Modeling the diversity of life history, through growth and development, in Snake River Chinook salmon using an Integral Projection Model framework

As climate change shifts temperatures, it is impacting the phenology of species with temperature-dependent growth. One such species is wild Chinook salmon (Oncorhynchus tshawytscha) in the Idaho Snake River Basin. Chinook salmon life history is complex, their growth and movement heavily influenced by temperature and food availability. In order to predict the impact of climate change on juvenile Chinook salmon life history, I developed a temperature-dependent integral projection model to evaluate potential freshwater growth and development, tracking salmon from spawning to smolt outmigration. After eggs emerge, juveniles follow one of two alternative life history strategies, either overwintering in their natal tributary or downriver in mainstem reaches, each with a distinct temperature regime. Both strategies culminate in spring outmigration in the Snake River. The model predicts the size of juvenile Chinook salmon through time, allowing comparison with observed size distributions. Furthermore, the model illustrates variation in smolt size intra- and inter-annually, and the proportion of fish that followed a particular life history strategy. Initial results show the model is accurately predicting within the range of observed smolt sizes, even with the relatively simple set of parameters being used. The computational efficiency of an integral projection model is well suited for use in large-scale simulations, including predicting distributions under many different climate scenarios.

Presentation Preference: Oral

Primary Presenter: Grace Veenstra, University of Alaska Fairbanks (gveenstra.ak@gmail.com)

Authors:

Grace Veenstra, University of Alaska Fairbanks  (gveenstra.ak@gmail.com)

Lisa Crozier, Northwest Fisheries Science Center, NOAA  (lisa.crozier@noaa.gov)