What the “anti” ocean-farmed salmon idealists don’t like to talk about
Act for Aquaculture, August 27, 2013
The Atlantic Salmon Federation is hosting a fundraiser tonight featuring “new environmentally sustainable Atlantic salmon” to raise money for its Land-Based Closed Containment Salmon Aquaculture Program.
I can’t help being irked by the implication that ocean-farmed Atlantic salmon aren’t environmentally sustainable. The salmon farming industry has been growing fish sustainably for 30 years in this region. I also can’t help being frustrated by ASF’s continued efforts to dupe the public into believing that ocean-farming should be banned and that it’s possible to move all existing salmon farms from the Atlantic region onto land-based tank farms.
They want you to believe that it is possible, and if that was true, the result would be a much more environmentally friendly industry. They are trying to convince you they are the experts in land-based salmon farming and there is much they could teach our region’s salmon farmers.
Are they telling the truth? Let’s see.
ASF doesn’t talk about the fact the industry already has considerable experience in land-based recirculating aquaculture systems (RAS); in fact, they are leaders in the technology with world-class facilities right here. The industry continues to develop this technology in their freshwater farms to maintain healthy broodstock and progeny, and minimize the amount of precious water used in their operations. Local farmers also know this is a costly way of growing fish given the electricity, pumping, heating, labour and infrastructure costs involved. So while it is justifiable for raising broodstock and millions of small fish, the economic facts simply cannot support growing fish on land through all phases of the farm’s production. A DFO study showed that when reasonable assumptions were used in developing an economic model, an RAS based operation was not profitable. Not only that, two recent trials – one in New York and one in Montana – have just closed down.
Even if it were technically and economically feasible, and if the land and access to good water and stable power supply were available (a lot of “Ifs”), it would require the equivalent of approximately 8,500 football fields to accommodate the tank farms needed to grow a modest estimate of 30,000 tonnes of farmed salmon annually in New Brunswick. Those opposed to salmon farming say “Oh, no; it would only take 850 football fields (including end zones) to grow this amount!” How can this be? Because their plan is to grow fish at a stocking density of 100 kg/m3. The local industry recognizes that a natural stocking density should be in the order of 15-18 kg/m3. The 100 number will surely bring about animal welfare issues, let alone lead to potential disease problems. ASF accuses industry of operating “feedlots” but the closed containment systems they are proposing would crowd fish in recycled water at 5-6 times what they would experience in spacious, clean, self-refreshing seawater farms.
I visited ASF’s RAS research facility in West Virginia; some interesting work has been done there, some of which is useful for our broodstock facilities. And yes, it is true that they can grow fish experimentally at high densities in relatively short periods of time, even if the recirculating growing water does not look very appealing. However, what they don’t like to talk about is the fact that it takes 10-15 days of depuration in flow-through fresh water to reduce the musty taste of the flesh. Moreover, during this period when the fish are not fed they may lose four per cent of their body weight and the flesh quality is downgraded as well. Take note if your “new, environmentally sustainable” Atlantic salmon was served smoked at your dinner…smoking the flesh masks the off-flavour.
Yes, there are plans to improve their experimental RAS to eliminate these off-flavours so that long periods of depuration in fresh flow-through water are not necessary. In time, perhaps, this will come about, but it is no easy task to eliminate the bacteria causing the off flavours without eliminating the important bacteria needed to maintain the integrity of the RAS biofilter.
Perhaps what ASF doesn’t like to talk about most are the volumes of freshwater needed for depuration. Perhaps people don’t quite understand what depurating a few thousand fish in running water for 10 days really means. The local industry experts tell us that proper depuration means that the water in the tanks of fish should be drained and replaced on an hourly basis. To do this for 30,000 tonnes, at a proper stocking density of 18 kg/m3 would mean a flow rate of approximately 16,000 ft3/sec for a depuration period of 10 days. To put this in context, the summertime flow rate of the St. John River over the Mactaquac Dam is approximately 7,000 ft3/sec. Or in other words, to depurate the annual New Brunswick production of farmed Atlantic salmon would require the equivalent of diverting more than double the flow of the St. John River in the form of “new” water derived from wells, streams or rivers. With water becoming an increasingly precious resource, this would be an unconscionable waste of such a resource, especially since it could only produce an inferior product that is much better coming from self-replenishing ocean farms.
We haven’t talked about where these land farms would be located – not in Atlantic Canada so what happens to our economy and the thousands of jobs we have here?
To those who attend ASF’s dinner this evening, here’s the truth: moving all of Atlantic Canada’s salmon production to land is not environmentally sustainable or economically feasible. And the salmon grown to market in land-based tanks won’t be anywhere near as tasty as the fresh Atlantic salmon from the ocean that we can buy at reasonable prices in our own grocery stores every day.
Act for Aquaculture Website is at: http://actforaquaculture.ca/who-we-are/
