Science activity

Science activity #53616, updated 1 February 2024

Monitoring Sacramento River winter-run Chinook salmon life history diversity, growth, and habitat use among varying hydroclimatic regimes

Description / purpose

Sacramento River winter-run Chinook salmon have been endangered since 1994. Historically, the fish spawned during summer in cool tributaries upstream of Sacramento, but dams have limited spawning habitat to a small reach of the river. Today, survival of their offspring is heavily dependent on cool summer water releases from reservoirs, which also provide critical water supplies for irrigation, municipal, and industrial needs, as well as providing flood control and hydropower generation. During drought, this can lead to difficult management decisions. Understanding how winter run Chinook salmon respond to drought and water temperature is therefore vital to the management of this endangered population. This project tackled two outstanding questions about winter-run salmon ecology. The first was how winter-run Chinook use different rearing habitats during drought and non-drought periods, and the second was to explore which habitats provide enhanced growth during drought and non-drought periods. To answer these questions, UC Berkeley post-doc Pedro Morais used isotopic analysis of otoliths, or fish ear bones, which grow continuously throughout their lives and therefore carry a record of their environment and growth. Using otoliths, researchers can reconstruct details of fishes’ lives, including water temperature and migration patterns.

Linked science activities

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  • (Left) Juvenile salmon, shown, use different rearing habitats on the freshwater landscape prior to seaward migration. Image by Rachel Johnson, NOAA Fisheries; (Right) Photograph of a sectioned otolith from a juvenile Chinook salmon showing the daily increments that provide information on fish age and growth (much like tree rings). The chemical composition of the otolith is used to reconstruct fish growth and movement into different habitats as the salmon migrate from where they were born to the ocean. Image


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Activity status

  • 1 Awarded / Initiating (2017)
  • 2 In progress / Ongoing
  • 3 Complete

Funding summary

Total allocated funding: $259,288

Label Value
Contract # or labor code None
Implementing organization University of California - Berkeley [UC Berkeley]
Funding organization Delta Stewardship Council - Delta Science Program
Funding Source Not provided
Date of award 2017-02-01
Date of fiscal year-end Not provided
Total award amount $259,288
State type of obligation Not provided
Federal type of obligation Not provided
Reimbursability Not provided
Procurement mechanism Not provided


Delta regions

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