Studies on the Life History of Alsea River Steelhead

Abstract

A comprehensive life history study of the steelhead trout (Salmo gairdneri gairdneri) was initiated in 1954 by the Oregon Cooperative Wildlife Research Unit at the request of the Oregon State Game Commission, the agency most concerned with management of the species in the state. The initial phase of the study involved analysis of steelhead scale samples secured from drainages throughout Oregon (Bali, 1957). Since this work was general in scope, it was desirable in the present study that a particular stream be investigated. The Alsea River was chosen for this purpose, because it was typical of Oregon coastal streams and because of its proximity to Oregon State College, where the Research Unit is based. The Alsea River rises on the west slope of the Coast Range and flows into Alsea Bay near Waldport. The area of the drainage basin (Fig. 1) is about 450 square miles, and the terrain therein is generally rough and steep, with little flat land other than small portions found intermittently along the main river. Some of the forest lands are newly logged, some are covered with hardwoods, and others are in some stage of coniferous growth. The river estuary is about 10 miles in length and enters the Pacific Ocean at Waldport. The lower portion of the bay is quite saline, but upper reaches grade into fresh water toward the head of the tidal influence. No closure of the river mouth