Yakima River Spring Chinook Enhancement Study. Fisheries Resource Management, Yakima Indian Nation. Annual Report, 1983

摘要

The purpose was to evaluate enhancement methodologies that can be used to rebuild runs of spring chinook to the Yakima River system. In January, 1983, 100,000 fish raised at Leavenworth National Fish Hatchery were transported to Nile Springs Rearing Ponds on the Naches River. These fish were allowed a volitional release as smolts in April. An additional 100,000 smolts were transported from Leavenworth Hatchery in April and immediately released to the Upper Yakima River. Relative survival of smolts from their points of release to a trap at Prosser (RM48) was 1.69:1 for fish from Nile Springs, versus the trucked smolts. The fish from Nile Springs arrived at Prosser and McNary Dam approximately 1 week earlier than the transported fish. To better determine the magnitude and location of releases, distribution and abundance studies were undertaken. There is a decrease in abundance from upstream areas over time, indicating a general downstream movement. In the Naches System, the lower Naches River is heavily utilized by juvenile spring chinook during the early summer. A preliminary study evaluated physical limitations of production. On a single evening 67 fish were killed on diversion screens at Chandler Canal. This constituted 5.7% of the wild spring chinook entering the canal and 8.2% of the fall chinook. The larger hatchery spring chinook sustained a 2.3% loss. Adult returns resulted in 443 redds in the Yakima System, with 360 in the Yakima River and 83 in the Naches System. (ERA citation 11:052107)