March 15, 2011

Poached Salmon, a fish story

As often happens when investigating global warming claims, you begin down one path of inquiry only to be diverted to others and then you happen upon something that just totally changes your whole outlook on the original subject matter.

Being originally from the Pacific Northwest and having a fondness for salmon I actually had it for dinner tonight, yum.  I was much intrigued when I came upon this story:

Rising temperature in Fraser River affecting Salmon population

Oh no I lamented, now the CYBER WAG (computer generated Wild Ass Guess) is coming for my salmon! But it is worse than that, it is not only that the modelers are projecting the demise of my fishy friends, they claim global warming is already in the process of killing them off.

From the Globe and Mail story:
The Fraser River is heating up because of climate change and an increasing number of salmon are dying in the warmer water from diseases or parasites or are simply dropping dead from cardiac collapse, a federal judicial inquiry has been told.

Scott Hinch, an expert witness on aquatic ecology, told the Commission of Inquiry Into the Decline of Sockeye Salmon in the Fraser River that sometimes 50 per cent of the salmon that return to the river die before they reach the spawning beds.

Dr. Hinch said because the Fraser has increased in temperature by about 2 degrees C, salmon are changing the timing of their spawning migrations, to enter rivers weeks earlier or later, in an effort to avoid warm water. And once in the river they are seeking out cold-water refuges, sometimes going up tributaries to sink to the bottoms of lakes or schooling where cold streams enter the Fraser.

Trying to research this a bit deeper I came to see that the amazing Dr. Hinch has a nice little cottage industry devoted to this theory, but that is for others to dig into, my concern is only for the salmon.

What first pricked my always active curiosity when it comes to such claims was that 2 degrees C warming of a snow pack fed river system. Where did they get this number and how did they determine it was the result of global warming. I spent literally minutes of Google searching for the source of this claim and as often happens I came face to face with pay walls and other assorted devices of academic and scientific opacity.

But after some further digging I believe I have come across the study behind the hyperbole about the Fraser River temperature increase. It seems this is the primary source  "Simulations and retrospective analyses of fraser watershed flows and temperatures"  :

ABSTRACT In order to provide better estimates of the thermal-induced stress encountered by salmon migrating to their spawning grounds, a model is used to hindcast temperatures throughout the mainstem Fraser and Thompson Rivers back to 1953. Tributary and headwater temperatures that are not available prior to 1993 are estimated with both linear regression and neural network techniques. The average root mean square difference between model temperatures and those observed at Hell’s Gate, on the lower Fraser River, is computed to be1.12°C.Historical flow and temperature observations are also used to establish patterns and trends for the Fraser River watershed. The Julian day numbers by which one-third and one-half of the integrated yearly discharge had occurred were computed and found to be progressing earlier at the rates of 0.11 and 0.09 days per year, respectively. Both values are significant at the 95% level. Average summer Hell’s Gate temperatures from 1941 to 1998 are warming at the rate of 0.012°C per year, though the relatively large standard error of 0.008°C means that this result is not significantly different from zero at the 95% level. However, when the analysis is restricted to1953 to 1998, the trend becomes 0.022°C per year and the significance level rises to 98%. An analysis of the 1953–98 atmosphere-to-river heat exchange at Kamloops and Prince George produces positive increases of 0.52 W m–2 per year and 0.90 W m–2 per year, respectively. When these trends are used to force the river temperature model, they explain approximately 35% of the 1953–98 temperature increase at Hell’s Gate. An additional 20% is explained by related increases in the headwater and tributary temperatures. Though these estimates have considerable statistical uncertainty, they nevertheless suggest that most of the river warming can be attributed to climatic effects.

Flow rates and river temperatures are also shown to exhibit significant differences in the summers following El Niño and La Niña winters. On average, during the summers following El Niño events, flows are approximately 800 m3 s–1 smaller and river temperatures are approximately 0.9°C higher on the lower Fraser River. Similar estimates are produced for the major tributaries and headwaters of the Fraser and Thompson Rivers. The implications for future salmon recruitment are briefly discussed.

