TOPIC:

www.nps.gov/yell/learn/nature/lake-trout.htm

www.nps.gov/yell/planyourvisit/upload/introduced_fishes.pdf

There was a documentary on this i saw last year. Maybe natl geographic channel. It was about the declining elk herds, and they pinned the cause on the demise of the cutthroats due to laker invasion.
Less cutthroat for the bears to eat in the spring shifted their need for food to elk calves. Very interesting story

There could be a bit of revisionist history here - sort of like the Indiana DNR's "official" recollection of how Indiana's deer herd went from zero to statewide in a relatively short time frame. That's another story.

I became obsessed with Great Lakes fishing back when the first cohos showed up here in Indiana and that interest included lake trout. I remember readingaccounts of the demise of the lake trout and ongoing subsequent efforts to re establish them through lamprey suppression and stocking. No one knew back then it was their diet of alewives suppressing natural reproduction. All the fish guys knew was they were stocking millions, the fish were growing to maturity and no wild babies were being made.

Since lakers don't mature until they are 6 or 8 years old, it wasn't as though any project to evaluate reproduction was quick. Dump in a baby trout in 1955 and the result of that effort couldn't be assessed for nearly a decade. Through the 60s, 70s, 80s etc, many theories were advanced and projects acted upon to see what could be done to get the natural reproduction back on track.

One theory was the brood stock wasn't coming from "Lake Michigan" strain trout. Initial efforts were made with laker parents obtained from who knows where. That failed. So they got trout from Lake Superior to get the "Great Lakes" genes. There were no lower lake fish left to propagate. That didn't work. So they started looking for lakes where Lake Michigan fish may have been transplanted so they could get some of them, spawn them and put that genetic strain back in Lake Michigan.

I'm not sure of the years, but this was probably in the 80s or so. Two sources of Lake Michigan strain fish were found - Green Lake, Wisconsin and Yellowstone Lake.

Remember, 40 or 50 years ago (and longer) the "naturalist movement" wasn't imbedded in the psychie of fish scientists. Rainbow trout were stocked in brook trout streams, brown trout were hauled in Europe, carp were brought from Asia, Zander from northern Europe were planted in the upper Midwest. Stripers from the east coast went into TVA lakes. Some of these were success, some failures, some disasters with unintended consequences. All or many were done by government fisheries agencies, not illegal stockings by wannabe fish managers.

This is why the story above doesn't ring so true. I've no doubt lakers in Yellowstone Lake are nasty and upsetting the "natural" balance. But I question the time table and origin of the trout as reported in the story.

Fake news?

BNature wrote:

There could be a bit of revisionist history here
I'm not sure of the years, but this was probably in the 80s or so. Two sources of Lake Michigan strain fish were found - Green Lake, Wisconsin and Yellowstone Lake.

This is why the story above doesn't ring so true. I've no doubt lakers in Yellowstone Lake are nasty and upsetting the "natural" balance. But I question the time table and origin of the trout as reported in the story.

Fake news?

Not fake news at all, just imprecise terminology causing you some confusion. "Yellowstone Lake" does not equal "Yellowstone" in the colloquial sense - most people use "Yellowstone" to refer to the entire park.

Here's the full details to understand why Ed's links are correct:

In 1890, some of the first fish brought to Yellowstone were lake trout from Lake Michigan, which were stocked in Lewis and Shoshone lakes in the upper Snake River drainage (Varley 1980). Over time, the lake trout dispersed downstream, invading Heart and Jackson lakes and establishing sizable populations. Lake trout were present in Yellowstone for more than a century before they were found in Yellowstone Lake, where one was caught by an angler in 1994 (Kaeding et al. 1996).

The lake trout that Lake Michigan managers went and got to obtain Lake Michigan genetics were from Lewis Lake in Yellowstone Park - NOT Yellowstone Lake

You can see it if you peruse the GLFC stocking database, which lists strains such as Green Lake (as you mentioned), and Lewis Lake, which are the fish in question here.

reel wrote:

There was a documentary on this i saw last year. Maybe natl geographic channel. It was about the declining elk herds, and they pinned the cause on the demise of the cutthroats due to laker invasion.
Less cutthroat for the bears to eat in the spring shifted their need for food to elk calves. Very interesting story

That's a great example of how cascading effects in the ecosystem are not easy to anticipate or manage, and why invasive species are so disruptive, particularly in aquatic systems that have multiple components, such as species that utilize both large lake and river habitats