The Pop's Place station was similarly sampled on July 18, 1975. Seven cutthroat trout averaging 

 6.3 inches long and 54 brook trout averaging 4.8 inches long were captured in a 400-foot section, 

 again showing there was not a complete kill of trout. No sculpin were observed in the section. 

 However, very few sculpin were found at this location in sampling prior to dam failure (Spence 

 1975, p. A- 130). 



The trout population estimate made in September, 1975 at the Flesher station showed that, 

 compared to 1973, there was a total reduction of 83% for all sizes of cutthroat trout and 77% for 

 brook trout after dam failure (Table 7). Most of the reduction in cutthroat occurred in the smaller 

 size groups (1 .5-4.9 inches). There was also a reduction in larger sizes of cutthroat. Confidence 

 limits are at the 80% probability level for both the 1973 and 1975 estimates. The data indicate 

 that cutthroat were either unsuccessful in spawning during the spring of 1 975 or there was a large 

 mortality of eggs and/or fry in gravels after spawning took place. There were insufficient 

 recaptures of marked brook trout in 1975 to estimate their numbers by separate age groups. The 

 reduction in total numbers was statistically significant at the 80% probability level for both 

 cutthroat and brook trout. 



Stream Sediment and Tailings Analyses 



The data presented show what metals were present in the mine tailings behind the dam and the 

 principal metals found in sediments in the Blackfoot River before and after dam failure. 



Results of analyses of the sediment sample collected above Shoue Gulch in 1975 are given in 

 Appendix F. The analyses show that only small amounts of each metal were carried in 

 dissolved form (Table I) but high concentrations were carried in suspended form (Table IV). 

 Some of the water quality analyses that reported dissolved fractions showed the same results, i.e., 

 only small amounts of metals were dissolved in runoff waters (See Appendix B). 



14 



