Much like terrestrial animal farms, fish farms are incubators for disease.
When diseases and parasites from wild populations get into the farmed ones, they can run riot. The high density and low genetic diversity of the farmed fish, and the fact that they stay put in the net pens makes it easy for parasites to quickly spread through the population.
LINK (via: Hakai Magazine)
Here is the story about the lice outbreak in New Brunswick referenced in the article.
It’s a big big dirty business with a big fat expensive PR department regularly placing good news pieces in important big media. Yet another boosting article – “How Scottish Salmon Conquered the World” – is to be found on BBC News online today. Farmed salmon, that is, not the wild salmon that they’re fast killing and usurping. Lice and disease get a mention in the piece, but the industry message / gloss was “We’re on their case and winning”. As petulant, doubting and dissenting teenagers the world over say and I find myself saying now: “Yeah right.”.