1998 . All stations were sampled between 31 August and 23 September 1998, 

 taking 26.00 hours, with sampling times ranging from 0.5 to 1.0 hour (Table 5). 

 Sampling was conducted in full daylight between the hours of 8:45 AM and 6:30 PM. 

 The ranges for physical measurements during the 1998 sampling season were as 

 follows: air temperature, (not measured); water temperature, 73.9-86.9 F; dissolved 

 oxygen concentration, 5.0-8.4 ppm; Secchi disk transparency, 5.9-23.6 inches; 

 specific conductance, 443-835 umbos; surface velocity, 0.0-1.1 ft/s; water depth, 0.0- 

 14.0 ft (Table 5). 



C. Catch Rates in Numbers of Individuals 



In this report, for each year (1994-1998) catch rates of the number of 

 individuals collected per hour of electrofishing are calculated for each of the seven 

 Illinois River navigation reaches (Figure 1). Similar summaries are presented for fish 

 weights. Common names used throughout this report follow Robins et al. (1991). 

 Common and scientific names are listed in APPENDIX A. Number of individuals of 

 each fish species collected per hour of electrofishing and species rankings by 

 waterway reach and year are summarized by Tables 6 through 15. 



Numbers of Fish Collected From 1994-1998, we collected a total of 25,921 

 fish representing 62 species (plus five hybrids) from fourteen families during 125.70 

 hours of sampling at 26 sites on the Illinois Watenway and a single site on the 



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