Migrations of Salmon and Trout in Puget Sound: New Approaches to Old Questions

Abstract

The migrations of salmon and trout are an integral part of their basic biology and are also important for their conservation because migrations define critical habitat and control patterns of fishery exploitation. Decades of tagging with a variety of techniques has yielded many insights but the ability to follow individual fish is of special value. This presentation describes a collaborative project involving many entities in the Puget Sound region, using ultrasonic tracking to describe the movements of individual salmon and trout. Tracking includes species that differ in their hypothesized reliance on Puget Sound as habitat: steelhead (believed to migrate directly to the ocean as smolts), Chinook and coho salmon (some infividuals reside in Puget Sound and other inland waters whereas other migrate to the coastal ocean), and cutthroat trout and bull trout (believed to remain near their natal streams during their period in marine waters). Examples of the kinds of data are presented to illutrate some of the patterns that we are seeing, including diel activity rhthms, home range, and exploratory behavior.