Movements of Chinook Salmon throughout Puget Sound

Traditionally Salmon are assumed to migrate from spawning to ocean feeding grounds and then return.  However, recent studies have demonstrated a wide diversity in their migratory behavior.  In Puget Sound, Washington, Chinook salmon exhibit a spectrum of spatial and temporal migratory behavior ranging from individuals that migrate to the ocean (ocean-migrants) to those that spend their entire lives in inland bodies of water (residents). We used acoustic telemetry to characterize both large- and fine- scale movements of individual residents and examined how a myriad of factors (including size and hatchery- versus naturally-produced status) relates to this movement. This presentation incorporates results from 100 Chinook salmon tagged in Central and North Puget Sound. Although these fish were believed to be residents (based on size and timing), we found that about 25% were ocean migrants. Further, 62% of the detections outside of Puget Sound were of presumed resident fish (based on size and time collected) that were tagged/released in central Puget Sound. Many of these fish returned to Puget Sound instead of continuing to the Ocean. 85% of detections in Central Puget Sound were from fish tagged/released in that general area.  Fish tagged in Central and North Puget Sound both migrated to the Whidbey basin, an area between the two targeted tagging areas.  Surprisingly 73% of detections in Northern Puget Sound were from fish tagged in the Central basin of Puget Sound, and only 14% of all North Puget Sound detections were attributed to fish tagged/ released in that general vicinity. These findings are giving us important insight into habitat use, distribution, and survival. Gaining understanding of this continuum of migratory behaviors is important when considering the role of these fish in both recreational and commercial fisheries throughout the Pacific Northwest.