effective on fish as preparations which contain 

 5 percent rotenone . Hester (1958) found how - 

 ever, that Pro-noxfish was somewhat less effec- 

 tive on 7 species of fish than Noxfish which has 

 5 percent rotenone . 



The principal problem pertaining to the 

 application of rotenone in a stream involved a 

 determination of the quantity of toxicant needed 

 to provide an uninterrupted and adequate con- 

 centration for an effective period of time . The 

 fact that a chemical agent stretches out and 

 becomes greatly diluted over a relatively short 

 distance in running water was observed during 

 many collections of fish in the park with cresol 

 anesthetic. It appeared that quantitative esti- 

 mates of the concentration of toxicant, the dur- 

 ation of exposure, and the factor of dilution 

 could be obtained with a dye and comparator 

 tubes or with stock salt and a resistivity meter. 

 Both methods were tried but the latter one 

 proved the better since some observations had 

 to be made over long distances at night in tur- 

 bid water and in stormy weather (Lennon, 1959). 



The salt -resistivity technique was exten- 

 sively employed in prereclamation surveys on 

 Indian and Abrams Creeks . For example, salt 

 was added to Indian Greek on one occasion at an 

 average rate of 12.2 ppm for a 15 -minute period. 

 The bolt of salt water reached a point 3 .5 miles 

 downstream in 2 hours and 34 minutes . It had 

 become stretched out and required more than 2 

 hours to pass the check point. It had become 

 diluted from 12.2 to 2 ppm. On the basis of 

 similar trials at different rates of stream dis- 

 charge, the stretch-out dilution, and velocity of 

 a bolt of rotenone emulsion moving downstream 

 were estimated. Strengthening stations were 

 located downstream so that additional rotenone 

 could be superimposed on the residual toxicant 

 in the stream to maintain a killing concentration 

 for the required period of time . The data on 

 velocity also contributed to the timely deploy- 

 ment of crews to man the strengthening stations 

 and to collect fish . 



The particular problems in respect to 

 the fish in Indian and A±)rams Creeks were these: 

 what species were present, and what concentra- 

 tions of rotenone and lengths of exposure were 

 required to kill the more resistant of them? 

 Samples of the fishes in both streams were 



obtained with electrofishing gear and cresol . 

 The extensive collections made in Indian Creek 

 showed that rainbow trout, eastern brook trout, 

 and longnose dace were the only species present 

 in the section of stream to be reclaimed. Par- 

 tial collections and reports of anglers on lower 

 Abrams Creek indicated that there were at least 

 30 species of fish present. They included 

 lampreys, gizzard shad, trout, suckers, carp, 

 dace, shiners, stoneroUers, catfishes, killifish, 

 sauger, darters, rock bass, smallmouth bass, 

 sunfish, drum, and sculpin. 



Specimens from the collections were 

 used in streamside toxicity trials with Pro-nox- 

 fish. The trials were conducted in hatchery 

 troughs set up on Indian Creek and on Abrams 

 Creek to avoid the possible complications due 

 to different waters or different water tempera- 

 tures. Water for the troughs was taken directly 

 from the streams. The test fish were held in 

 livecars in the streams until used. 



On Indian Creek, all rainbow trout (3.9 to 

 13.2 inches long) and longnose dace (3 to 5 inches 

 long) tested were killed when exposed to 0.5 ppm 

 or more of the toxicant for 1 hour at water temp- 

 eratures of 56 to 59° F. Several trout (4 to 5 

 inches long) survived up to 105 minutes in a 0.1- 

 ppm concentration at 58° . On the basis of the 

 trials, it was decided that a minimum concentra- 

 tion of 1 ppm of toxicant would be maintained for 

 1 hour throughout Indian Creek to eradicate the 

 trout and longnose dace . 



On Abrams Creek, a total of 230 fish 

 (0.5 to 23.2 inches long) of at least 14 species 

 was used in toxicity tests . The concentrations 

 of the toxicant tested ranged from 0.1 to 3.25 ppm, 

 and the water temperatures ranged from 64° to 

 72° F. (table 1). Carp were more difficult to 

 kill than other species. Three specimens, 14.4 

 to 18.5 inches long, died only after a continuous 

 exposure of 5 to 6 hours in a concentration of 0.1 

 ppm of the toxicant at 64° . Another carp, 18.6 

 inches long, turned over after 30 minutes in a 

 1-ppm concentration at 67° and appeared to be 

 dead after 3 hours of exposure. It recovered 

 fully however, after it was removed from the 

 test trough and placed in a livecar in the stream. 



StoneroUers were relatively resistant to 

 the toxicant and survived up to 3 hours and 55 



