In 2023, Norway set up traps in the lower parts of over 50 rivers to capture pink salmon before they could spawn. According to NASCO, an international group focused on preserving Atlantic salmon, about 250,000 adult pink salmon were removed this way. This species was introduced to Russia in the 1950s by the USSR to create a new fishery, with releases continuing until 1979 and again from 1985 to 1999 under Russian management. Despite these efforts to control their spread, pink salmon have continued to move across borders, with sightings reported in Norway, Sweden, Scotland, Ireland, and Iceland. In Norway, the species has established itself, with catches rising from 11,654 in 2017 to 361,548 in 2023. The Norwegian Environment Agency confirmed that pink salmon now reproduce naturally and that young fish have been observed migrating to the sea in 2024. Pink salmon return to spawn every other year, specifically in odd-numbered years. Their numbers have risen dramatically, with catches increasing from 11,654 in 2017 to 14,633 in 2019, then to 151,437 in 2021, and finally to 361,548 in 2023. In August 2021, pink salmon were seen swimming up the Akerselva river in Oslo, a phenomenon that had previously been observed in the Finnmark region of northern Norway. In some northern rivers, NASCO noted that pink salmon now outnumber Atlantic salmon during odd years. The Norwegian Institute for Nature Research (NINA) estimated that nearly 580,000 pink salmon were present in Norwegian rivers and coastal areas in 2023, with 97 percent of them found in Finnmark. These fish die after spawning, and their bodies decompose in rivers that are also home to Atlantic salmon. The Norwegian Environment Agency explains that a pink salmon that does not reach the river mouth cannot spawn, does not interfere with recreational fishing, and does not negatively affect water quality by dying. NINA categorizes pink salmon as a species with "very high risk" in Norway's list of exotic species. The traps used to capture pink salmon are designed to block their movement while allowing wild salmon to continue upstream to spawn. The sorting process is typically done by hand. However, large rivers pose challenges, as seen in the Tana, the largest salmon river in northern Norway, where sonar data suggested about 170,000 pink salmon bypassed a trap in 2023, compared to 7,666 captured. In the Reisa river, where no traps were installed that year, around 10,000 pink salmon successfully spawned. The figure of 250,000 removed pink salmon includes various control methods, not just river mouth traps. In 2025, the Norwegian government expanded its efforts, funding measures in more than 60 rivers—double the number in 2023. NASCO reported the removal of about 161,000 pink salmon in Norway that year, with a decrease in numbers toward the northeast near Russia and an increase in western regions. In the Tana, a 400-meter trap captured nearly 30,000 pink salmon while allowing about 2,500 wild Atlantic salmon to pass through. The exact cost of these efforts remains unclear, but the government had allocated more than 65 million Norwegian kroner to combat the species in 2024. Regarding the impact of pink salmon on Atlantic salmon, NASCO admits that few studies have been conducted, and it would be misleading to directly link the decline of Atlantic salmon to the presence of pink salmon. For comparison, about 323,000 wild Atlantic salmon returned to spawn in Norway in 2024, while 481,463 pink salmon were captured or observed in 2023. The Norwegian Environment Agency cautions that numbers can fluctuate unpredictably and that the fish caught in 2025 likely originated from rivers where the upstream migration could not be stopped in 2023. In Finnmark, where pink salmon catches have decreased, the agency says it is "difficult to say" whether the traps are responsible for the change.