Sacramento River winter-run Chinook salmon cohort reconstruction – data and code

Maturation schedules shape a population’s age structure and influence productivity and exposure to fishing. Fish cultivated and raised in artificial environments like hatcheries may mature at different ages compared to their natural-origin counterparts. We evaluated whether endangered Sacramento River winter-run Chinook salmon (Oncorhynchus tshawytscha) produced in a conservation hatchery had different maturation schedules compared to natural-origin fish, and how differences affected their exposure to, and impact from, the ocean salmon fishery. Using coded-wire tags collected from hatchery fish in the ocean and in-river fisheries and on the spawning grounds, and scales collected from natural-origin spawner carcasses, we reconstructed the life history of hatchery and natural-origin cohorts from 2002–2015 brood years. Hatchery fish had similar age-2 maturation rates but higher age-3 maturation rates compared to natural-origin fish, resulting in fewer age-4 individuals and an overall more ...