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  • Title

    Habitat, hatcheries, and nonnative predators interact to affect juvenile salmon behavior and survival

    Lead University of California - Santa Cruz [UCSC]
    Description Chinook salmon are an iconic part of California’s environment and heritage, and important both economically and culturally. In the Sacramento River, the winter-run Chinook population is endangered, and there is strong interest in restoring these populations. To do so, resource managers need to better understand the pressures on wild populations. Predation by nonnative predators affects survival of young salmon but may also affect the behavior of salmon. Changes to salmon behavior also have costs but are not currently considered in management. Managers need information on how predators affect juvenile salmon behavior, how they might vary under different conditions, and how they scale up to affect populations.
    Science topics Chinook Salmon, Fishing
    Updated November 17, 2022
  • Title

    Consequences of Phragmites invasion for community function in Suisun Marsh

    Lead University of California - Davis [UC Davis]
    Description

    This project aims to quantify the impacts of common reed (Phragmites) invasion on community structure and ecosystem function during early stages of tidal restoration in wetlands. The study will focus on the Tule Red Tidal Restoration site in Suisun Marsh. The research aims to produce a conceptual model that will describe habitat structure, invertebrate communities, and predator use of wetlands affected by Phragmites invasion. The conceptual model resulting from this study will guide future predictions of wetland response to invasion and to develop mitigation strategies. Data collected will also support food web models and the understanding of invasive plants as stressors, as well as foster translational science to the management community.

    Science topics Invasive / non native species
    Updated February 28, 2025
  • Title

    Risk of fish predation within and across tidal wetland complexes

    Lead University of California - Davis [UC Davis]
    Description

    This study focuses on understanding how restored tidal wetlands with different physical configurations function as refuge and rearing habitat for fishes, including native and imperiled species such as delta smelt and juvenile Chinook salmon. This research will assess the spatial distribution of predation risk as it varies within and across tidal wetlands. The proposed research will generate a statistical model that helps predict predation outcomes from various restored tidal wetland designs and channel configurations. This will be a powerful tool for managers to forecast how proposed habitat restoration or water management actions may impact native fish populations.

    Science topics Tidal wetlands
    Updated February 27, 2025
  • Title

    Environmental geochemistry and tidal wetland support of pelagic food webs

    Lead University of California - Davis [UC Davis]
    Description

    This project aims to characterize and quantify where detrital material (decaying plant matter) originates within wetlands, the composition of that material, and how export of detrital particles occurs. This project will combine powerful characterization tools and techniques that scale from molecules to ecosystems to assess spatial and temporal trends in particle sources, species and composition. Because restoration in the Sacramento-San Joaquin Delta will fundamentally alter particle distribution and food availability for aquatic organisms, this study will inform habitat restoration efforts and the revival of native fish populations. The tools developed and adapted for this project may inform management response during extreme conditions and climate events by helping to identify areas that may act as refugia for species.

    Science topics Wetlands
    Updated March 11, 2025
  • Title

    Examining the relationship between Longfin Smelt and flow in the San Francisco Bay Delta

    Lead University of California - Berkeley [UC Berkeley]
    Description The number of longfin smelt in the San Francisco Estuary has been in decline for the past several decades. While decreased freshwater flow reaching the estuary has been identified as a contributing factor, the relationship between flow and smelt populations has proven complex and appears to be changing over time. This study examined how water flow affects longfin smelt populations across different habitats in the San Francisco Estuary, analyzing decades of monitoring data from state and federal agencies. The research explored both where smelt live in the estuary and how their populations change over time in response to varying water flows. The findings show that more freshwater flow generally helps smelt populations, especially young fish in shallow waters. However, this beneficial effect appears to be weakening over time in some areas, particularly in open waters away from the shore. This suggests that smelt may be adapting to changing conditions by moving to different parts of the estuary. To help protect this threatened species, conservation efforts may need to focus on both restoring natural water flows and improving habitat conditions throughout the estuary.
    Science topics Fish, Flows, Longfin Smelt, Zooplankton
    Updated February 27, 2025