Spread of Diseases & Ocean Pollution
DISEASE
Cramming thousands of fish in cages creates a high risk of disease. When drugs to treat disease do not work or are not available, diseases can infect wild marine life. In addition to sea lice from salmon farms, Whirling disease has spread from farmed to wild trout in more than 20 Northeastern and Western states. This parasite, which deforms and disorients young fish, has killed up to 90 percent of wild trout in some western U.S. streams. Disease transmission is a particularly difficult problem to assess and prevent, because very little is known about disease mechanisms among wild fish.
POLLUTION
Untreated fish waste, excess feed, and fish carcasses empty directly from cages into the ocean. Based on the little research conducted so far, this waste has been shown to cause oxygen-depleting algae blooms, pollute the seafloor, and alter fragile habitats. Researchers do not know whether the oceans, which have already been damaged by industrial and agricultural pollution, can absorb yet another source of waste.
LEARN MORE