I reached out to one of the world experts on salmon farming (Dr Alexandra Morton) based in BC Canada to ask her opinion of the potential impact which as you can see is potentially extremely alarming. I have personally worked as a professional aquaculturalist and I can not agree more that the leak into the wild environment of exotic pathogens is inevitable and is merely a question of ‘when’ not ‘if’.
Here is her reply:
Dear Pete Thank you for your concern about the spread of Atlantic salmon farming, it certainly has had cataclysmic impact on the coast of British Columbia.
However, these RAS systems are part of the solution as they recirculate water and stop the amplification and importation of local and exotic pathogens.
The questions that you might want to have answered is where will the inevitable % of runoff will go. There should be a process of digging perk holes, introducing water with dye where the facility will stand and taking samples from these hole to see where the runoff is going. The ‘Namgis nation did this and I can put you in touch with people there if you want who might remember how this process worked.
Your greatest concern is going to be the spread of exotic viruses, such as piscine reovirus PRV, ISA virus, salmon alphavirus, all pathogens that the industry is riddled with.
They will tell you this won't happen, but it has happed here and elsewhere. They will say there is no evidence of harm to the fish where you are, but that will only mean there is no evidence one way or the other. Every few months there is another paper on PRV and the impact it is having only other species of salmonids, I have found it in herring, but I don’t have the capacity to study its impact.
So here in BC we would say - look RAS systems are spreading, there is one in south Africa, why not adopt this technology here. But on your end you will need to push on where the effluent is going, the industry’s reputation in spreading non-endemic diseases and the value of the marine life around the farm and does it belong in Betty's Bay.
You will need endurance…
All the best,
Dr Alexandra Morton