Table 10. — Change in the abundance of organisms''- in riffle areas of various streams 1 week after 

 treatment and in control streams, Lakes Superior and Michigan, 1962-6'4 



[increase or decrease is greater than 20 percent change; increase (+), decrease (-), little or 



no change (0)] 



Organism 



Treated streams 



Wilson 

 Creek 



Three 



f^le 



Greek 



Iron 

 River 



Sturgeon 

 River 



Buck 



Bay 



Greek 



Simny 

 Brook 



Control streams 



Little 

 Garlic 

 River 



Little 



Scarboro 



Creek 



Insects: 

 Plecoptera 



Nemouridae 



Perlidae 



Chloroperlidae . . 

 Ephemeroptera 



Caenidae 



Ephemerellidae. . 



Heptageniidae. . . 



Leptophlebi Idae . 



Baetidae 



Odonata 



Gomphidae 



Trichoptera 



Rhyacophilidae. . 



Psychomyiidae. . . 



Hydropsychidae. . 



Phryganeidae . . . . 



Lepidostomatidae 



Brachycentridae . 

 Coleoptera 



Elmidae 



Diptera 



Tipulidae 



Chironomidae .... 



Heleidae 



Rhagionidae 



Empididae 



Other invertebrates : 



Annelida 



Crustacea 



Isopoda 



Amphipoda 



Hydracarina 



Mollusca 



Gastropoda 



Pelecypoda 



Increase 



No change 



Decrease 



1 







15 



•*■ Based on groups that contained five or more individuals per square foot (0.092 m.^), 



12 



