Aliens of the Great Lakes

Published 9:24 am Thursday, March 25, 2004

By Staff
In pondering on what to write about this week for some reason my mind kept going to the Great Lakes. Maybe it's a subconscious thing, longing for summer and the beach.
As I mulled over the Great Lakes' many inhabitants I began to realize just how much man has altered the denizens of our treasured lakes. Some has been by design, some by accident. Some has been good, much has been detrimental. For better or worse, it sure is a different place today.
One hundred fifty years ago the fish life in the Great Lakes was relatively mundane. About the only species in great abundance were perch, lake trout, suckers, whitefish, herring and chubs. In some locales, particularly the northern portions, smallmouth bass, pike, muskies, walleye and a few brook trout provided limited action for anglers. There were also some sturgeon, sheephead and burbot cruising about. That was pretty much it.
With such a large playground man couldn't resist trying his hand at remodeling. The first successful introduction of an alien species into the Great Lakes came in 1890 when Wisconsin planted some German brown trout. Shortly thereafter, in 1893, carp from Asia were also planted, unfortunately with outstanding success. Atlantic salmon were native to Lake Ontario but not the others. For more than a hundred years uncountable attempts to introduce Atlantics into all the Lakes failed. It wasn't until Lake Superior State University began planting a strain of landlocked Atlantic salmon from Sweden that Atlantics joined the permanent roster of Great Lakes sport fish. Throughout the 1900s steelhead trout from the west coast were also routinely dumped into the Great Lakes, though their numbers remained minimal until recent mass planting programs.
In the early 1900s smelt, an ocean fish, were introduced into some of Michigan's inland lakes as food for planted Atlantic salmon. They immediately made their way into the Great Lakes and rapidly expanded. Smelt netting was a major event until they declined severely in the 1980s. The cause for the decline is unknown and they remain at low levels today.
To this point man's tampering was fairly benign but in 1932 came the Welland Canal which circumvented Niagara Falls and opened passage between Lakes Ontario and Erie. Now there was unfettered access to the Great Lakes from the St. Lawrence Seaway, thus the Atlantic Ocean. One of the first invaders through the Canal was the dreaded sea lamprey. By 1950 these eels literally ruled the Great Lakes, sucking the life blood from lake trout and nearly pushing them into extinction. Today lampreys are controlled with electrical weirs and a chemical that kills lamprey larvae in their spawning streams, however, it is expensive and labor intensive. There are also fears the lampreys may develop immunity to the chemical.
Alewives also came through the Welland Canal in huge numbers. When lampreys killed off the predator fish alewife numbers exploded. They compete directly with yellow perch, whitefish and others for food causing noticeable decline. White perch, native to the New England states, also came up through the Canal to compete with Great Lakes fish.
In 1966 the Great Lakes were forever changed by the planting of Pacific salmon, first coho, then Chinooks. Today, intensive annual planting of salmon, steelhead and lake trout make our Lakes a fisherman's dream.
The latest avenue of alien invasion is via ship. Starting in the mid 1980s European and Asian minnows such as goby and ruffe and invertebrates such as zebra mussels have been showing up, apparently purged from the ballast tanks of foreign vessels. These aggressive species are now prevalent and competing with Great Lakes natives like perch and whitefish for food and spawning grounds. Zebra mussels are severely altering algae growth.
Obviously, some of these introductions have been beneficial while others pose serious threats to the ecosystem, many that have yet to be fully realized.
I guess we could sum up all these aliens as "The Good, The Bad and The Ugly." Carpe diem.
Larry Lyons writes a weekly column for Leader Publications. Email him at