Fish farms concentrate sea lice

Re: “Fish farms not source of sea lice,” “Sea lice come and go over the years,” letters, Dec. 8. Sea lice drop off migrating wild salmon on the way to spawning grounds, that is true. However, with no fish farms in the area, the abundance of lice would drop due to a reduction in host availability. With opennet fish farms located at or near the mouths of spawning rivers, the lice populations thrive.

This change in the population dynamics of lice poses a threat to juvenile wild salmon as they migrate out of spawning rivers. The threat has been recognized by local First Nations who have intimate knowledge of these salmon runs gathered over thousands of years. The threat has also been backed up by rigorous, peerreviewed scientific research.

Open-net fish farms also pose other threats to salmon and aquatic ecosystems in the form of waste and competition from escapees, and all of these pressures are exacerbated by warming oceans. Anecdotal incidences of lice abundance on adult salmon are not an accurate representation of the effect fish farms have on wild salmon.

First Nations, the Department of Fisheries and Oceans, and aquaculture companies have to weigh the most accurate and complete evidence and act upon it. If there is a significant chance fish farms are negatively affecting wild salmon, we need to do everything within reason to mitigate the problem.

We can do better. Picture yourself 20 years in the future, trying to justify why we didn’t act in the face of significant evidence showing that there is an existential threat to wild salmon. Dave Gill Victoria