Bad as it would be for Asian carp to get into the Great Lakes, new research from the University of Michigan shows the damage would be even worse than previously estimated.
The study, published August 12 in the research journal Freshwater Biology, concludes that Asian carp would be able to survive in a larger area of Lake Michigan than previously thought and have a high likelihood of becoming established, should they get in.
Previous research by the U.S. Geological Survey in 2017 had analyzed that the algae-based food resources Asian carp feed on would be most abundant within a one-mile distance from shore, all around the lake, explained National Wildlife Federation spokesperson Drew YoungeDyke.
“That really wouldn’t have minimized (the damage) a whole lot because the other fish are where the food is too,” he said. Prey fish depend on plants and algae near shore as well. “Most of those lake-run fish, they are coming into the river mouths and bays and going up river, think about Salmon, to spawn. So during those spawning times, they would be competing with Asian carp in those areas too.”
What the study showed was that bighead and silver carp also can feed on detritus — fecal deposits from quagga and zebra mussels, invasive species themselves — which now “coat the lake bottom.”
“And because they’ll be able to eat that too, they are not just limited to within a mile of shoreline, that they will be able to spread out in all parts of the lake at different times of the year,” YoungeDyke said.
The researchers concluded that the “diet plasticity” of Asian carp would allow “the potential for cross‐lake migration corridors that may facilitate and accelerate lake‐wide movements.”
“This study confirms that Asian carp are even a larger threat to our Great Lakes,” said Marc Smith, Great Lakes director of conservation partnerships for the National Wildlife Federation. “Congress must act with urgency to approve the Brandon Road plan to stop Asian carp from getting into Lake Michigan. From there, these invasive fish could spread throughout the Great Lakes region, undermining our fisheries, outdoor recreation, and the lake-based tourism that sustains entire communities around the Great Lakes. Our freshwater way of life is at stake. Congress must act swiftly to stop Asian carp.”
Last month, the Army Corp of Engineers unveiled its plans for rebuilding the Brandon Road Lock and Dam in Joliet, Illinois, to keep Asian carp out of the Great Lakes. The 10-year, $830 million would include bubble curtains, sound repellents and electric barriers to keep the fish from passing through the Chicago Canal.
“We call it making Asian carp run the gauntlet because it creates that engineered channel with all those technologies in it,” YoungeDyke said. “. . . We fully support this plan. This is really the only shot that we have to get stronger structural measures in place. There still has to be the fishing out below the river and below the dam, but this is our one shot to get this in place.”
Further, the project will be built so that new technologies can be added when they are developed.
“When you look at the price tag around $800 million, that’s one-time construction costs of $800 million dollars versus a $7 billion annual sport fishery, not even to mention the tourism industry at risk. When you look at that big price tag, it actually really is just a drop in the bucket compared to the annual economies that are at risk if Asian carp get in the Great Lakes,” he said.
It is a project that will take up to 10 years to fully implement, so it is important Congress not delay on getting the project rolling, he contended. Officials are pushing hard to promote the plan, he said.
YoungeDyke also contended that if the Great Lakes region expects support from other parts of the country, it is going to have to support Asian carp reduction and control programs along the Mississippi River basin, particularly in Kentucky Lake and Lake Barkley in Tennessee.
YoungeDyke warns that if Asian carp make their way into the Great Lakes, they’ll also eventually find their way into inland lakes and rivers.
“There are some inland lakes and rivers than have dams that would, especially older dams, that would prevent their (passage), but a place like Lake Charlevoix and that whole tourism industry has no barrier between where they would come up along the lake, go into the Pine River channel, go into Round Lake and Lake Charlevoix and have access to the estuary that actually provides a lot of the spawning habitat for the fish that go up into the Jordan River, which is a blue ribbon trout fishery,” he said.
Asian carp are known for jumping and have seriously injured boaters who get hit by one.