The Ten Threats to the Great Lakes” is looking first at alien invasive species. There are more than 160 non-native species in the Great Lakes basin. If they do environmental or economic harm, they’re called invasive species. There are estimates that invasive species cost the region billions of dollars a year. Different species got here different ways. David Sommerstein tells us how some of the region’s earliest invaders got into the Lakes:
We’re bringing you an extensive series on Ten Threats to the Great Lakes. The Great Lakes Radio Consortium’s Lester Graham is guiding us through the reports:
“The Ten Threats to the Great Lakes” is looking first at alien invasive species. There are more than 160 non-native species in the Great Lakes basin. If they do environmental or economic harm, they’re called invasive species. There are estimates that invasive species cost the region billions of dollars a year. Different species got here different ways. David Sommerstein tells us how some of the region’s earliest invaders got into the Lakes:
If the history of invasive species were a movie, it would open like this:
(Sound of banjo)
It’s 1825. Politicians have just ridden the first ship across the newly dug Erie Canal from Buffalo to New York.
(Sound of “The Erie Canal”)
“I’ve got an old mule, and her name is Sal. Fifteen miles on the Erie Canal…”
Chuck O’Neill is an invasive species expert with New York Sea Grant.
“At the canal’s formal opening, Governor DeWitt Clinton dumped a cask of Lake Erie water; he dumped that water into New York Harbor.”
Meanwhile, in Buffalo, a cask of Hudson River water was triumphantly poured into Lake Erie.
“In a movie, that would be the flashback with the impending doom-type music in the background.”
(Sound of ominous music)
It was an engineering and economic milestone, but a danger lurked. For the first time since glaciers carved the landscape twelve thousand years ago, water from the Hudson and water from the Great Lakes mixed.
(Sound of “Dragnet” theme)
Enter the villain: the sea lamprey. It’s a slimy, snake-like parasite in the Atlantic Ocean. It sucks the blood of host fish.
Within a decade after the Erie Canal and its network of feeders opened, the sea lamprey uses the waterways to swim into Lake Ontario. By the 1920’s and 30’s, it squirms into the upper Lakes, bypassing Niagara Falls through the Welland Canal.
What happens next is among the most notorious examples of damage done by an invasive species in the Great Lakes. By the 1950’s, the sea lamprey devastates Lake trout populations in Lake Superior. Mark Gaden is with the Great Lakes Fishery Commission.
“They changed a way of life in the Great Lakes basin, the lampreys. They preyed directly on fish, they drove commercial fisheries out of business, the communities in the areas that were built around the fisheries were impacted severely.”
The sea lamprey wasn’t the only invader that used the canals. Canal barges carried stowaway plants and animals in their hulls and ballast. In the mid-1800’s, the European faucet snail clogged water intakes across the region. The European pea clam, purple loosestrife, marsh foxtail, flowering rush – all used the canal system to enter the Great Lakes.
Chuck O’Neill says the spread of invasive species also tells the tale of human transportation.
“If you look at a map, you can pretty much say there was some kind of a right-of-way – railroad, canal, stageline – that was in those areas just by the vegetation patterns.”
Almost one hundred invasive species came to the Great Lakes this way before 1960. O’Neill says every new arrival had a cascading effect.
“Each time you add in to an ecosystem another organism that can out-compete the native organisms that evolved there, you’re gradually making that ecosystem more and more artificial, less and less stable, much more likely to be invaded by the next invader that comes along.”
(Sound of “Dragnet” theme)
The next one in the Great Lakes just might be the Asian Carp. It’s swimming up the Illinois River, headed toward Lake Michigan. Cameron Davis directs the Alliance for the Great Lakes.
“If this thing gets in, it can cause catastrophic damage to the Great Lakes, ‘cause it eats thirty, forty percent of its body weight in plankton every day, and plankton are the base of the food chain in the Great Lakes.”
The U.S. Army Corps of Engineers has installed an electric barrier in the Chicago Sanitary and Ship Canal that might stop the carp. But as long as the canals around the region remain open for shipping and recreation, it’s likely more invaders may hitch a ride or simply swim into the Great Lakes.
For the GLRC, I’m David Sommerstein.