The Salmo domesticus is a salmon that can grow twice as fast as that of the natural species of salmon. In Norway, breeders placed salmon in “cages” and breed them with the intention of increasing growing speed. After 14 years of breeding, they had a salmon that grew twice as fast as the original stock. The productivity of this salmon led to the development of an international industry as Norway did business with Chile and there are now salmon there.
This fish is a curse.
When it escapes from the farms it wreaks havoc on local wild fish populations by competing for resources. When it comes to survival for the sake of reproduction, this salmon does poorly against strong currents that its native brethren use for spawning grounds. This salmon is not native to some of the regions that it is now farmed.
There is also the issue of feeding these salmon and the waste that they produce. Many wild fish are killed to make feed for these salmon lowering the wild populations and putting undue pressures on those habitats. The waste that is left behind leaves zones of low productivity and could be considered a health risk.
The issue with this situation is that it is a global industry. There is money that can be made by farming salmon so the consequences do not matter to the industry. It is allowed by the governments because the industry is providing revenue to the economies; remember FDA’s approval of DDT pesticides which supported the agricultural industry. Even when there is some form of governmental oversight, there are usually members of the board that used to work for the large companies of that industry or later leave the oversight boards to be employed by those companies; think of the FDA’s approval of GMOs and its revolving door relationship with Monsanto.