3 1 



The electroshocker was more effective at immobilizing salmonid species than sculpins. 

 All sculpin species encountered in this study were generally capable of escaping the 

 electrical field whereas salmonids would gravitate toward the positive electrode 

 (galvanotaxis). Only the larger sculpins (usually torrents and some shortheads) displayed 

 galvanotaxis but on a limited basis. 



Diagonal transects using D-nets appeared to be an effective sampling technique in riffles 

 containing small rubble and high sculpin densities. This method was used at Upper Ford 

 on the main Yaak and on Libby Creek near the fish hatchery. Three 1 5 foot transects 

 yielded 3 sculpins per pass at Upper Ford. Two similar transects at Libby Creek netted 2 

 sculpins per pass. Current velocities typically found in riffles were a prerequisite for this 

 technique to be effective. Sculpins disturbed while shuffling the substrate were swept into 

 the net before orienting themselves in the current. Limited efforts in runs revealed that this 

 technique would not be practical in habitat where current velocities tend to be slower. 



The kick-screen proved to be an ineffective method for sampling sculpins. The kick- 

 screen was also used at Upper Ford on the Main Yaak (T36N R31W sect. 6 SE). It 

 appeared that sculpins swept against the screen by the stream current were able to escape 

 before the screen was pulled from the water by re-orienting themselves and swimming 

 against the current. Modifications of the screen such as using mesh cloth with a deep 

 pocket rather than the straight metal screen might make this a more effective sampling 

 method. 



Minnow traps were ineffective at catching sculpins. The traps were placed at the Libby 

 Creek site near the fish hatchery (T30N R31W sect. 36 SW). No sculpins migrated into 

 the traps on any sampling interval (2, 4, 6, and 12 hours). The traps were disassembled 

 after running the experiment for 12 hours. It was apparent that some emigration of benthic 



