Salmon farm in western NorwayADÈLE MENNERATFish farming is one of the fastest growing food production sectors in the world, but infections caused by bacteria, viruses, and parasites cost the industry billions of dollars in worldwide losses each year. Now, emerging research suggests that diseases of farmed fish may be evolving to become even more harmful to the animals.
Mathias Stølen Ugelvik at the University of Bergen, Norway, and colleagues found that Atlantic salmon (Salmo salar) infected with salmon lice (Lepeophtheirus salmonis) derived from two Norwegian fish farms suffered more-severe symptoms than those infected with lice from wild salmon. “Salmon lice from areas with fish farming appear to have evolved toward a higher virulence as compared to salmon lice from other areas,” study coauthor Arne Skorping of Bergen wrote in an email. The team’s findings were published in the Journal of Evolutionary Biology this month (April 4).
Skorping and colleagues collected lice eggs from farmed and wild-caught salmon, then reared the fish parasites under identical conditions for three generations to ensure any differences between them were genetic. The researchers then infected 55 adult salmon ...
