Let’s take a step back from the ocean and dive into some freshwater problems plaguing my home state of Illinois. Several species of invasive carp originating from Asia have been wreaking havoc on the ecosystems of waterways in Illinois and surrounding states. These carp were introduced to assist in cleaning agricultural ponds in the South in the 1970′s. Eventually, the Asian carp escaped and have been making their way up the Mississippi River ever since. Today, freshwater ecologists are finding evidence that the Asian carp has made its way into Lake Michigan, thereby threatening the entire Great Lakes ecosystem.
All five of the Great Lakes are connected in some way. When the invasive Zebra mussel was unloaded from ship ballast tanks, they spread rapidly throughout the Great Lakes. The Zebra mussel has increased water clarity in the lakes, which causes more algae to grow. The Asian carp, much like the Zebra mussel, could cause a complete collapse of the $7 billion fishing industry in the Great Lakes. The Asian carp also threatens to displace many of the natural species in Great Lakes ecosystems, much like the Asian carp has already accomplished in Illinois rivers and streams.
To determine whether or not there were Asian carp in Lake Michigan, ecologists took 2800 water samples and used molecular methods to determine the invasive fish’s presence. There were 58 “hits” of Asian carp DNA, but some argue this may be a false positive due to the possibility of bird droppings contaminating the lake with carp DNA. But, its still quite likely that the carp have made it into the lake system.
Even though Asian carp may have made it to Lake Michigan, despite the electric barriers that have been in place for many years, it may not be too late to stop them. Further work with the Illinois Department of Land and Natural Resources as well as the Corps of Engineers, steps could be taken to seal off the canals that feed into Lake Michigan from the greater Chicago waterways. As long as the carp still have a low population number in Lake Michigan, it is likely they will have a low number of successful fertilization. Something must be done quickly because the Asian carp have been known to become the dominant species quickly through high fertilization rates and a lack of natural predators.
“Asian carp may have reached Great Lakes”
-By John Stengel