I’m writing in response to the recent letter “Salmon farms not harming wild salmon stocks” by Miranda Pryor of the Newfoundland Aquaculture Industry Association.
In responding to Paul Michael White’s call for improved aquaculture leadership and a move towards more sustainable land-based operations, Pryor claims that ocean-based aquaculture impacts on wild salmon populations are limited, and that this is backed by scientific evidence.
But she fails to provide any evidence in support of her argument, and in fact a number of her statements are demonstrably false.
Pryor claims that Department of Fisheries and Oceans (DFO) science has documented a range of other human activities as the main threats to the recovery of wild salmon populations, and leaves aquaculture off her list of threats, implying that DFO does not identify aquaculture as a threat.
But DFO’s assessment of the recovery potential for threatened salmon populations on Newfoundland’s south coast (published in 2012) tells a different story. The document lists “ecological and genetic interactions with escaped domestic Atlantic salmon” as one of the factors likely having an impact on south coast populations and indicates that “even small numbers of escaped farmed salmon have the potential to negatively affect resident populations.”
Escaped farmed salmon have been found in Conne River and, last spring, a significant number were found in a number of rivers on the Burin Peninsula, with DFO going so far as to ask anglers to help capture and collect samples from these fish.
The DFO document also indicates that “aquaculture sites have the potential to affect fish habitat” and that “a growing salmonid aquaculture industry in this area may limit the quantity and quality of habitat” within Bay d’Espoir, where most aquaculture operations are currently located. With a major expansion of aquaculture operations to other bays along the south coast planned for the near future, the effects of habitat loss will soon be felt by other populations as well.
Pryor also claims that science on a “global basis” does not support the contention that farmed salmon decimate wild salmon, but does not back this claim up with reference to any studies.
In fact, dozens of scientific studies published over the past 15 years have continually shown that wild salmon populations do not do well when exposed to salmon aquaculture operations.
The most “global” of these studies was conducted by J. Ford and R. Myers at Dalhousie University in 2008. These researchers compared the survival of salmon and sea trout in areas with salmon farming to adjacent areas without farms in Scotland, Ireland, Atlantic Canada and Pacific Canada.
They found that salmon and sea trout populations exposed to salmon aquaculture sites showed significant declines in survival and abundance (in many cases the decline was greater than 50 per cent) compared to populations not exposed to aquaculture.
They conclude that “salmon farming has reduced survival of wild salmon and trout in many populations and countries” and that “reducing impacts of salmon farming on wild salmon should be a high priority.”
Studies conducted since the Ford and Myers study have continued to demonstrate impacts of aquaculture on wild salmon. The weight of scientific evidence for the impacts of aquaculture on wild salmon was recognized by DFO in the document noted above which states that “there have been many reviews and studies showing that the presence of farmed salmon results in reduced survival and fitness of wild Atlantic salmon, through competition, interbreeding and disease.”
Pryor also claims that the aquaculture industry continues to support efforts to protect and conserve wild populations of Atlantic salmon, but again fails to back this claim with any facts.
Rather than making such unhelpful and unsubstantiated claims, it would be more productive if the industry could provide some details on: 1) what specifically the industry has done to better understand the impacts of their operations on wild salmon populations in Newfoundland; 2) the steps that have been taken to reduce or mitigate these impacts; 3) the results of followup studies to monitor the effectiveness of these actions; and 4) future plans to continue to address this issue.
This information would be welcomed by the many members of the public who are starting to demand answers.
It’s time for the people of Newfoundland and Labrador to engage in an open and honest discussion about the sustainability of the aquaculture industry and its future direction.
But how is such a discussion possible when the industry refuses to acknowledge the weight of scientific evidence or admit that what they consider to be “best practice” is not good enough? The tide of public opinion is swiftly turning against open-sea salmon farming, and the technology for more sustainable land-based closed containment systems is developing rapidly.
The aquaculture industry is not doing itself any favours by sticking its head in the sand and refusing to engage in open and honest discussions about sustainability problems and their potential solutions.
Dr. Stephen Sutton
Centre for Sustainable Tropical Fisheries
James Cook University, Queensland, Australia