APPENDIX D 



ABSTRACT 



In 1989 the Montana Legislature passed House Bill 707, allowing Montana Fish, 

 Wildlife and Parks to lease water rights to benefit fisheries. The first water leases on 

 tributaries of the upper Yellowstone River were finalized in 1992 on Mill Creek, and in 

 1993 on Cedar Creek. The leases provide instream flows from May to October in an 

 attempt to reestablish Yellowstone cutthroat trout (Oncorhynchus clarki bouveri) 

 spawming runs. This study evaluated the existing leases' effect on fry recruitment. 

 Recruitment to the Yellowstone River was measured in 1996 and 1997 on four 

 tributaries: Locke, Mill, Cedar, and Mol Heron creeks. Since Yellowstone cutthroat trout 

 fiy move out of their natal tributaries soon after emergence, outmigration was monitored 

 using traps located near the mouth of each stream. More fiy were captured in 1997 than 

 in 1996 in all but Mol Heron Creek. Mill Creek had the greatest percent increase in fiy 

 captured (4000%), followed by Locke Creek (300%), and Cedar Creek (200%). The 

 lease on Cedar Creek prevented extended pre-emergence dewatering in 1 996. The 

 instream flow lease in Mill Creek was critical during fry outmigration in 1 996, but not in 

 1997 because of unusually high discharge. Fot sampling protocol development, fry 

 outmigration was broken into three stages based on observed patterns; the ascending 

 limb, peak region and descending limb. Three pattern-based, and three systematic 

 sampling protocols were evaluated in terms of their ability to provide a reliable estimate 

 of fry outmigration with a minimum number of sample days. Mean estimates from four 

 replications of each of the three pattern-based protocols were less variable and sampled 

 fewer days than those from the three systematic protocols. Pattern-based protocol A, 

 which concentrated sampling during the peak region of fry outmigration, and minimally 

 sampled the descending limb, was chosen as the best protocol for all four streams because 

 of the consistently narrow 95% confidence interval for its estimates, and was 

 recommended to Montana Fish, Wildlife and Parks for adoption. Based on my results, 

 other water leases should be pursued on creeks where dewatering is affecting fry 

 recruitment, and fiy outmigration should be monitored periodically to evaluate each 

 lease's effectiveness. 



A-23 



