March, 1963 Larimore & Smith: Fishes of Champaign County 



303 



streams, a 50-foot electric seine, powered 

 by an 11-ampere, 230-volt alternating cur- 

 rent generator, was used. The generator 

 was usually left near the equipment truck, 

 and the electric lead wires were run off a 

 reel having a commutator through which 

 power was supplied as the electrodes were 

 moved up and down the stream. 



In the blocked-off areas, we took 77 

 samples, all within a short period of time 

 (July and August, 1959), thus keeping at 

 a minimum the effects that seasonal 

 changes in fish distribution and abundance 

 might have on our samples. Because for 

 each blocked-off area we made and kept 

 a record of the number of individuals of 

 each species in the sample and their total 

 weight, we refer to a sample from such an 

 area as a quantitative sample. 



To supplement the sample taken within 

 each blocked-off area, we seined nearby 

 habitats, figs. 2 and 3. An indefinite num- 

 ber of hauls was made with a 20-foot by 

 4-foot nylon minnow seine of three-six- 

 teenths-inch mesh. These "cruising" sam- 

 ples usually added several species to the 

 list of fishes taken at each locality. Ma- 

 terial obtained outside the blocked-off 

 areas was not included in the quantitative 

 samples. Fish in the "cruising" samples 

 were not measured or weighed. 



The reliability of our quantitative sam- 

 ples was not determined. We recognized 

 the selectivity of electrofishing in differ- 

 ent habitats and for different species of 

 fishes. For obvious practical reasons, we 

 could not adapt our equipment and pro- 

 cedure to produce the greatest efficiency 



Fig. 3. — Seining a shallow pool in the Sangamon River near Mahomet. Habitats of this 

 type contain suckers and minnows. In 1959, collecting with a minnow seine in such habitats 

 usually yielded species not collected with an electric seine in nearby blocked-off areas. 



