BIOLOGY OF CHI^DOK AND BLUEBACK SALM3N AND STEELHEAD 

 IN THE WENATCHEE RIVER SYSTEM 



by 



Robert R. French and Roy J. Wahle 



U. S. Fish and Wildlife Service 



Seattle, Washington 



ABSTRACT 



The Wenatchee River contains important runs of salmon and steelhead trout. 

 Peak yearly adult counts at Tumwater Dam for 1955-1957 were 52,000 blueback salmon, 

 5,200 Chinook salmon, and 850 steelhead trout. Approximate peaks of migration 

 occurred in early August for blueback, the middle of June to late July for chinook, 

 and the end of April and late August for steelhead. 



Each species and race had its characteristic spavming area. Blueback chose 

 the tributaries of Lake Wenatchee; spring chinook, the tributaries and upper reaches 

 of the Wenatchee River; and summer chinook spawned exclusively in the main Wenatchee 

 River. 



Downstream migrating young fish were trapped at Tumwater Dam from April to 

 November. The peak of blueback seaward migration occurs in early May prior to the 

 high water season. Chinook and steelhead migrate in the spring and throughout summer 

 and fall months. Migration peaks for chinook were in early May and in mid-September 

 and mid-October. For steelhead trout, peaks occurred in the spring and in mid-August 

 and mid-September. The majority of blueback migrate in their second year; chinook 

 and steelhead trout migrate in both their first and second years. 



INTRODUCTION 



The Wenatchee River and its tributaries 

 have long provided spawning and rearing areas 

 for blueback salmon ( Oncorhynchus nerka ), 

 chinook salmon ( Oncorhynchus tshawytscha ) , 

 and steelhead trout ( Sal mo gairdnerii) . Sil- 

 ver salmon ( Oncorhynchus kisutch ) were once 

 abundant in this watershed, but very few are 

 found in this area at the present time. In 

 particular, Lake Wenatchee and its tributar- 

 ies now provide one of the two major spawn- 

 ing and rearing areas for blueback salmon 

 remaining in the Columbia River system. 



Grand Coulee Dam, completed in 1938, 

 blocked off approximately 1,140 lineal miles 

 of salmon spawning eind rearing areas in the 

 upper Columbia River system. In order to 

 salvage salmonoid fishes heading for the now 

 inaccessible areas above Grand Coulee Dam, 

 the U. S. Fish and Wildlife Service trapped 

 all adult migrating fish at Rock Island Dam 

 and hauled them to the river systems tribu- 



tary to the Columbia River below Grand 

 Coulee Dam.i' The Wenatchee River system, 

 figure 1, was chosen as one of the systems 

 to which fish were transplanted. This 

 system contains approximately 130 lineal 

 miles of spawning cind rearing areas of the 

 340 miles found in the systems between Rock 

 Island and Chief Joseph Dams. In about 1952 

 Chief Joseph Dam blocked off approximately 

 60 miles of stream between it and Grand 

 Coulee dam. 



Chelan County Public Utility District 

 No. 1 is studying the feasibility of a 

 dam or dams for power production in the 



_!/ Fish, Frederic F., and Mitchell G. 



Hanavan, 1948. A report upon the Grand 

 Coulee fish-maintenance project 1939- 

 1947. U. S. Fish and Wildlife Service, 

 Special Scientific Report — Fisheries 

 No. 55, November, 63 pp. 



