John Volpe has published many papers on escaped Atlantic salmon in BC. Here is an earlier post on this site, the original classic paper: http://fishfarmnews.blogspot.ca/2017/09/atlantic-salmon-breed-in-bc-rivers.html.
Volpe et al, including Fisher, have published many more over the years. A recent paper, 2014, has the scary subject matter that farmed Atlantics are indeed now wild and reproducing in BC: https://link.springer.com/article/10.1007%2Fs10530-014-0653-x.
Fish farms say no escapes have occurred in years, DFO does not keep stats, and there is no independent check on the veracity of fish farm claims. In Norway, however, the same companies use fish that the government just needs to DNA check them and the fish farm, usually Marine Harvest, Cermaq and Grieg Seafood is fined for not reporting.
The Norwegian government started doing DNA testing and fining fish farms because there is a history of failure to report escapes - and other things - by Marine Harvest, Cermaq, Grieg Seafood and others.
So why would Marine Harvest, Cermaq or Grieg Seafood be any more honest in another country than their own country where they are not honest? And soon, unless Marine Harvest gets back to me, I will be posting on what they told the press, but are not willing to back up their communications spin person in BC. In other words, there may be no point believing anything a fish farm company says. I'll let you know in a new post.
The 2014, Volpe/Fisher paper is: Occupancy dynamics of escaped farmed
Atlantic salmon in Canadian Pacific coastal salmon streams: implications
for sustained invasions.
The Abstract is:
"Farmed non-native Atlantic salmon (Salmo salar)
is the largest agriculture export product of British Columbia, Canada.
Chronic low-volume escapes of salmon from farms into Pacific waters
(“leakage”) are typically undetectable (Britton et al. 2011).
Analysis of escape-reporting from farmers indicates that reports
greatly underestimate the true number of Atlantic salmon inadvertently
released from open-net pen rearing sites (Morton and Volpe 2002).
To quantify the spatial extent of escaped Atlantic salmon in Canadian
Pacific rivers, we systematically snorkel-surveyed 41 known Pacific
spp.)-supporting rivers and creeks on Vancouver Island over a span of
3 years. We estimated and accounted for imperfect detections using
multi-season occupancy models. We detected Atlantic salmon in 36.6 % of
surveyed rivers. After accounting for imperfect detection, occupancy
models estimated that over half of surveyed streams across the study
area contained Atlantic salmon, and that 97 % of streams with high
native salmon diversity were occupied by Atlantic salmon. Even in
intensive snorkel surveys, Atlantic salmon are detected in occupied
streams only 2/3 the time, suggesting abundance and distribution of
non-native salmon is greater than indicated by the only existing data.
Further, Atlantic salmon are more likely to occupy streams with high
native Pacific salmon diversity—and more likely to maintain occupancy
across years—potentially increasing competitive pressure on native
salmonids. Understanding local biotic and abiotic predictors of Atlantic
salmon occupancy, stream colonization, and local extinction requires
more data; the same is true for the effects of escaped Atlantic salmon
on local salmon diversity and sustainability. These data for the first
time show that Atlantic salmon occupy Pacific coastal rivers for
multiple years. The impact of Atlantic salmon occupancy in British
Columbia rivers must be factored into policy decisions regarding the
future of salmon farming in the provincial waters."
Look at Table 1 for the stats by state/prov on juvenile/adult Atlantics.
Here is what Living Oceans, a BC ENGO has to say on this subject:
"Farmed Atlantic salmon were estimated to be present in over half of
surveyed rivers and streams according to modeling conducted for an
article recently published online in the journal Biological Invasions.
Living Oceans is calling on Minister of Fisheries and Oceans Gail Shea
to stop approving new net-cage salmon farms until she can provide the
public with clear evidence that Canada’s rivers are not being colonized
by invasive species.
The study, Occupancy
dynamics of escaped farmed Atlantic salmon in Canadian Pacific coastal
salmon streams: implications for sustained invasions, cited
previous research indicating that the number of escaped fish reported by
the B.C. salmon farming industry is greatly underestimated.
“There is simply no way to verify the industry’s data,” said Will
Soltau, Salmon Farming Campaign Manager for Living Oceans. “Salmon
farmers self-report escapes and at the same time, Fisheries and Oceans
Canada (DFO) does not publicly share data from the Atlantic Salmon Watch
Program it operates to receive reports from fishermen, field
researchers and hatchery workers.”
And, in fact, escaped fish are common around the world from fish farms. Earlier posts on this site note that it is roughly, if you can believe it, 4M escapes in Chile per year, 1M in Norway, etc. And in-stream problems have occurred in Scotland, Ireland, and in Atlantic Canada, so if the industry is not forthcoming, and honest, and every river within 300 km of a fish farm in Atlantic Canada has farmed Atlantics in it, why should they be believed in BC? Or anywhere else?
And Living Oceans does report an unreported escape event in Atlantic Canada, again the issue being the fish farms being dishonest, as they are required to report escapes. They can't just rape the ocean. Here is a quote from LO: "The significant number of escapees indicates that a large escape in the
Bay of Fundy had gone unreported by the salmon farming industry."
Here is another paper on escapes in BC, WA and AL: https://www.researchgate.net/publication/255978051_A_biological_risk_assessment_for_an_Atlantic_salmon_Salmo_salar_invasion_in_Alaskan_waters.
There are many more papers.
And DFO is part of the problem. This from LO: "“When salmon farming was introduced in Canada, fishermen and
environmentalists protested that fish escaping from the net-cages posed a
threat to wild stock,” said Soltau. “First DFO said escaped Atlantics
couldn’t survive. Then they said they wouldn’t enter river systems. Then
they said they wouldn’t spawn, but they found feral juveniles. Since
then, DFO has done nothing to ease public concerns about escaped farmed
Atlantics’ impact on wild salmon in Canadian rivers.”"