Asian Carp are knocking at the (electric) fence

It's been sometime since this blog has talked about looming threats to the Great Lakes Basin. Unfortunately the reality is that there continues to be a multitude of environmental issues knocking at the locks- or in this case, the electric fence barrier in Chicago.

A couple species of exotic and invasive Asian Carp have made their way up the Mississippi River and are posed to get into Lake Michigan via the Chicago Lock's. The threat has alarmed everyone from scientists to fisherman and recreational boaters because once into the lake, this fast-growing filter feeder would severely disrupt phytoplankton production and potentially cripple the commercial and sportfish industries. To boot, the Asian Carp responds to danger (i.e. boat engines) by jumping out of the water, sometimes injuring boaters. Imagine water skiing and having to dodge jumping fish!

The voracious plankton feeders wer first introduced to fish aquaculture pens down in Arkansas to control algae blooms and parasites, supposedly 'improving water quality'. Unfortunately this has become a classic example of biological introductions gone wrong.



Of course the aquaculture industry assured us that these fish couldn't reproduce (triploid genome) and wouldn't be able to escape from the pens - in effect they poised no risk. Well, all bets were quickly off because it took only a couple of years for a few large floods to carry the fish out to major waterways and into the Mississippi drainage. And apparently a few of them didn't get the triploid memo rbecause they have both established feral breeding populations throughout most of eastern United States.

Because they lack native predators or competitors, their populations are rapidly multiplying as they consume all available phytoplankton - the base of the food web. They grow to about 1 metre and can weigh as much as 100lbs.

Currently, the only thing keeping them out of the Great Lakes is a weak electric current across the Chicago river, but most managers fear that its only a matter of time before they find a way around the barrier and into the Lakes. They predict that once established in the lakes, they have the potential to wipe out the $7 billion/year fishing industry in the Great Lakes. And this doesn't really consider the irreversible ecological damage that will result from their introduction.

The U.S. Fish and Wildlife Servce has established an Asian Carp Working Group to develop a management plan to prevent their spread into the lakes, but the situation seems dire. Legislators have put a ban on their import or trafficking within the country but if anything, the legislation will only delay their eventual establishment in the Lakes.

The next few years will be critical in terms of monitoring their movements as they inch closer and closer to the lakes.  I for one and am not looking forward to wearing a helmet on the open waters!