This post is a critique. The purpose is to give you another point of view and, where available, give you references so that you can then go and do some reading and form your own opinions.
Claim: Fish farm fish cannot interbreed with wild Pacific Salmon.
Response: The available evidence shows that this is true. DFO did some science in 2004, pairing Atlantics with all five species of wild Pacific salmon and steelhead. The table (I can send this as a PDF) makes clear that virtually all matches of eggs and sperm with other species had pretty close to zero progeny. On the other hand, it is alarming to note that steelhead only have about a 50% chance of mating with themselves in laboratory (a lot better than in the wild) conditions.
Why is this important? The most important bellweather species to monitor, and no one is doing this, is steelhead. That is because historically they originated in the Atlantic and moved west between ice ages. They have the closest behaviour to Atlantics and rainbows (oncorhynchus mykiss) are the salmonid most easily infected with ISA, one of the worst fish farm diseases.
Claim: Health experts make no distinction between farmed and wild salmon when it comes to health benefits.
Response: It is hard to answer this one because it is not clear what 'health expert' means. On the other hand, the scientific evidence is clear that farmed fish have much higher levels of PCBs, dioxins, mercury and so on than wild salmon. See: http://fishfarmnews.blogspot.com/2011/12/key-documents-organic-seafood-does-not.html.
And see: http://fishfarmnews.blogspot.com/2011/11/key-documents-levels-of-pcbs-pops-and.html.
As of Feb 7, 2012, Russia has warned that sales of Norwegian fish farm salmon may be banned because of its high coliform and salmonella levels. See: http://themoscownews.com/business/20120207/189436130.html.
Claim: Farmed salmon feeding is monitored by underwater cameras to keep food waste to a minimum.
Response: Closed- container on-land facilities do not allow food (and faeces) to pass out of the container. Feed waste is lower and fish waste is contained, sequestered and can be processed rather than passing to the marine environment. And now, in 2012, the last anchovies and jack mackerel are being caught off Peru for fish farm feed, mostly sent to Asia, rather than fed to humans. http://www.theecologist.org/trial_investigations/1220194/how_our_growing_appetite_for_salmon_is_devastating_coastal_communities_in_peru.html.
The other side of this issue is that when lights and monitoring equipment are installed, local employment declines. That may help explain why there are only 820 jobs in BC fish farms.
The other thing is that herring and salmon are attracted to light. Once inside an open-net cage they are illegal to keep as this constitutes a fishery. That is what Marine Harvest just paid a fine for in Port Hardy, January 18, 2012.
Claim: Salmon are perfect for farming.
Response: If salmon, and this could be any Pacific species of salmon, even Atlantics that should only be in the Atlantic Ocean, are farmed in the ocean in open nets, they are extremely environmentally damaging, and hence, not perfect at all. When farmed on land in closed containers, however, virtually all environmental impacts are eliminated. At that point the claim hinges on feed. Salmon are carnivores and require a diet composed of feed fish or substitutes. Herbivores, on the other hand eat only plant material. These are cheaper and less environmentally damaging to obtain and use. The ideal fish may well be tilapia, easily farmed on land and a herbivore.
Claim: Farmed salmon are better to raise than beef because beef need 8kg of feed per 1kg of steak, while salmon need 1kg to produce 1kg of meat.
Response: This is a comparison of apples and oranges and bananas and cumquats. Here is an alternative assertion: cows are better to raise than Atlantic salmon because when they are born they are far far larger - and immediately harvestable veal - than a salmon egg when it hatches.
Many researchers put the Atlantic food turn-over at 4.68 lbs of forage fish per 1 lb of salmon - that means the astronomical level of 10.3 lbs of forage fish per 1kg of salmon. Do recall from above that global stocks of forage fish for meal are dwindling.
Neil Frazer, University of Hawaii at Mānoa, using the Tacon articles, did the calculation. Here are several pages of web articles on 'feed conversion rates': http://scholar.google.ca/scholar?q=Tacon,+A.+G.+J.+and+Metian,+M.+%282008%29,+Aquaculture,+285:&hl=en&as_sdt=0&as_vis=1&oi=scholart&sa=X&ei=lhgzT733CsTkiAL14ryMCg&sqi=2&ved=0CBoQgQMwAA.
There is, of course, a search on for alternative plant oils. The question is: do we want soybean, canola, palm or corn oil in fish? While thinking this dietary comparison over, think of the documentary: Fish.Inc, er, Food.Inc. It makes a convincing case that feeding cows corn makes for higher levels of e-coli in the entire beef food chain.
