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."\, :[7' ~~... Colorado River again this year. Additional research this year will be focusing on the formation and location of backwaters in the critical Geographic Information System reaches. The dam releases will return to normal summer interim flow operations after the photography is completed. ~~ '~ Riparian Ecosystem. With the movement of the sediment back towards the channel, many of the backwaters, eddies and return channels that had been ' -, the locations of small marshes and localized habitats are changing. With the increase in sediment and the continual movement of the riparian vegetation from the 30,000 cfs zone to the 20,000 cfs interim flow cap level, many of the marshes are loosing their aquatic flavor and becoming more terrestrial in nature. We are very interested in the recolonization rate and use of the marshes-turned-riparian areas by neotropical birds and reptiles. ':1 ~ Studies this winter have again focused on the use of the Nankoweap Canyon area by the wintering Bald Eagles, Halieaeetus leucocephalus. This winter Nankoweap Creek turned cold early in the winter and the number of spawning Rainbow Trout, Onchorynchus mykis. never reached the capacity level necessary to support large numbers of birds. Early returns from the eagle survey indicate that the wintering birds spread themselves out through the Canyon and were more isolated in their locations. It appears that the numbers of spawning trout are a large determinant on the number of birds that the area supports. " I ~ .~,' I ~ !~~ :-.:. Several trips this spring will continue to document the migration of the riparian vegetation down to the 20,000 cfs Interim Flow maximum flow level. Additional work begins this spring on the food and habitat studies on the neotropical migrants that utilize the nearshore riparian zone. :"1 -- ,-' Aquatic Resources . Native Fish: The native fish studies in the Grand Canyon have been relatively dormant the past three months as the researchers have been spending time focusing on the interpretation of their 1993 results and beginning work on their final reports. Much of the effort has focused on following the progress and recruitment of the 1993 humpback chub, .Qili Wha. year class. As of this writing the adult chubs are beginning to mass in the vicinity of the Little Colorado River awaiting the cues to initiate spawning. ..:~ r: '~ " ..~ < '. , Some initial findings that will continue to be evaluated and verified during the 1994 interim flow work include: 1. The use of the spring area in the River Mile 30 area. Evidence was found last year that some spawning may be occurring in the areas around the warm water springs. 2. Utilization of near shore habitats by juvenile and young-of-year fish. 3. Fidelity of specific locations and habitat types by adult chubs 4. Population demographics of other native fish species Non.Native Fish: Studies continue on the trout and other non