Factors associated with Chinook and coho marine survival variability

Investigators: Neala Kendall (WDFW), Mike Haggerty (Mike Haggerty Consulting), and Mike Crewson (The Tulalip Tribes of WA)

Previous SSMSP studies showed that Chinook and coho marine survival patterns vary greatly over time and space, that certain environmental indicators are better associated with these marine survival trends, that survival may be density dependent, and that these relationships vary over time. This project will further these analyses by examining if and how hatchery- and natural-origin Salish Sea, coastal Washington and British Columbia, and lower Columbia River Chinook and coho salmon marine survival trends vary in association with the presence of juvenile pink salmon in even and odd years across time and space and how Chinook and coho marine survival over different time periods relates to a variety of indicators including regime shifts and strong climactic events such as El Niño/La Niña, predator abundance, zooplankton abundance, forage fish abundance, ecological interactions with marine nekton, presence/absence of pink salmon, abundance of other species of salmon (including hatchery-origin stocks), contaminant levels (e.g., PCBs and DDTs), and streamflow. Finally, the project team will look for different stanzas in the relationship between Chinook and coho marine survival associated with the numbers of juveniles released (i.e., density dependent survival). With this information, we will better understand variation in Chinook and coho salmon marine survival and how we can communicate these changes.