On the lighter side, it may amuse you to know that researchers are arguing about whether plant oil fish food makes Atlantic salmon suffer more heart attacks! See: http://www.fishnewseu.com/latest-news/world/6959-commercial-high-vegetable-content-salmon-feeds-do-not-cause-heart-problems-says-skretting-researcher.html.
Claim: Salmon feed is designed to minimize the use of ingredients from wild fish stocks while providing farmed salmon with a perfectly balanced diet. In the wild salmon are voracious carnivores, it’s estimated that they consume 10 times their weight in smaller fish throughout their lives.
Response: As the previous response indicates, the feed issue is more murky than this perky explanation of fish farm food indicates. And the wild salmon comparison seems to argue that nature is wrong to allow wild salmon to eat what they naturally eat. I think not.
Claim: Farm feed uses a lot of non-marine proteins to lessen the impact on wild feeder fish stocks, which means our fish eat fewer wild fish. And because many of the ingredients are locally sourced, salmon farmers are able to support Canadian and other North American farmers, provide a healthy diet to their animals and protect wild stocks all at the same time.
Response: Fish feed has no choice but to evolve because fish feed companies have fished down the available forage fish stocks in other parts of the world. Do note that a Norwegian company is among those in Peru fishing down the stocks of forage fish that should be eaten by humans.
Some of the new proteins include chicken feathers, chicken waste and so on. Based on the research above, I would want to investigate fish feed components before accepting the claim. We don't grow much soybean, canola, palm or corn for oil in BC. And it is the fish oil that is the important constituent, not the fish meal.
As for protecting wild stocks, I don't recall fish farms ever being allowed to catch herring and so on in BC. As for wild salmon, not catching non-existent forage fish in other parts of the world has no effect on wild salmon here because, well, they are here, not there.
Claim: Salmon farmers would never add chemicals to their salmon.
Response: Google this to find pages of articles on chemicals in farmed fish: http://www.google.ca/#q=fish+farm+chemicals&hl=en&prmd=imvns&ei=-ko0T43vJe7ZiALUpvGdCg&sqi=2&start=10&sa=N&bav=on.2,or.r_gc.r_pw.r_cp.,cf.osb&fp=2e2c6fe6af1fe05c&biw=1024&bih=592.
The main reason why farmed fish have greater amounts of chemicals is the oil in their feed that concentrates the persistent organic pollutants (POPs). Then there is Slice, vaccines, hydrogen peroxide baths and so on. In Nova Scotia, Cooke Aquaculture currently is being charged with using the illegal chemical, cypermethrin, to kill lice. And in Norway, they have given up on the old chestnut that lice aren't a problem - because Slice no longer works - and have invested $44 million in finding new chemicals. Malachite green has shown up in Chilean salmon exports. And in Chile use of common antibiotics like tetracycline has resulted in passing of genes for resistance to these human medicines to bacteria that infect dogs and human beings - rendering human antibiotics useless.
Claim: Nor are there any dyes—both farmed and wild salmon get their colour from the pigments they ingest as part of their diet.
Response: In the past, feed manuals came with photos of fish flesh colour chemicals. You ordered fish colour based on which colour you liked best and the feed had the 'dye' in it. Now, carotenoids and chiral isomers are added to fish feed. These are the same chemicals as those in real feed, say, krill, so technically farm fish do ingest colour as part of their diet.
One feed company in Oregon, in Bio-flake, advertises that it has the krill from the pristine waters of Antarctica - natural colour. I find it appalling that in the most pristine area of the world the food chain is being worked down so far that euphasid shrimp are the target. The only thing below is plankton and blue-green algae.
Claim: For a modern salmon farmer their salmon’s health is one of their biggest priorities.
Response: Yes, fish health is important, however, the world expert on ISA, Dr. Fred Kibenge, has said: Aquatic animal disease is part and parcel of aquaculture.
Mary Ellen Willing of the BCSFA has said that only 1.5% of salmon die of infection. This is the 'natural' rate for ISA and after a few years it explodes. Chile lost 500 farms, some quarter of a billion fish farm fish, 2008 - 2010. The BC fish disease tables show that since 2003 fish farms have lost 29 million fish to all causes. See: http://fishfarmnews.blogspot.com/2011/11/fish-farm-fish-deaths-in-norway.html. The provincial tables can be found here: http://www.cohencommission.ca/en/.