Originally posted by: L.M. Ray on 2/7/2006 12:15:08 PM
NEW: SOS for alewives!
Mark Lamb -- Mon, Jan/23/06
By James Janega
Tribune staff reporter
Published January 22, 2006
With a series of new studies confirming the worst, Lake Michigan fishery managers have begun a drastic plan to save the fish species whose absence they believe would crash the lake's ecosystem.
There was a time when Lake Michigan was stuffed to the gills with the Atlantic invader, which washed up on beaches by the smelly ton. As strange as it may sound, fishery managers now fear a downturn last year has left the lake with too few.
Biologists blame the change on the Chinook salmon of the Pacific Northwest. The most voracious fish in the lake. The fish that feeds in the same water level as alewives. The very fish they've stocked since 1967 to hold the alewives in check.
Alarmed their decades-long plan may suddenly be working too well and believing the Chinook have taken to breeding on their own, fishery managers said they'll stock 1 million fewer in their annual release this spring.
"The system is compensating at such a quick rate," said research biologist Randy Claramunt of the Michigan Department of Natural Resources, "and not in a way that we particularly want it to."
Much about life in the lakes is a mystery, fishery experts said. And though neither the alewife nor Chinook is native to Lake Michigan, their presence represents its new reality, in which stocked fish are pitted against invasive species to battle in the fish tank that was once a vibrant Great Lake.
At the heart of this new ecosystem is the Chinook salmon.
A $4 billion commercial and sport fishery has grown up around the Chinook and other big fish that eat alewives.
So the alewife must be saved.
It's arresting to realize, when you really grasp it, that most fish in our inland sea aren't from here and that nobody fully understands how they interact with one another.
Lake Michigan once had a food chain so simple a 5th-grader might draw it. (Lake trout eat forage fish that eat tiny things that eat plankton.)
Ecologists said the lake's ecosystem has morphed into a complex web involving a dizzying cast of scaly immigrants, natives of waters from Latvia to Afghanistan, plus a smattering of game fish from elsewhere brought in for good measure.
Among the relative newcomers are Chinook and Coho salmon and brown and rainbow trout.
The trout were introduced first for sport fishing in the late-1800s. The Coho and Chinook were bred with hopes of curbing alewives, and the Chinook at least fulfilled fish managers' wildest dreams.
Local fish--trout, chubs, whitefish and the like--have been reduced to despairing lives in far-flung pockets of the lake, perhaps to be rehabilitated later, maybe.
But the alewives and Chinook are fighting terrifically to stay.
The alewives came first, blundering up the St. Lawrence River in the 1940s. Their only plausible native threat on arrival were lake trout, big, ancient, deepwater fish, which by then were dying off thanks to invading lampreys and a thiamin deficiency.
Natives of Newfoundland, the alewives since their arrival have wandered the lake in great shimmering assemblies, looking for a smidgen to eat and settling in comfortably. Grasping opportunity in their troutless new world, they multiplied, overate and then themselves died--in shocking abundance and all over pricey lakefront real estate.
Keen to control this, fish managers started pouring in Chinook, reasoning they might provide a few nice days of fishing in a lake that only years earlier had been a wasteland of lampreys.
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