Map courtesy of the Christian Science Monitor.
Years of fears that the Asian carp would invade the Great Lakes and start out competing valuable commercial and recreational fish like salmon and perch for food are now beginning to being realized.
Earlier this summer the first live Asian carp - a bighead carp to be exact - was caught between the electric barrier in the Chicago Area Waterway System and Lake Michigan.
This capture proves that live Asian carp have unimpeded access to the lake and validates the accuracy of earlier environmental DNA (from microscopic bits of tissue shed from the fish) that indicated the fish were nearby.
In March, the U.S. Supreme Court denied Michigan’s renewed request for a preliminary injunction to close the Chicago-area locks. The renewed motion came in response to the DNA evidence of the carp getting past the O’Brien Lock and into Lake Michigan.
David Lodge, director of Notre Dame’s Center for Aquatic Conservation, and an expert in invasive species, commented that, “While some Asian carp may already have escaped into Lake Michigan, the establishment of reproducing, self-sustaining populations in the lake are far from certain.
“The likelihood of invasion though increases as the number of escaping carp increases. This is why management to prevent invasion of the Great Lakes is so urgent.”
A lot of the concern with the Asian carp - collectively bighead and silver carp - entering the Great Lakes is that they will deplete the zooplankton, which is also the main food source for mussels, fish larval, and some adult fish.
Fishermen net bighead carp from the Illinois River. AP photo.
Asian carp can weigh up to 100 pounds, and grow up to a length of over four feet. They’re well suited to the climate of the Great Lakes region, which is similar to their native Asian habitats.
The U.S. Environmental Protection Agency fears that the carp would disrupt the food chain that supports the native fish of the lakes. “Due to their large size, ravenous appetites, and rapid rate of reproduction, these fish could pose significant risk to the Great Lakes ecosystem,” said the agency.
To further study the problem and come up with solutions Notre Dame and its partners have just received a $2.5 million grant for research on invasive species in the Great Lakes. Invasive species such as zebra mussels are already a huge problem, costing the region more than $200 million annually by disrupting the lakes fisheries and damaging waterway infrastructure by clogging water intake values.
The new information will be used to help authorities prepare for new invasions and control the current non-native populations. The Asian carp invasion will play a major part in the research study.
In 2006, the Great Lakes Protection Fund gave a combined grant of $1.1 million to Notre Dame, The Nature Conservancy’s Great Lakes Program, and the University of Georgia to research strategies to improve ecosystem-wide management of the species in the lakes and adjacent inland water bodies.
The Great Lakes are a key beachhead for invasive species to enter into the United States. Ships arrive in the lakes from ports around the world. Often bearing non-native species in their ballast water, which is water carried in the ships’ hulls to make them heavier and less likely to roll. When entering a port, the water is discharged from the ships.
In the 2006 study, with some success Notre Dame and its partners tested the effectiveness of a series of intervention strategies, including educational activities, inspections, and boat washing stations to help slow the spread of already established invasive species.
At the time, John Andersen, director of the Conservancy’s Great Lakes Program, commented that, “Prevention is more effective and less expensive than dealing with an invasive species after it has arrived and started doing damage.”
Right now, the Illinois Department of Natural Resources will continue to work with nearly 60 Chicago area bait shops in September to test for Asian carp DNA and educate bait shop owners on how to tell the difference between Asian carp minnows and other fish with similar characteristics that are commonly used as bait. Also, barrier defense operations will also continue to remove silver and bighead carp on the downstate waters where the fish are known to be present.
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