832 CHERRY et al. 



TABLE 2 



FIRST STATISTICAL (OR THRESHOLD) AVOIDANCES BY 



THE COMMON SHINER {NOTROPIS CORNUTUS) 



SUBJECTED TO VARIOUS TREATMENTS AND 



TEMPERATURE CONDITIONS 



* Abbreviations ai"e TRC, total residual chlorine; CRC, combined 

 residual chlorine; and FRC, free residual chlorine. 



than the CRC fraction of TRC treatments (0.195 to 0.163 mg/liter, 

 respectively). 



The common shiner's response to ammonia nitrogen resulted in 

 no significant avoidances in the range tested, ~0.015 to 

 0.275 mg/liter (Fig. 1). In most treatments the species tended to 

 spend greater time in the ammonia-treated water. At the highest 

 concentration tested (0.275 mg/liter), which greatly exceeded am- 

 monia nitrogen levels in chloramine trials (Table 2), residence time 

 was nearly the same as during the control period. 



DISCUSSION 



The common shiner actively responded to chlorinated water by 

 avoiding TRC and CRC exposures after a minimal concentration level 



