Yakima River Spring Chinook Enhancement Study, 1984 Annual Report.

This study develops data to present management alternatives for Yakima River spring chinook. The first objective is to determine the distribution, abundance and survival of wild Yakima River spring chinook. Naturally produced populations will be studied to determine if these runs can be sustained in the face of present harvest and environmental conditions. This information will be gathered through spawning ground surveys, counting of adults at Prosser and Roza fish ladders, and through monitoring the tribal dipnet fishery. Concurrent studies will examine potential habitat limitations within the basin. Presently, survival to emergence studies, in conjunction with substrate quality analysis is being undertaken. Water temperature is monitored throughout the basin, and seining takes place monthly to evaluate distribution and abundance. The outcome of this phase of the investigation is to determine an effective manner for introducing hatchery stocks that minimize the impacts on the wild population. The second objective of this study is to determine relative effectiveness of different methods of hatchery supplementation