Invasive Species in the Great Lakes

Invasive species have become a growing problem across the United States as we have become more interconnected with the outside world. One example making headlines is the establishment of exotic snakes in Florida. Last year, a female Burmese python — at nearly 18 feet and 165 pounds — was found in the Everglades carrying 87 eggs. Pythons were first discovered in the Everglades in 1979, having been introduced as discarded household pets. They eat everything: birds, bobcats, deer and even alligators. With no natural predators, their population has skyrocketed and is now estimated to be, conservatively, in the tens of thousands. 

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Here in the Great Lakes region, we don’t need to worry about tropical snakes, but we still have more than our share of non-native species. Since the 1800s, there have been nearly 200 non-native species of fish, mollusks, worms, plants and algae that have taken up permanent residence in the Great Lakes ecosystem.

The U.S. Department of Agriculture calls a species “invasive” if it causes harm to human health, economic growth or the environment. Several non-native Great Lake species meet the “invasive” criteria, including the sea lamprey, round goby, spiny water flea, and the zebra and quagga mussels.

When it comes to dealing with the real and potential harm caused by invasive species, policymakers and the public should consider several points. The first is that in almost every case, once an invasive species becomes established, be it a python or a zebra mussel, eradication is no longer a viable option. Resources are far better spent on prevention or on efforts to impede the spread. While there will continue to be many new non-native species, target those that are “invasive.” One-size-fits-all solutions that create bureaucracy and paperwork should be avoided. Programs must be both cost effective and able to document environmental improvements.

It is important to look for the root cause of the “invasion.” In the Everglades, it was the accidental or deliberate release of pet pythons. In the Great Lakes, the primary vehicle for the introduction of non-native species is the use of ballast tanks by ocean-going cargo ships. For stability purposes, ships often filled these tanks with water from outside the Great Lakes and then discharged this water once they had entered the Great Lakes. More than a third of the 200 non-native species in the Great Lakes region have been discovered since the opening of the St. Lawrence Seaway in 1959.

Close to 600 ocean-going freighters, or “Salties,” enter the Great Lakes each year, carrying about 5 percent of the total Great Lakes’ cargo. These ships are now required to discharge any ballast water at sea prior to entering the St. Lawrence Seaway. They are then required to submit a ballast water status report in Montreal. It is estimated that about 90 percent of the incoming ships are now free of ballast water.

The real trick to preventing harm from invasive species is to identify threats before they begin doing damage. The biggest threat right now comes from Asian carp. This invasive fish reproduces rapidly, has a voracious appetite, and can weigh up to 100 pounds. The Asian carp has been moving north through the Mississippi River and its tributaries. The Chicago Area Waterway System (CAWS), with its set of commercial canals, connects Lake Michigan to the Illinois River, which in turn connects to the Mississippi River.

To effectively deal with these issues, policymakers need to include all stakeholders, set realistic goals and try new methods. Earlier this summer the Great Lakes-St. Lawrence River Basin Aquatic Invasive Species Partnership put forth a resolution to “achieve long term success in preventing new introductions and reducing the treat of aquatic invasive species” in the Great Lakes Basin. To accomplish this, the Partnership calls for the use of rapid response activities, early detection and the use of applied research. The plan set forth by the Partnership is promising.

Going forward, we need to acknowledge that there will always be an invasive species problem. To minimize this threat, all stakeholders — including state and federal agencies plus Canadian counterparts and private industry — must work together. This will require the sharing of information to establish strategies with measurable outcomes that weigh environmental, monetary and commerce implications.


Michael Heberling, Ph.D., is president of the Baker College Center for Graduate Studies and a member of the Board of Scholars at the Mackinac Center for Public Policy, a research and educational institute headquartered in Midland, Mich. Permission to reprint in whole or in part is hereby granted, provided that the author and the Center are properly cited.