A disturbingly flawed piece of pseudoscience was recently sent out to fishing guide associations all over B.C.
Alexandra Morton and other anti-salmon farming activists are fixated on one explanation for why salmon returns have declined since the 1980s.
They say that since the late 1980s and early 199os, salmon have declined.
That’s because, they say, it was in that same time period when salmon farming in B.C. experienced its largest growth period.
Therefore, salmon farms MUST be responsible for the decline in productivity.
While this makes for an alarming-looking graph, what is even more alarming is the bad science behind it.
Once again, correlation does not equal causation.
But even more important, Ms. Morton, who has stated she has spend “thousands of hours” reading through all the documents submitted to the Cohen Commission, has very obviously ignored many documents submitted to the Cohen Commission which disagree with her hypothesis.
Six scientists who also reviewed all the data submitted to the commission were tasked by Justice Cohen to synthesize it all into a report. Their work, “Fraser River sockeye salmon: data synthesis and cumulative impacts,” has been largely ignored but includes some fascinating information which shows how bad Ms. Morton’s science really is. Lets begin by looking at their premise.
The Pattern We Seek To Explain
Based on the Cohen Commission’s technical reports (Peterman and Dorner 2011, Hinch and Martins 2011), we can describe five key attributes of change in Fraser and non-Fraser sockeye populations:
1. Within the Fraser watershed, 17 of 19 sockeye stocks have shown declines in productivity over the last two decades (the two exceptions are Harrison and Late Shuswap sockeye).
Hold on. According to Ms. Morton’s bad science linked above, only the Harrison River runs have not shown declines. She never mentions Late Shuswap runs. Why is that? Because they don’t fit into her neat and tidy theory that the only salmon unaffected by the decline are the ones which didn’t have to swim past salmon farms.
2. Most of 45 non-Fraser sockeye stocks that were examined show a similar recent decrease in productivity. Thus, declining productivity has occurred over a much larger area than just the Fraser River system and is not unique to it.
This has also been ignored. As we’ve said before, stocks have declined since the 1980s from Alaska to Washington, including in regions where there are no salmon farms for thousands of miles. This does not fit into her tidy theory either.
3. Of the nine Fraser sockeye stocks with data on juvenile abundance, only Gates sockeye have showed declines in juvenile productivity (i.e., from spawners to juveniles) but 7 of the 9 stocks showed consistent reductions in post-juvenile productivity (i.e., from juveniles to returning adult recruits).
Morton is not noting this either, and lumping all productivity statistics together.
4. There have been three separate phases of decline in productivity since 1950. The first started in the 1970s, the second in the mid-1980s, and then the most recent one in the late 1990s or early 2000s, with individual stocks showing these trends to various extents.
On Ms. Morton’s graph, a decline in productivity is apparent in the 1960s, similar to the decline in the 1990s. What is her explanation for that decline? Can that be blamed on salmon farms too, which did not exist anywhere in the world at that time?
5. Over the last two decades there has been an increasing amount of en-route mortality of returning Fraser sockeye spawners (i.e., mortality between the Mission enumeration site and the spawning ground). This results in reduced harvest, as fishery managers do their best to ensure enough spawners return to the spawning ground in spite of considerable mortality along the way.
What is different here compared to previous declines in productivity? More returning fish have been dying between Mission and their spawning grounds. There are many possible explanations for why this might be happening.
And that is exactly what the Cohen Commission was formed to find out.
The synthesis of the data by the six scientists results in conclusions much different that Morton’s synthesis of cherry-picked data supporting her pre-conceived hypothesis. They recommend more study, particularly in the Strait of Georgia, but also offer conclusions by the Pacific Salmon Commission, which found that it was most likely marine ecology inside and outside Georgia Strait as well as climate change had the greatest impacts on salmon returns (see the last two pages of the synthesis report).
What’s the take-home message here?
Salmon science is complicated. It does no one any good, particularly the fish, for one person who hates salmon farming to make simplistic graphs and conclusions and send them out to fishing guides.
There’s a word for that. It’s called “propaganda.”