Ecosystem Shock: The Devastating Impacts of Invasive Species on the Great Lakes Food Web
- Gwen White, PhD., Michael Murray, PhD., Sara E. Jackson
- Oct 21, 2004
Sometimes referred to as the “Sweetwater Seas,” the Great Lakes contain an incredible 20 percent of the world’ s surface freshwater. Their coastlines stretch over 10,000 miles, as long as the Atlantic and Pacific coastlines of the United States combined. The ecosystems supported by these lakes are equally vast - from varied shoreline to deepwater habitats. In monetary terms alone, the Great Lakes fisheries generate almost $7 billion each year through both commercial and recreational means.
Now, the entire food web – including the foundation of the vast Great Lakes ecosystem – is being disrupted by aquatic invasive species.
Alewife, sea lamprey, round goby, Eurasian ruffe, spiny water flea, zebra mussel and quagga mussel are some of the more devastating species to be introduced to the Great Lakes system. All have had extreme adverse affects on significant native aquatic species, such as the commercially important lake trout and whitefish. Individually, scientists have studied these nuisance creatures and brainstormed ways to attempt to eradicate their populations. At best, we have only been successful in figuring out ways to manage their populations and reduce their negative impacts. Meanwhile, additional potentially devastating invasive species, such as Asian carp, are already on the doorstep to the Great Lakes, threatening to enter.
As additional invaders enter the lakes and take hold, they place the entire Great Lakes fishery at an even higher risk of collapsing. And once such invasions occur, our options for recovery are quite limited. The lakes will not clean themselves of invasive species as they can, to a certain extent, chemical pollution once pollution sources are reduced or eliminated. Nor can we restore the food web simply by stocking high-profile species like trout and salmon or by limiting their harvest. We must develop and implement new management tools designed specifically to examine and protect the entire ecosystem — not just individual species. We must investigate and better understand food web dynamics and how they are being disrupted. And it is absolutely imperative that we stop new, even more damaging species from entering the Sweetwater Seas.
Congress is currently considering two highly effective opportunities for action. The first is legislation that would restrict activities (like ballast water discharges) that are the primary entrance routes for invasive species. This bill, called the National Aquatic Invasive Species Act (NAISA), could prevent new harmful species from invading the lakes. It would not, however, address the damage that is being done by the invasive species already present. Fortunately, another set of legislative proposals would finance a Great Lakes restoration initiative designed to restore habitat and species that have already been harmed. The Great Lakes restoration bills would provide billions of dollars for these and other restoration purposes. It will take a combination of these effective programs to ensure the survival of a healthy and diverse Great Lakes ecosystem.
Ecosystem Shock
The Great Lakes contain 20 percent of the world’s surface freshwater. Their coastlines stretch over 10,000 miles, as long as the Atlantic and Pacific coastlines of the United States combined. The ecosystems supported by these lakes are equally vast - from varied shoreline to deepwater habitats. In monetary terms alone, the Great Lakes fisheries generate almost $7 billion each year through both commercial and recreational means. Now, the entire food web – including the foundation of the vast Great Lakes ecosystem – is being disrupted by aquatic invasive species.
