Chicago Sun-Times
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Fish kill: A Chicago biologist's help

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Philip Willink had enough. So he did something.

The fisheries biologist for the Field Museum was so fed up with misinformation about Asian carp, especially around the Chicago area--misinformation such as the bighead found near the Lockport Lock as being the closest an Asian carp was found near Lake Michigan.

It's not. He pointed out a silver carp was found a couple miles downstream of the barrier in 2004.

At any rate, Willink established a Web site--http://sites.google.com/a/fieldmuseum.org/pwillink/asian-carp-in-chicago-faqs--to help dispell some of the misinformation.

Hw writes in an extremely straight forward and accessible manner, and puts out the facts. I highly recommend it.

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5 Comments

This is great information - thanks for posting this, Dale!

If these fish make up most the fish biomass in the rivers they occupy, one would have to assume it will be the same for Lake Michigan once they make it there.

It seems that this should have been handled when they first escaped, maybe they need to reboot the entire Mississippi river network if the only meaningful fish in these waterways are these carp.

Everyone in Chicago media should be required to read this information before reporting or commenting on Asian carp. Thank you Mr. Bowman for the link.

Very informative and seemingly well thought out. But I do have issues with this section:

"We have been using electricity to survey fishes since the 1930s. Biologists have a lot of experience using this method, and it is one of the best for collecting fishes. However, when you are in the field you always notice a few individuals getting away. Whether it is something about those particular fish, or water chemistry, or something in the habitat, or some other factor, electricity is not 100% effective"

I do not think this is a valid comparison. Electro-fishing involves a couple of guys dangling electrodes in the water and seeing what floats up. This is vastly different from the wall-to-wall fixed electrodes of the barrier. Furthermore, the barrier is not designed to stun the fish, only to make them turn around. Now, if he were to say that he has seen fish swim toward the electo-fishing electrodes, then I would start to question the effectiveness of the barrier.

The main point I wanted to make is that electricity is capricious in water. The response of a fish to electricity is dependent upon the strength of the electric field, the orientation of the electric field, and the orientation of the fish. Possible responses of a fish to electricity are being stunned, swimming from the electric field, swimming into the electric field, or swimming along the lines of equal strength of the electric field. (The last possibility is difficult to describe without a diagram, sorry.)
I have seen all four responses. Yes, I have seen a fish swim into an electric field. One example is a large redhorse that followed my electrode like a dog on a leash. By moving the electrode in the water, I was almost able to get the fish to swim a complete Figure-8 in front of me. I have also seen large common carp swim into the electrodes of shocker boats.
The combination of electricity, water, and fish is a tricky business. In theory the Electric Barrier in the Chicago Canal is designed to minimize such problems, but there are no guarantees. Electricity is extremely effective, but not 100% effective all the time, in my opinion.

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This page contains a single entry by Dale Bowman published on December 8, 2009 9:45 AM.

Fish kill: A Hall of Famer's take was the previous entry in this blog.

Waiting on deer numbers: Illinois Hunting Report is the next entry in this blog.

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