Norway’s Atlantic salmon risks going the way of the panda

EACH SUMMERIMRIMRAI, on the banks of the Orkla river in western Norway, the Grindal Salmon Lodge attracts anglers seeking a bucket-list fish. The season for wild Atlantic salmon, which swim upstream from the ocean, starts on June 1st, and for months after, the whipping of fly-lines accompanies the low rumble of white water wending its way down to the fjord below.That is, at least, how it normally goes. But in June, just three weeks after the river opened, angling for salmon was banned on the Orkla and 32 other Norwegian waterways, as well as on vast stretches of coastline. There simply weren’t enough fish.Wild Atlantic salmon stocks have been in decline for decades, with the two lowest annual returns recorded in 2021 and 2023. But the problem runs deeper than too few salmon making it upstream: those that do are not able to spawn. The data for 2024 are still being collated, but preliminary results across Norway show that the number of mature salmon returning to lay eggs has crashed, boding ill for the next generation. Too many females are dying at sea.Atlantic salmon are anadromous, hatching in freshwater and remaining there for a few years before heading to the open ocean in springtime to hunt and grow. Most return between one and three winters later to spawn, with females rarely coming back before they have spent two years at sea. In any given year, says Per Tommy Fjeldheim, a senior engineer at the Etne river research station run by Norway’s Institute of Marine Research (), more of the larger “two-sea-winter” fish should be seen swimming upriver than the smaller “one-sea-winter” fish that are 95% male. In recent years, however, Etne has been flooded with juvenile males, though large egg-laying females have been scarce.Norway’s multi-billion-dollar fish-farming industry shoulders much of the blame for dwindling wild-salmon stocks. Parasites and disease thrive among captive fish, which then spread beyond their nets. At the Etne river site, which opens out into one of the busiest fish-farming fjords in the country, every single fish your correspondent saw was infested with lice.Escaped farmed fish also pose a genetic risk to their wild cousins. “Wild salmon are adapted to the exact river they spawn in. They’re very specialised,” says Eva Thorstad, a member of the Norwegian Scientific Advisory Committee on Atlantic Salmon. Farmed salmon, by contrast, are bred exclusively for size. “They don’t survive as well in natural environments,” she says. That means interbreeding between the two reduces the quality of wild varieties.But for all the problems caused by fish farming, scientists say it is probably not responsible for the rising death toll among mature salmon. If it were, that mortality would vary with the density of fish-farming enterprises (as rates of parasitism and disease already do). Something else, then, is happening out in the open ocean.One theory is that changing currents and warming seas are affecting the quality and quantity of food available in the waters in which more mature fish swim. In their first year at sea, Atlantic salmon travel to the Norwegian and Barents seas to feed, while older fish tend to visit Greenland’s coastal waters. Data sets from the past year show that schools of capelin, an important prey species near Greenland, have been migrating away from the feeding grounds of Atlantic salmon—perhaps as a result of these changing conditions.Another theory, put forward by Kjell Rong Utne at the , is that predation is to blame. He suggests declining capelin stocks are driving other hungry predators to feast on salmon instead. Here, again, climate change might be responsible. Rising temperatures in the Arctic have meant more ice floes bobbing past the eastern coast of Greenland. Dr Utne wonders whether these might provide the right kind of salmon-fishing spots for seals and other piscivorous mammals.Working out the answers would require researchers to monitor thousands of kilometres of Arctic coastline in the depths of winter. For now, the communities that rely on angling tourism believe the fish-farming industry can do more to help. Many Norwegian scientists agree. At the very least, they say, outdated technologies such as open-net cages should make way for escape-free aquaculture methods. Failing that, other options include more robust lice-killing techniques, such as pouring chlorine directly into rivers.At the Etne river research station, they are doing their part. A floating trap spans the water from bank to bank, with each fish that enters weighed by ecologists clad in chest-high waders. Scale and fin samples are taken for analysis before the fish is re-released, with all the action live-streamed by an underwater camera. To keep the genetic pool intact, any farmed salmon that swim upstream there get clubbed to death with an offcut two-by-four (the club-wielder, Henrik Weiss, explains that the official salmon stick was chewed to pieces by a dog). What is more, says Mr Fjeldheim, footage from the camera is being used to train an artificial-intelligence () model that will be able to tell farmed and wild fish apart. That could help anglers decide which of their catch to release and which to dispatch.Larger-scale solutions are needed. On top of fish farming and climate change, Atlantic salmon also have to contend with increasing numbers of invasive species, rising levels of pollution and acid rain. It is a big ask, even for a fish that’s used to swimming upstream.