.Severe skeletal damage recorded in fish from Troms and Finnmark.
Havforskningsinstituttet researchers have reported the first documented cases of severely deformed adult pink salmon in Arctic waters, following findings in Troms and Finnmark.
The fish were captured in 2025 during monitoring under the NALO programme for salmon lice on wild salmonids. According to marine scientist Per Gunnar Fjelldal, the spinal deformities observed are significantly more serious than previously reported cases.
“These deformities significantly affect swimming ability and survival. It is quite remarkable that these fish have survived to adulthood,” Fjelldal said.
He added that the current cases represent “far more severe deformities than have been reported earlier.” Pink salmon are active swimmers undertaking long migrations, and spinal damage increases vulnerability to predation.
Deformities in fish from Arctic waters are considered rare. While research into fish deformities dates back several centuries, deformed fish in Arctic marine environments were only first recorded in 2024. Those earlier cases involved polar cod and the flatfish species Hippoglossoides robustus.
Fjelldal said the findings may indicate environmental change in the areas where the fish live.
“This suggests that the environment the fish inhabit is being affected and is changing,” he said, adding that the cause of the deformities in pink salmon is not yet known and will be subject to further investigation.
Samples have been collected for DNA analysis, and the specimens have been incorporated into the fish collection at the University Museum of Bergen to allow for future research.