The most intensive monitoring was done in 1996 and 1997 by the graduate student. The abstract 

 from her Master's Thesis, completed in 1998, is shown in Appendix D. t 



It is encouraging to note the larger number of fry out migrating in 1997 than in 1996. These 

 small fish will be the basis for an adult population that will migrate back into Mill Creek to 

 spawn in 3-4 years, repeating the cycle and, hopefully, eventually reestablishing a suitable 

 spawning run offish into Mill Creek. In the past, there have been inadequate flows at the mouth 

 of the creek to allow fry to reach the Yellowstone River. It should be noted, however, that higher 

 flows have occurred naturally in Mill Creek in the last 2-3 years, which contributes substantially 

 to the success of spawning and out migration. The higher numbers of fry cannot be attributed 

 just to the water leases. 



6. Cedar Creek . The lease was first implemented in 1996. Monitoring has been done by both 

 FWP and the same graduate student working on Mill Creek. 



The Monitoring Plan for Cedar Creek requires three gages be installed to monitor flows. All 

 three gages were installed by the USGS prior to the 1996 irrigation season when the lease took 

 effect. The extremely high flows of spring runoff in 1996 damaged the gages and they had to be 

 reset and recalibrated after runoff was over. The monitoring effort was hindered by the high 

 flows but some data were obtained. There were some lapses in the 1.3 cfs minimum flow in the 

 water lease during the course of the irrigation season. However, 1996 served as a pilot 

 monitoring effort that was expected to be improved in 1 997. 



Cedar Creek experienced a large out migration of cutthroat fry in 1997. In the past, spawning 

 redds have been dewatered when flows dropped after spawning occurred. No redds were 

 dewatered in 1997. A total of 25,781 fiy were caught in traps as they were out migrating to the 

 Yellowstone River in 1997, compared to 13, 251 fry caught in 1996. Again, the high nimibers of 

 fiy cannot be entirely attributed to the water lease but it is, nevertheless, encoiuaging to see 

 improving spawning success. The abstract from the student's Master's Thesis, completed in 

 1 998, is shown in Appendix D. 



7. Tin Cup Creek . The lease was first implemented in 1996. Monitoring is done by the local 

 fisheries biologist. Data on rainbow trout spawning and reproduction was collected in 1992, 

 1993 and 1994, prior to implementing the lease. One year of data has been collected since the 

 lease (1997). The 1997 data show the number of rainbow fry leaving the creek is not an 

 improvement over pre-lease years. Howevt., sampling rainbow fiy is difficult since they leave 

 the creek before high flows are completed. Sampling efficiency is variable depending on flow 

 conditions and the intensity of sampling has an effect on estimating numbers of fiy. Further 

 monitoring will be needed before firm conclusions can be made about the benefits of the lease to 

 rainbow trout. * .. 



Cutthroat trout may also migrate into Tin Cup Creek to spawn, but we have no data either 

 previous to or since the lease to compare, largely because cutthroat spawn during higher flows 



A-13 