Putting aside for the moment the fact that they used actual data from Hells Gate to hindcast (model) their findings. The actual findings were "1941–98 temperature observations at Hell’s Gate suggested a warming trend of 0.012°C per year", which if continued would mean a 1.2 deg C per century. Since this did not satisfy them for some reason, possibly perceived corrupted data prior to 1953 , they chose to pick the 1953-1998 data which gave them a .022 deg, C per year or a 2.2 deg C per century trend.

Far be it from me to question all this scientific work, my only concern is the salmon. But I will point out that it has only been 70 years since 1941 and 58 years since 1953. This being the case and if the actual temperature trend line is correct and has remained consistent since 1998 then as of 2011 the temperature increase of the Fraser River at Hells Gate would have risen .084 deg C or 1.276 deg C since 1953.

Since this temperature increase obviously did not meet the criteria, they felt it necessary to "force the river temperature model" by splicing in data from other locations to get the desired results. Or at least that is what it seems to me. They then fired up there always handy models to hindcast the past, which gave them a warming trend that is not actually the temperatures recorded on the river but what their models say it was, got it?

Throughout the study itself you find little caveats like this:(emphasis mine)
It should also be mentioned that several simple significance tests are carried out in the following presentation. Most of these rely on an underlying assumption of normality for the relevant statistic. Though no attempt is made to verify this assumption, we note that for samples of size greater than thirty, the distributions of many statistics (e.g., mean) are approximately normal
In order to estimate the tributary and headwater temperatures in years when there were no observations, two different approaches were used to quantify relationships with measured flows and weather
In both cases, we note that these data may be providing biased estimates of the atmosphere-to-river heat exchange because they were collected at airports rather than directly above the relevant rivers. Nevertheless, as they are the only data available, there is no way to compensate.

I guess this is why they say "these estimates have considerable statistical uncertainty". Yet it appears it is these uncertain estimates that are being used to feed a supposed salmon slaughter on the Fraser River.

And that is the important point that changes everything.

You see it really does not matter if the river heated up whether in reality or just in the mathematical gyrations of these scientist. What matters is the dieing salmon in the river. The whole point of this exercise was to show that global warming had warmed the Fraser River  (ridiculous) and this warming was killing off the salmon, remember?

"The Fraser River is heating up because of climate change and an increasing number of salmon are dying in the warmer water from diseases or parasites or are simply dropping dead from cardiac collapse..."
Well in my searching I came across a report by a Canadian Government committee done in 2004 when these same concerns were put forward . The report apropriately was titled " HERE WE GO AGAIN...OR THE 2004 FRASER RIVER SALMON FISHERY"  although they do consider the possibility that higher water temperatures in 2004 could have been a contributing factor in lower fish counts they also make this very obvious observation:
(emphasis in original)
Record-high temperatures in the Fraser River was the initial reason provided by DFO to explain the discrepancy between the number of fish that were counted on the spawning grounds and the number of fish that were reported in the River. At one point in August, water temperature was four degrees higher than normal, well above the reported optimum temperature for successful migration; however, by that time, Early Summer-runs would have already reached the spawning grounds.

The hypothesis is that, coupled with increased fishing pressure or increased harassment, and ensuing susceptibility to diseases, the unusually high temperatures in the Fraser River caused the fish to run out of energy resources before they could reach the spawning grounds. However, numerous witnesses told the Committee that they had serious reservations about this explanation because there was no evidence of a massive fish kill.
In other words where are the dead fish? Not only should the fish have been to their spawning grounds well before they were poached by the late summer heat, they did not die in the river.  They asked an expert for his input which you can read in the study, but here is a pertinent paragraph (emphasis mine)

Dr. Farrell emphasized that different sockeye salmon stocks faced different temperatures during their migration, and that there were differences in terms of temperature tolerance, disease susceptibility, and exercise performance for different stocks. It is therefore possible that while temperatures in early July were significantly lower than in late July or August, Early Stuart salmon still experienced temperatures that were near the all-time highs for this timing group and therefore they might have been affected as much as later runs. Dr. Farrell pointed out that there were important knowledge gaps in this area mainly because the specific studies that needed to be done to address this question had not been done. The witness added that in order to establish definitively the role of river temperature on the migration of sockeye salmon, the appropriate studies will have to be performed.

