Surveying Fox River fish
Outdoors with Mike Norris - July 26, 2002

Monitoring the quantity of Fox River fish and their health is one of several duties area fisheries biologists are in charge of.
Sampling stations are identified and established along the entire length of the river and surveys of fish populations at each station are staggered so that each station is sampled at least once every five years.

One such Fox River fish sampling station occurs upstream from the Fabyan Forest Preserve, located just north of Fabyan Parkway on Ill. 31 in Geneva. This station was the site for a recent fish sampling conducted by fishery biologists from the Illinois Department of Natural Resources.

IDNR Northern Illinois Stream biologist Steve Pescitelli led the survey. On hand to observe were officials from the Fox River Water Reclamation District, Kane County Forest Preserve, Illinois Environmental Agency, Illinois Natural History Survey, the Sierra Club and Southern Illinois University.

Pescitelli's fish sampling laboratory is an especially equipped aluminum jon-boat fitted with a portable electrical generator capable of producing 3,500 watts and 30 amps of current.

Electrical current is directed by cables from the generator through three fiberglass poles which reach out 6 feet in front of the boat. Flexible copper coils located at the end of the three poles release the current into the water and an electric field forms 8 to 10 feet in front of the coils. When this current comes in contact with an organism, its neurons fire simultaneously, causing momentary paralysis of any fish within the field.

District 7 Fisheries manager Frank Jakubicek provided a second electro-shocking jon-boat for the Fabyan sampling. Jakubicek is in charge of monitoring and stocking the Chain 'O Lakes near Antioch.

The sample area begins just south of the Geneva Government Center and runs back to the foot bridge, said Pescitelli as his assistant fired up the 10 horsepower outboard .

"We should be back to the launch ramp with a bunch of fish in about 40 minutes," said Pescitelli.

Electro-shocking targets shoreline-oriented fish species. Pescitelli began his down river run about 10 feet off the west shore. Jakubicek positioned his boat an equal distance along the east shore. As each boat moved down river, the electrical current field stunned fish, allowing them to rise to the surface so the biologists could net, take samples, revive and release the fish, healthy but slightly dazed.

All stunned fish were placed in an aerated holding tank until all had been sampled. Fish were identified, measured in millimeters, weighed, and examined for external evidence of ulcers, lesions, fin rot and structural deformities. Nearly all the fish were then released at the sampling site.

Only a handful of channel catfish and carp showed signs of eroding barbells or looked pale in color. These fish were kept and will be sent to the Illinois Environmental Protection Agency laboratories for further examination to determine the cause of their stress.

From the data collected, Pescitelli can determine the number of species collected, catch per unit effort, percentage of diseased fish and number of non-native fish for the sampling site.

Once the data is compared with data from the prior survey five years earlier, Pescitelli can determine whether the fishery remains viable, or whether there are signs that the fishery is declining from water degradation or oxygen loss.

"Today's sampling is indicative of what we found five years ago," Pescitelli said. "We had both large and smallmouth bass, walleye, bluegill, both channel and flathead catfish and a number of species of carp in the the holding tank. I'm very pleased at what we found today.

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