The proportion of escaped farmed salmon reaching spawning grounds remained low in most Norwegian rivers in 2025, according to the latest national monitoring report from Norway’s Institute of Marine Research (IMR).
Researchers surveyed 215 rivers across Norway, the highest number since the monitoring programme began in 2014. Most rivers recorded low levels of escaped salmon, although results in Troms stood out due to a higher proportion of farmed fish.
IMR researcher Kjell Rong Utne said the increase in Troms was likely linked to the escape of 27,000 salmon from a fish farm earlier in the year, shortly before wild salmon began entering rivers to spawn.
The situation improved in Trøndelag compared with 2024, when a major escape incident outside the Trondheim Fjord contributed to elevated levels of escaped farmed salmon in several rivers across Trøndelag and Møre og Romsdal. In 2025, almost all monitored rivers in the region recorded low proportions of escaped fish.
Elsewhere, researchers reported only minor changes from previous years. Rivers with medium or high levels of escaped farmed salmon were concentrated in areas stretching from Vestland to western Finnmark, while all monitored rivers along the Skagerrak coast, in Rogaland and eastern Finnmark recorded low levels.
The monitoring programme is led by IMR on behalf of the Norwegian Directorate of Fisheries and is intended to help authorities identify areas where escaped salmon may pose the greatest risk to wild stocks.