Well those studies are sure being performed now aren't they? But at the time the committee was not convinced:
The Committee was also interested by the lack of clear evidence of a massive kill of sockeye salmon on the Fraser River. Dr. Farrell indicated that dead adult sockeye salmon are not always visible. His group observed that carcasses often disappeared, that dead fish did not necessarily float immediately or could remain in the depths of some of the Fraser River watershed lakes, and that dead fish could become food for other fish such as sturgeon. The Committee doubts though that these explanations would account for the absence of 1.6 million sockeye carcasses. 
It is rather difficult to hide a million and a half dead fish and we are not talking sardines here, though Dr Farrell did give it his best shot. Which brings us to today, where are the dead fish cluttering the snow fed boiling Fraser River? (emphasis mine)

Once-in-a-century salmon run hits Canada's West Coast

(Reuters) - Every year Vancouver resident Stephen Ottridge takes hamburgers or steak to his street's annual summer block party.

This year, against the backdrop of what looks to be the biggest sockeye salmon run in almost a century in the nearby Fraser River, he arrived with a salmon large enough to fill the whole barbecue.

"There is a cornucopia of salmon this year, so we decided to treat the block to some," Ottridge said from the city on Canada's Pacific Coast, where marine experts are both puzzled and delighted by the unexpected glut of the bright-red, succulent fish.

After years of declining sockeye numbers and a struggling fishing industry, the Pacific Salmon Commission last week said it now expects 25 million sockeye will return to the Fraser River this year -- more than double its earlier forecast and the best run since 1913.

Last year, slightly more than a measly 1 million sockeye made their way back to their spawning grounds, prompting the Canadian government to close the river to commercial and recreational sockeye fishing for the third straight year.

The reasons for the salmon bonanza remain a mystery, but what has helped is that it has coincided with a "dominant-run" year, said Carl Walters, a fisheries expert at the University of British Columbia's zoology department.

"Every fourth year is the dominant year when the biggest run comes in. The year after that is sub-dominant. Then you get two really low runs," Walters told Reuters.

Twenty years of declining sockeye in the Fraser River led the Canadian government to launch an investigation last year into the disappearance of the fish at a time when numerous theories abound.

These include that climate change may be reducing food supply for salmon in the ocean, and that rising temperatures in the river may have weakened the fish.

Commercial fish farms that the young Fraser River salmon pass en route to the ocean have also been blamed for infecting them with damaging sea lice, a marine parasite.

While consumers are enjoying cheap salmon for the first time in years -- prices for fresh sockeye are down about 30 percent from a year ago -- the fishing industry is struggling to cope with the sudden bounty.

"It is an amazing thing but the problem is that this has come along when the market has been lost. Now we have all this fish and we can't do a lot with it," said Bob Fraumeni, owner of FAS Seafood Producers, which operates a West Coast commercial fishing fleet and retail outlets.

There are reports of fish rotting on boats as fishermen run out of ice and freezer space, and of tempers flaring as boats jostle for space on the water.

For now though, most are enjoying the bumper harvest.
"I've been in the business for 20 years and I've eaten sockeye from everywhere and this is, in my opinion, the best-tasting Canadian sockeye around," said George Heras, president of family-owned Seven Seas Fish Market in Vancouver.
Smoked Salmon anyone?

1 comment:

  1. I'd like to secret a dead fish into Dr. Hinch's mailbox.