Long before the walleye was officially royalty on Lake Erie, the Great Lakes had a real king. He was strong and brilliant and tough and clearly in charge, residing at the top of the food chain.
The lake trout was the big kahuna. Although also native to Lake Erie, lake trout were most prevalent in the deeper, colder lakes - Michigan, Huron, Ontario and Superior.
Commercial fishing for lake trout was a booming business around 1940, with more than 7 million pounds a year harvested from Superior, Michigan and Huron.
Lake trout were the preferred table fare for many who lived near the lakes, and were packed in ice and shipped to markets on the East Coast.
But by 1952, the commercial harvest in Huron and Michigan was down to zero. We got a lesson in the perils of uninvited guests, as lake trout got hit by a nasty double whammy.
First came the sea lampreys, an aquatic vertebrate that is native to the Atlantic Ocean but has the ability to live in both salt and fresh water. It is a primitive creature with no jaws, only a suction-cup mouth rimmed with sharp teeth.
They attach to the side of a lake trout, drill through the skin, then feed on the blood, usually killing the lake trout.
Lampreys are believed to have reached Lake Ontario through the St. Lawrence Seaway, but Niagara Falls kept them from moving further.
They eventually entered the other Great Lakes through the man-made Welland Canal.
They marched onward, and were found in Lake Erie in 1921, Lake Michigan in 1936, and Lake Huron in 1937.
The lamprey took a liking to lake trout as a host, and the population of lake trout took a big hit. There are graphic photos of sickly looking lake trout caught in nets, with several lampreys attached to their bodies, like foot-and-a-half long leeches.
At the same time over-fishing was becoming a serious problem, and a third assault was making life even tougher for the lake trout.
The alewife, a species of herring, made its way into the Great Lakes using the same Welland Canal as its passageway. Their numbers exploded and soon lake trout were feeding heavily on the invasive alewives.
But the alewives were not nearly as nutritious as the native species the lake trout had traditionally used for food, and the lake trout developed vitamin deficiencies that produced a very high mortality rate in their young. Poor reproduction, death by lamprey and over-fishing knocked the lake trout off its Great Lakes pedestal.
For a while, lake trout were thought to have disappeared from some of the Great Lakes. An aggressive stocking and restoration effort has had some success, but only Lake Superior is able to maintain a stable population.
Lake trout belong here. They are native only to the northern part of North America, and it was nature that put them at the pinnacle of the Great Lakes food chain.
It was a series of missteps by man that put them in peril. That Welland Canal we used to ease shipping obviously had other unintended consequences.
That messy story presents us with a vivid lesson as the Asian carp crisis boils on the canal connecting Lake Michigan with the Mississippi River system. If they get in, the carp have the potential to be the most devastating invader yet.
Let's not be so quick to dismiss the possibility. The lake trout saga demonstrates that once invasive species get in the Great Lakes, you can fight, but you never win. The invaders are nothing if not resilient. Some huge dominoes start to fall, and we have nothing in our toolbox to control their impact.
Matt Markey is the A-T outdoors columnist.
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