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SAMPLING METHODS AND MATERIALS 



Sampling methods used to collect aquatic macroinvertebrates on the 

 Yellowstone River included kick nets (figure 15), Water's round samplers 

 (figure 16), and Hester-Dendy multiple plate artifical substrates. 



The kick net, essentially a Surber Sampler on a pole, consisted of a 

 modified Turtox bottom net 10" deep with dimensions of 8" x 8" , a six-foot 

 wooden handle used to hold the net perpendicular to the current, and wire 

 frame 17" x 16" attached to the bottom lip of the net frame perpendicular 

 to the net opening in such a way that the wire frame rested on the stream 

 bottom. The area within the frame was 272 in 2 (0.175 m^) . When the area with- 

 in the frame was disturbed, bottom organisms were carried into the number 20 

 (0.70 mm) mesh net. Net material was added to each side of the wire frame 

 to minimize side washout of organisms. 



This technique can be used as lonq as the water is shallow enough to 

 wade. The bottom outlined by the frame is merely stirred with the foot. 

 This sampler was used at the Glendive and Intake sampling stations during 

 1975 only. Water depth, and current speed at six-tenths total depth, were 

 determined in the center of each sampling site. A timed (2-minute) kick 

 sample without the 17" x 16" frame was taken at many stations during 1974 

 in the Yellowstone and Tongue rivers to determine relative abundance of 

 organisms. 



A Water's round sampler was used to take six samples per month at ten 

 of the 20 sampling stations in the Yellowstone River from August to November 

 1975 The Water's sampler is 19.5 in (.495 m) in height and encloses an area 

 just'slightly less than one ft? (143.14 in2 or 0.093 m2) . The area to be 

 sampled, randomly selected, is approached from downstream. After forcing 

 the sampler into the bottom, the investigator reaches down through the open 

 top and stirs the bottom with his hand. Water current carries the orqamsms 

 into the trailing, 20-mesh net. All organisms were preserved in the field 

 in 70-percent ethyl alcohol. 



Hester-Dendy multiple-plate artificial samplers (Hester and Dendy 1962), 

 Fullner 1971, Parsons and Tatum 1974) were used occasionally during 1974 but 

 their use was discontinued when they proved to be unsatisfactorily colonized. 



In the laboratory, all organisms were nicked from bottom detritus and 

 gravel under a dissecting microscope. Immature invertebrates were identified 

 to genus and species (and, less commonly, only to family) using appropriate 

 taxonomic keys. Adult insects were used whenever possible to confirm species 

 identifications. Experts (identified on page 4 ) were consulted when 

 difficulties were encountered. 



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