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Michigan/Great Lakes record Chinook last year Nov 17, 2022 4:14 am #36060

  • BNature
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Exactly, the triploid program started in 1988 was hoped to produce a few giant kings by sterilizing them so they would live several years longer than fertile fish. The plan was not to fill the lake with giant king salmon, but to have a few brutes out there for angler to stumble across from time to time. From what I recall, the triploid project was discontinued mostly because it coincided with the advent of the bacterial kidney disease that was wiping out hundreds of thousands of king salmon and there was no vaccine available. I think they were stocked by both Michigan and Wisconsin for only a couple years.  Most of the triploids probably got BKD and died young along with their fertile cousins. As I recall, the scourge of BKD was quelled mostly by selective breeding. When the potential parent fish were caught at the weir, they were physically examined before stripping their eggs or milt to produce the next generation of fish. Evidently there are physical clues that identify infected fish from non-infected fish. The ones not infected became the breeders and over a relatively short period of time - just several years - most of the salmon are now somewhat BKD resistant. At least I don't recall anything about present day egg gatherers now checking the fish they strip for BKD.  
Also, by the time BKD was defeated, zebra mussels were rapidly expanding and the alewife numbers were dropping precipitously. With baitfish populations dwindling, it made no sense to stock even a relatively few extra-long lived salmon in the lake that would put additional pressure on the lake's prey fish populations. 
Also, by this time the "naturalists" in the ranks of Great Lakes States natural resource agencies were gaining traction and objecting (as best they could) to continued stocking of  invasive species - salmon and steelhead - into the Great Lakes even though these programs were started due to the ecological havoc created by an invasive species (alewife) completely disrupting the ecology of Lakes Michigan, Huron and Ontario. Factor in declining budgets, Dr. Tanner's retirement from the Michigan DNR and the triploid program was only a blip in history.  
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Michigan/Great Lakes record Chinook last year Nov 17, 2022 9:20 am #36061

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Ben:  Do you think there's a possible genetic component to delayed spawning?  For instance, the Kenai River in Alaska and the Campbell River in BC routinely produce extra-ordinary sized kings and from what I've been lead to believe it's because the strains that are native to these stream routinely (genetically?) live to be 5+ or 6+ years of age and the genetics haven't been diluted much extent by hatchery fish.  My point, I guess is that while the eggs used by Michigan and Indiana for the hatcheries are a mixed-genetics from 2+ and 3+ aged parents. No one knows where the Michigan record fish was born and how many generations away from its hatchery-spawned ancestors.  


Yes, absolutely. There are a lot of sub-populations of chinooks out west in their native range, and they have different lifespans, there are spring chinook, fall chinook, etc. Lots of genetic diversity. 

To the best of my knowledge, all chinook that were sourced for Lake Michigan were from a single population, so we wouldn't expect to have all of the genetic diversity and different lifespans, run timings, etc that are seen on the west coast. On an evolutionary timescale, there haven't been that many generations in the great lakes to expect too much diversity to spontaneously happen, particularly when its extremely reliant on hatchery production

Probably the best example of high selective pressure applied to chinooks is the closing of the Little Manistee Weir in mid-August, so if any wild fish want to succesfully reproduce, they have to get upstream before then. Over time it's created an earlier run timing of wild fish there, in July/early August in many years
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