an impact on two species considered endangered by the International Union for Conservation of Nature (IUCN). The Echosea program thus consists of recording accidental catches to identify the fishing areas where this happens most frequently and to encourage fishermen to release these animals. “To do this, we ask them not to take the rays and sharks on board but to unhook them from the hook in the water, which is not easy”, recognizes Bertrand Wendling. But are these selachians still alive or dead after the release? To find out, the Pobleu project will consist of developing an electronic system placed on the line that recognizes the species of fish that has just been caught so that the fisherman can act quickly to release the unwanted catch. “A caught tuna dives deep and violently, while a shark will circle around and a ray will be much less violent”, explains Tristan Rouyer. The system called SmartSnap is developed by the CNRS’s computer science, robotics and microelectronics laboratory in Montpellier and should soon be tested at sea.
The fishery expects to benefit from these environmental efforts. Line-caught bluefin tuna is labeled both by the public “sustainable fishing” eco-label and by the private distinction “Marine stewardship council” (MSC). After clashing violently, fishermen and scientists today welcome a fruitful collaboration for all.