A new assessment from the Norwegian Institute for Nature Research found genetic material inherited from escaped farmed salmon in two-thirds of the wild Atlantic salmon populations studied along Norway’s coast.

Researchers examined samples from 73,522 salmon across 263 populations. They classified 19 populations as having poor genetic integrity and 73 as very poor. While more populations improved than declined since the previous assessment in 2023, the findings show how widespread interbreeding with escaped farmed salmon has become.

Researchers warn that this genetic mixing can make wild salmon less able to adapt to environmental change and can threaten the productivity of their populations. They also caution that a single major farm escape could have severe consequences for one or more wild populations.

This study concerns Atlantic salmon in Norway. For Wild First, it is a reminder of why preventing farmed salmon escapes matters as Canada works toward its commitment to ban open-net pen salmon aquaculture in B.C. coastal waters by June 30, 2029.

Read the full article from the Norwegian Institute for Nature Research.