Salmon farms: Helping or hurting wild salmon?

Update: The 60 Minutes report "Salmon in the Sea" aired on May 11, 2014. Dr. Sanjay Gupta is the correspondent. Peter Klein, producer.

Environmentalists and salmon farmers in the Pacific Northwest are at odds. Environmentalists say the aquaculture business is a threat to the ocean and may spread diseases that could harm wild salmon populations. The farmers counter that they are saving the wild salmon by preventing overfishing and that there is no proof the disease, even if present, will actually kill wild salmon.

Dr. Sanjay Gupta reports from British Columbia, where there are 125 salmon farms sharing waters with one of the largest wild salmon fisheries in the world. Gupta's report will be broadcast on 60 Minutes Sunday, May 11 at 7 p.m. ET/PT.

For this report, Gupta speaks with Ian Roberts of Marine Harvest, the largest salmon farming company in the world. He also interviews Alexandra Morton, a scientist and environmental activist, George Eliason, an Alaskan fisherman and Brian Wallace, a lawyer representing a Canadian government commission examining salmon.