Atlantic salmon invade the Pacific.

• Author: Assadourian, Erik
• Position: Environmental Intelligence - Escaped farmed fish might endanger wild species - Brief Article

Large numbers of Atlantic salmon have escaped from fish farms in Pacific waters and are now thriving in 77 rivers in British Columbia, according to a recent report by the Canadian Parliament's Senate Committee on Fisheries. In introducing the fish, aquaculture proponents had claimed that Atlantic salmon would not be able to compete with native Pacific salmon, but the large number of these invasive fish living in Pacific waters may now pose a serious threat to wild salmon species.

Experts warn that Atlantic salmon could undermine the health of native species by competing for food, interfering with migrations and spawning, displacing juveniles, and digging up eggs. Farmed salmon could also spread diseases, which occur with regularity in aquaculture pens, due to the physical stress and confined conditions.

The report finds that between 1994 and 1998, about 44,000 farmed salmon escaped each year from Canadian aquaculture pens. Canada produces just 3 percent of the world's farmed salmon, and it is likely that the ecological problems are more intense in countries with larger operations. In Norway, the largest farmed-salmon producer, escapes have become so numerous that 87 percent of the 30 rivers currently monitored had...