Field Notes
U.S. Fish & Wildlife Service
Field Notes Entry   
Shocking Warfare
Midwest Region, July 10, 2011
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MLES Electrofishing Control Box
MLES Electrofishing Control Box - Photo Credit: n/a

In the warfare against carp, there is promise of a new weapon. Electrofishing has at best been marginal in the fight against the invasive carp. The mystery of how some fish respond to electricity while some don’t has challenged fishery biologists to explore new electrical pulse rates, duty cycles and voltage fields to tease the fish of interest to come to the boat.

Since silver carp tend to jump and sink or have some semblance of ESP in detecting the field of the boat and as such we have been working to tweak the settings of our unit to induce electro-taxis in these fish for years now.

To date the only method that has shown promise was a surprise attack in scaring them into shallow water where we could get them after they jump. There has been a recent advance however with the production of the MLES electrofishing box developed by Mid-West Lake Management. The new box uses a redesign of old technology that incorporates digital infinite adjustment for the user, rectified AC, and a computed calculation of power as a “read-out” on the box.

Now the biologist has the ability to tweak the voltage and pulses in digits rather than a range to find a field that is most effectual on the species within a given water body. To test the unit on other species, I recently met with Dr. Jan Dean who instructs the FWS electrofishing course and Arkansas’ Game and Fish biologist (Lee Holt). We electrofished for snakehead and alligator gar in Eastern Arkansas. Lee’s summary of the system was that he had seen more effective shocking of forage (gizzard shad) than ever before, and though we didn’t find alligator gar, we did capture one snakehead.

Our office has worked closely with Midwest Lake and their physicist (Tom Lehman) to learn more about the nuances of electrofishing. Through our experiments and a little trial and error, they have been able to incorporated new software upgrades that will maximize electrical power the box can deliver for our needs. Our preliminary efforts show some success in creating taxis of silver carp. Our future efforts will seek to document effective control box settings that we can use to monitor and remove carp throughout our river.

Contact Info: Wyatt Doyle, (573)876-1911 ex 111, wyatt_doyle@fws.gov
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