40 



taken in mid-October near the completion of the first year's growth. • As a result, The age I 

 class fish in this study correspond more to Brown's 2 year age class. If this is the case 

 then the age I class sculpins in Libby Creek were smaller than Brown's estimate for the 2 

 year age class but the age class was similar to the 1 year age class. The smaller size in the 

 age I class nearing the completion of 2 years of growth could be due to a number of factors 

 affecting growth rates such as temperature differences between drainages, overcrowding, 

 lack of food resources, or selective predation on larger individuals none of which were 

 monitored in this study. 



Sampling Methodology 



The electroshocker, in combination with the D-net, was by far the most effective 

 method for sampling sculpins. However, this technique did have shortcomings. Sculpins 

 were often capable of eluding the electrical field unlike salmonids which were typically 

 immobilized by the electrical field or exhibited galvonotaxis. This difference was probably 

 due to physiological, morphological, and/or behavioral differences in these two groups. 

 Sculpins often escaped the field by burrowing into the substrate through the interstitial 

 spaces. The larger rocks probably deflected the electrical field to some degree. On 

 numerous occasions, sculpins were immobilized by the shocker but quickly darted away 

 when the power was turned off. Additional research should be conducted on the use of AC 

 power verses DC power to see if one power source is more effective than the other on 

 sculpins. 



Elctroshockers in combination with block nets are commonly used for obtaining 

 salmonid population estimates on fourth order streams and smaller. Will this same 

 methodology produce reliable results from which land managers can base decisions for 

 land-use in particular watersheds? Based on sampling efforts in this study and 



