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Just watched the news on the Sockeye deaths on the Harrison River. Fisheries biologists think that these fish were poisoned by chlorine. All the dead fish were still fresh and silver and should not have died.
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Did the guy actually say he was a biologist? I didn't see if BCTV identifed the guy. He seemed a lot too confident in his off the cuff acnecdotal conslusion to be a responsible biologist. Don't believe all of what you hear.
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No, the guy that was interviewed was a guide. He came across as experienced (probably is), and his point was that there were no other evident problems. Chlorine may not be the cause, but it sure looked like "sudden and accidental" ... rather than disease. As if we don't have enough problems on the Fraser ...
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I was fishing on the Harrison on Saturday and saw all the sockeye floating by some looked like they just died. Seem to be coming from the Chehalis river mouth area.
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There is probably a lot of organic material burried in the sediments at the mouth of the Chehelis. Does anyone remember a couple of years back when the Chehelis blew out just below the hatchery and went through the forest- All that wood and soil had to go somewhere- it is probably burried in pockets out on the floodplain near the mouth of the Chehelis. Anoxic (without oxygen)sediments are known to produce copious quantities of sulpher dioxide (very toxic to fish) in addition to stripping oxygen out of overlying waters (Biological Oxygen demand or BOD). The warmer the water, the less oxygen it has to start with and the higher the BOD. This spring that whole area was flooded probably allowing the organic stuff on the bottom to rot more than usual, perhaps causing these fish kills, (note that it has been hot the last week or two). If a school of sockeye wandered into that some bad water or it got mixed into the Harrison, then a fish kill could result. As for the guide, I am sure he meant well, but he was little overconfident in his explanation (ie. where upstream of the kill would this point source have been). The fact the sockeye carcases were clean and fresh would indicate that the problem was environmental, and the fish died quickly- just the sort of thing you might see if the fish were poisoned with swamp gas or lack of oxygen. These sort of events have contributed to fish kills in other places before.
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Cory, I was there with John Higgy on Saturday. While a Sulpher Dioxide or BOD overload in the Harrison may be a possibility, wouldn't it affect the smaller salmonids as well? We saw large numbers of schooling fingerlings (cutthroat?) in the same section of the river that did not seem to be stressed. We didn't do any measurements, but water temperatures did not seem abnormally high (some of the natives who were gill netting near us in shorts were complaining of the coolness of the water)
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Numbers of dead Sockeye have been common on the Harrison over the last few years. The same is true for springs and chum - though not in the same numbers. The Harrison is typically much warmer than the Fraser - after all it is sourced in a lake and clear - much more heat absorbtion. Temperatures over 60 F increase sockeye mortality. They are a cold water fish. Consider too the shear number of sockeye now running up the Harrison with resulting from the restrictions of commercial fishing of the last few years - I've heard the Weaver Creek run numbers up to several hundred thousand. Mortality among all Pacific Salmon is a fact of life - some don't have the jiuce or the bio clock to make it to spawning - with that number of fish - a small % of mortality can put a lot of dead fish in the water. BTW most freshly dead fish sink - floating fish are usually rotten - this fills their bellies with gas - so they float.
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