Fish Farms Threaten Wild Salmon

Fish farming is becoming a more important business as the supply of fish in the wild dwindles due to overfishing. However, fish farming is not completely environmentally benign. Canadian researchers have discovered that parasites called "sea lice" can spread from fish farms into the wild fish population, especially threatening the salmon in the waters off British Columbia and the Pacific Northwest.

A Salmon Cage on the Atlantic

From Issues in Aquaculture, a website about the current state of fish farming.