It was fished in abundance until the beginning of the 20th century. All the French rivers were then teeming with wild salmon, to the delight of fans of the reel. But the landscape has since changed a lot, and the king of rivers has today almost disappeared from all watercourses. Ditto in North America and throughout northern Europe, where Atlantic salmon has become rare. With a global population that fell by 23% between 2006 and 2020, the species has just moved from the “least concern” category to “near threatened” according to the red list established each year by the International Union for Conservation of Nature.
The reasons for this decline are numerous. Climate change of course, with the warming of fresh and marine waters and the scarcity of its prey. But also human activity, with overfishing at sea and pollution of rivers. And if that wasn’t enough, many dams have also been erected over the last century, clearly not helping the salmon in their migration. This explains why wild salmon have deserted the Loire, Dordogne, Garonne and Allier for several years. Last year, only 113 salmon were counted across the entire Loire basin, according to figures from the Logrami associationwhile catches were around 4,000 to 5,000 at the beginning of the 20th century.
“The holy grail for a fisherman to catch one”
But as in Asterix, a small Gallic village tries to resist this progressive extinction of the species. With a few rivers in Normandy and the Basque Country, Brittany is indeed a last refuge for this great traveler with his silver robe. “Salmon is found in around 25 rivers in the region, all west of a line between Saint-Brieuc and Vannes,” indicates Jean-Yves Moëlo, president of the Bretagne Grands Migrateurs association. In the watersheds of the Armorican massif, wild salmon seem to have found a favorable environment. “It’s already easier for him to get around because there are no large dams in Brittany,” says Nicolas Jeannot, technician at INRAE. “And it finds here a rather favorable habitat to reproduce and grow,” continues the salmon specialist.
But don’t think that salmon see life in Brittany all rosy. Because here too, stocks are dwindling, fishermen observe every day. “In the 1980s and 1990s, you could see around fifty and catch three in the same day,” assures Jean-Yves Moëlo, former president of the Morbihan fishing federation. There, in ten years, I must have caught only two or three. » “It’s the holy grail today for a fisherman to catch one,” smiles Jean-Luc Pichon, of the Water and Rivers of Brittany association.
The salmon return in fewer numbers and less strong
To see this decline, head to the Scorff migratory fish monitoring station. It is in this Morbihan river, one of the four reference rivers for wild salmon in France, that Nicolas Jeannot and his teams have been studying salmonids since 1994. In particular their extraordinary journey, which starts in the Breton rivers. The fry, the baby salmon, grows there to become a parr before smoltification, a strange metabolic process allowing this freshwater fish to adapt to sea water. Then head to the Faroe Islands, with thousands of kilometers, where the salmon will spend one or two years at sea (one year for a castillon and two years for a spring salmon), before returning to its native river to reproduce.
But for several years, the number of salmon that manage to return has been extremely low. “For every hundred little ones who leave, there are barely ten who come back, compared to 30% previously,” worries Jean-Luc Pichon. And when they manage to return to Breton rivers, the salmon are also less fleshy than their ancestors. Over the past two years, juvenile production has also collapsed with abundance indices which have never been so low. “All the indicators are red,” underlines Jean-Yves Moëlo, calling on all stakeholders to mobilize “to save this heritage species. »
President of the Bretagne Grands Migrateurs association does not, however, fear an extinction of the species in Breton rivers. “Wild salmon are extremely resilient fish, and in the future they may adapt their survival strategy and no longer go to sea,” he says. A not so crazy scenario according to Nicolas Jeannot: “We learn more every day about this species which surprises me every time”.