Last month, Mainstream Canada announced that over 500,000 British Columbia salmon have been culled in the past month due to a viral outbreak in the region. The disease, called infectious hematopoietic necrosis or IHN, is sometimes compared to rabies and affects a number of different trout and salmon species.
The farm wasn't the only one to report the virus amongst their fish population. Another local fishery announced a low positive result for the virus but did not report a similar cull. A low positive does not necessarily mean the fish are sick, and further tests are necessary to determine whether the population is safe.
Although the virus does not harm humans, it is obviously detrimental to the affected farming operations. British Columbia is already the highest-cost producer of salmon in the world, and further outbreaks in the region could be catastrophic for local farmers.
The company claims that wild salmon introduced the virus into the population, which lives in netted-off areas off the coast. The nets and other equipment will be destroyed along with the fish to ensure the virus is not passed on to the new generation of salmon.
Environmental groups claim that the Canadian government covered up findings last year that showed another debilitating salmon disease, infectious salmon anemia, was detected in local waters. A local professor published his positive findings in 2011 in Science, but the government's corroborations came back negative. While a serious outbreak would harm the industry, deliberately hiding the problem would likely lead to further detrimental culls.
Aquaculture is one of the most rapidly-expanding areas of production animals, and pharmaceutical companies are beginning to take notice. At the moment, only a handful of drugs are approved for use in the US, although more are available in larger markets.
Learn more about trends in fish health and drug regulation at the World Animal Health Congress.