A question I have after reading that and several other articles--what is the history of Heart and skeletal muscle inflammatory disease, the hemolytic diseases and liver failure associated with PRV, prior to 1999? Fish farming in BC began in 1970 and by 1993, when were began regular cruising in the area, was common. It is entirely possible that a vector such as the herring or other food fish is a vector in the spread of the diseases.
It seems as if the mortality and unsuitability for market is much higher in the farmed fish. Your points about natural selection are well taken. I would think the density of the farmed fish would lead to a more rapid spread, and more overt disease, as happened in Norway.
I haven't found much about PRV studies in prior years. Probably no knowledge on that. Remember that a lot of the genetic techniques (Polymerized chain reaction, etc.) of identifying viruses and strains are pretty recent, and only very recently common and now relatively inexpensive. My daughter was using these genetic techniques the other day in her lab at the U Washington in Seattle. It wasn't even available when I was her age.
The study I referenced mentioned using archived samples taken during times when methods used weren't so easy. There is some potential for getting very old cans of salmon, etc., and seeing if the virus was present a long time ago, but I am not a salmon scientist and unaware of any studies older than the one I referenced in the region. PRV was identified by other methods earlier, but not much earlier. Maybe if I dig some of those freezer-burne Alaska salmon out of the bottom of my deep freeze....
Farmed salmon are clearly are closed in, may or may not be under more stress (being protected, treated with antibiotics and fed may be less stressful than under predation and near starving?), but population density probably outweighs any of these for virus spread and concentration in tissue. Research results bear this out...the virus spreads easier in pens, and can spread from pens to nearby areas.
There is a correlation between distance to farmed salmon and concentration of PRV. There is no established relationship between concentration of PRV and disease, though it probably makes sense. You find few deformed and diseased fish in the wild, so you can't do a controlled study as you can in pens. Deformed and diseased wild fish don't survive. Actually, if we think of food for Orcas, it is probably the weak salmon that get eaten first. Diseased and deformed fish in pens can survive to be picked out and displayed. All salmon are sorted and rated similar to apples in Wenatchee. The best are sorted out and sold to stores and restaurants whole and maybe exported. In Wenatchee the deformed apples are turned into juice. I don't know what happens to the lesser quality fish, wild or farmed.
PRV is in Alaska, BC, Washington, Chilean, Norwegian, pretty much any fish, not just salmon that has been tested for it. Indeed, it may be the flu virus of fish? I am just speculating on that. I have opinions too. Another factor, identical to flu, is that there are strains, and all aren't likely of similar infectiousness or effect. Again, speculation.
A fish biologist recently told me that fish farming is alive and well in Alaska, producing a billion pounds of product per year, but trying to keep out of the spotlight, and salmon farming is not common and being phased out due to political pressure and the pristine image of wild Alaska salmon.
The image of wild Alaska salmon is somewhat deserved. I can and do pay dearly for it, perhaps a hundred dollars a pound when you think of the costs of going there and fishing, licenses, etc. I am lucky. I can take a filet my family caught out of that deep freeze and prepare it almost any time I want. However, many people don't have the luxury of paying an extremely high price, and farmed salmon in Washington provide jobs and cheaper access to salmon. Eliminating farmed salmon will drive up the price of salmon overall. That is easy for us to force on people when we have the ability to pay for and operate C-Dorys. If we can afford that we can afford a higher price for salmon.
I do not like salmon farming. I not not eat farmed salmon. I do farm oysters and clams on my floats and tidelands and all are not native except the Olympia oyster, which is unproductive. When is the last time anyone ate a native Washington oyster in a restaurant? Whey do many people think differently about farmed shellfish?
My opinions are not entirely based on science. I just think blaming farmed salmon on the decline of wild salmon in general probably misses many of the real issues. Salmon farming is a handy scapegoat when tribal fisheries, commercial fisheries, sport fisheries, and many, many other factors also lead to the decline of salmon.
I do believe that everyone that posted here has the interest of wild salmon, either hatchery stocked or native spawned, at heart. Most of us probably fish, all of us boat, and we want to keep doing so. If we catch or eat salmon, or run our boats, and I do all of these, we are part of the problem, but if we can help with other issues (i.e. habitat, pollution, science, hatcheries, paying for enforcement), we can also be part of solutions.
This is my last post on this. I appreciate everyone's comments and opinions. I'm sure we will see more on this issue in the future, and I am looking forward to the annual run of chinook, coho, and hopefully, lots and lots and lots of pinks, running by my shore. I would fight tooth and nail to keep salmon farming out of Oro Bay, that is for sure. However, I don't think I will have to.
