Contribution of Lagoon-Rearing Juvenile Chinook Salmon to Adult Spawning Population in the Mattole River

Project Number
Project Date Range
Funding Agency
National Oceanic and Atmospheric Administration (NOAA)
Focus Area(s)
Resilient Coastal Communities and Economies




This project will analyze scale morphometrics and otolith microchemistry to determine which juvenile Chinook life history strategies (lagoon or ocean rearing) are represented in the return adult spawning population on the Mattole River. 



Unencumbered by dams, the Mattole River is one of the last coastal watersheds in California that hosts a population of wild Chinook salmon without hatchery influence. As recently as the 1960s, the Mattole River supported spawning runs of Chinook salmon, but the populations have seen a steep decline in the last several decades, in part due to logging, roadbuilding, agricultural development and more. Thus, it is critical to understand how juvenile Chinook behavior and survival relates to adult population sizes.

This project will evaluate the life history patterns and age of returning adult Chinook (between 2005-2024) to the Mattole River by examining the microchemistry and patterns in adult scales and otoliths (ear bones). The researchers will assess whether certain juvenile life history strategies or environmental factors (e.g., temperature, flow) lead to a greater chance of surviving to adulthood by returning to reproduce in the Mattole River. 

Knowledge gained from this study will fill a gap in basic understanding of the Mattole lagoon and its rearing capacity, inform adaptive management decisions and provide insight to neighboring coastal watersheds that may begin to experience annual sandbars as a result of climate change. The intention of this research is to improve upon and contribute to the understanding of federally listed Chinook salmon with the hope that ultimately, they will thrive again in California.

Community Mentor: Nathan Queener (Mattole Salmon Group)


Principal Investigators
Darren Ward
Cal Poly Humboldt
Co-principal Investigators
Emma Held
Cal Poly Humboldt