by Joseph Baustian
What has two eyes, eight fins, and can jump 10 feet in the air?
An Asian carp of course!
Asian carp have been decimating the Mississippi River watershed for the past few decades and now have their sights set on the world’s largest freshwater lake system—the Great Lakes. Asian carp are on the verge of invading the Great Lakes through the Chicago Sanitary and Ship Canal. This invasion would be devastating to native fish populations and potentially lead to the collapse of local Great Lakes fisheries, a $5 billion industry.
Asian carp are voracious filter feeders that can grow rapidly and outcompete native species for resources. Lakes Michigan, Huron, and Erie are particularly threatened by Asian carp because they are highly productive systems, and provide suitable habitat for Asian carp reproduction. Currently, the only thing preventing their spread into the Great Lakes is an electrical barrier on the Chicago Sanitary and Ship Canal. Although the barrier is not 100% effective; so far it has managed to keep large numbers of Asian carp out of the Great Lakes.
While fish literally jumping into your boat may sound like a good thing to fisherman, it can be dangerous (Check out this video of jumping silver carp). Adult silver carp weigh 20 to 30 pounds; they have caused numerous injuries by striking boaters in the head or knocking them out of their boats. To put this into perspective, being hit by a jumping silver carp is like being hit with a bowling ball. I don’t know about you, but dodging bowling balls does not sound like a leisurely way to spend an afternoon on the water. In some areas along the Mississippi River Asian carp are so numerous that 8 out of every 10 fish are carp,—that’s a lot of jumping fish to dodge.
Once Asian carp become established in an area, little can be done to reduce their populations. One community has developed a new strategy they hope will be effective. The small Mississippi River town of Grafton, Illinois, has begun a joint venture with a Chinese company to harvest and ship more than 35 million pounds of carp to China in the next 3 years. You won’t find Asian carp at your local fish shop (American’s don’t find them palatable); however, they are popular in China and are even marketed as “upper Mississippi wild-caught carp with so much energy they can jump.” Although exporting them to China is a potential solution, the low price point of 15 cents per pound may be a disincentive to solving the invasive carp problem. But the price may soon rise as new ways to use Asian carp for fishmeal, animal feed, and Omega-3 fish oil gain industrial acceptance.
The question remains—will commercial export be effective at reducing Asian carp populations? We will just have to wait and see.
If successful, it offers a plausible and economic solution if Asian carp do invade the Great Lakes. As detailed above, currently the electrical barrier prevents their expansion, however one inopportune power failure could mean disaster for the Great Lakes. Given the fragility of the current system, a more permanent solution has been proposed, which includes closing the connection between the Chicago Sanitary and Ship Canal and Lake Michigan. While this would be effective, it would end all shipping between the Great Lakes and the Mississippi River basin,—a scenario even less palatable than the invading Asian carp.
Although neither an electrical barrier nor closing the connection provides an optimal long term solution, the current electrical barrier allows us to “head them off at the pass” and prevent the destruction of the Great Lakes ecosystem and fishing industry. The challenge remains to find an innovative solution to invasive species such as Asian carp.