Many of the salmon from the rivers get sick. Their main responsible are lice containing salmon from farms. This is what some Canadian researchers have deduced.
This species of lice inhabits the open sea, behind the backs of their adult salmon. However, it has been observed that in nurseries the infection is widespread, both in adults and juveniles. If wild salmon that go to the sea pass by the nurseries, they present a high risk of contamination, being the degree of infection of young salmon 73 times higher than normal in populations close to nurseries.
The louse causes open wounds on the surface of the salmon. As the infection progresses it can be said that the parasite feeds on live fish, since the salmon feeds at a speed higher than that necessary to reinvent itself, even becoming deadly. In addition, river salmon, at the beginning of their life cycle, are smaller than adults, so their probability of dying is much higher.
Therefore, several experts begin to insist on the need for better farm management, along with the crops, so that wild salmon can survive.