Study of Wild Spring Chinook Salmon in the John Day River System, 1985 Final Report.

Abstract

A study of wild spring chinook salmon was conducted in the John Day River, Oregon: (1) recommend harvest regulations to achieve escapement goals in the John Day River; (2) recommend adtustments in timing of fish passage operations at Columbia River dams that will increase survival of John Day migrants; (3) recommend habitat or environmental improvements that will increase production of spring chinook salmon; (4) determine escapement goals for wild spring chinook salmon in the John Day River; and (5) recommend procedures for hatchery supplementation in the John Day River in the event it becomes necessary to artificially maintain the run of spring chinook salmon. Juveniles were captured as smolts during migration and as fingerlings during summer rearing. Juveniles were coded-wire tagged, and recoveries of tagged adults were used to assess contribution to ocean and Columbia River fisheries, timing of adult migrations through the Columbia River in relation to fishing seasons, and age and size of fish in fisheries. Scoop traps and seines were used to determine timing of smolt migrations through the John Day River. In addition, recoveries of tagged smolts at John Day Dam, The Dalles Dam, and Jones Beach were used to determine migration timing through the Columbia River. We examined freshwater life history of spring chinook salmon in the John Day River and related it to environmental factors. We looked at adult holding areas, spawning, incubation and emergence, fingerling rearing distribution, size and growth of juveniles and scales. Escapement goals fo the John Day River as well as reasons for declines in John Day stocks were determiend by using stock-recruitment analyses. Recommendations for hatchery supplementation in the John Day were based on results from other study objectives.