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Check out the IEP Calendar for upcoming Project Work Team, Stakeholder Group meetings and other IEP related events!

  • No scheduled events for June.

Other Events or News

  • San Francisco Estuary Partnership (SFEP) launches Estuary Youth Council
    • In 2023, the SFEP kicked off a new youth-centered program called the Estuary Youth Council. This is a pilot leadership development program developed in collaboration with Mycelium Youth Network, Nuestra Casa, and Restore the Delta. The Estuary Youth Council will give young people, especially youth from underserved communities, opportunities to advise environmental managers with youth-centered perspectives, priorities, and concerns in the restoration and adaptation of the San Francisco Estuary as well as offer professional development.
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Featured Survey

  • Delta Juvenile Fish Monitoring Program
    As the weather improves and warms through the spring, many of our native and non-native fish become more active, with many species growing into the juvenile life stage and showing much broader ranges of movement within the San Francisco Estuary. The Delta Juvenile Fish Monitoring Program incorporates several survey techniques and analytical approaches to develop an appreciation for the abundance of these fishes and how they move through our Delta and Estuary. Many of our most common and important commercial species of fishes are found using this gear, and their populations later in the year frequently show strong dependence to how well these juvenile fish fare during the months before our aquatic habitats become warm and lower-flowing.

Featured Publications

  • A new Open-File report on Green Sturgeon seasonal movement is available from the USGS from Hansen and others. The report suggests tagged fish move downstream in the fall and winter concurrent with increasing flows in the Sacramento River. The citation and website are available as: Hansen, A.C., Burdick, S.M., Johnson, R.P., Chase, R.D., and Thomas, M.J., 2024, Adult green sturgeon (Acipenser medirostris) movements in the Sacramento–San Joaquin River Delta, California, December 2020–January 2023: U.S. Geological Survey Open-File Report 2024–1025, 17 p.,
  • Zillig and 5 colleagues also have interesting results regarding Green Sturgeon in their recent publication in Conservation Physiology Effects of acclimation temperature and feed restriction on the metabolic performance of green sturgeon. Interactions with management strategies with those of Green Sturgeon are an implication of this research, and the authors state “The sympatry of threatened green sturgeon with endangered salmonids produces a conservation conflict, such that cold-water releases for the conservation of at-risk salmonids may constrain the metabolic performance of juvenile green sturgeon. Understanding the impacts of environmental conditions (e.g. temperature, dissolved oxygen) on ecological interactions of green sturgeon will be necessary to determine the influence of salmonid-focused management.”
  • An integrated population model and sensitivity assessment for a data poor population of green sturgeon is the subject of an additional peer-reviewed article on the species this month appearing in the Canadian Journal of Fisheries and Aquatic Sciences. From the abstract: “We combined spawning census, growth, and demographic data for the southern population of green sturgeon to build a population size and trajectory estimate. We generated a distribution of population size estimates and trajectories reflecting uncertainty from multiple sources. We then propagate these estimates through a demographic model to assess the potential impact of fishing bycatch. Our model suggests the population is below the recovery goal of 3,000 adults.”
  • Sturgeon receive more attention (White Sturgeon this time) in an article this past winter from the Journal of Fish and Wildlife Management from Ulaski and co-authors. Creativity in methods used for analysis is the subject of their publication cited here: Ulaski ME, McCormick JL, Quist ME, Jackson ZJ. 2023. Leveraging angler effort to inform fisheries management: using harvest and harvest rate to estimate abundance of white sturgeon. Journal of Fish and Wildlife Management 14(2):324–336; e1944-687X.
  • A NOAA Technical Memorandum from the National Marine Fisheries Service is available from Hendrix and colleagues regarding the Life Cycle Modeling Framework for Chinook Salmon spawning in the Sacramento River. From the paper: “Here, we introduce the Sacramento River Chinook salmon life cycle model (SRCLCM), an LCM framework for winter-run (listed as endangered under the federal Endangered Species Act) and fall-run Chinook salmon spawning in the Sacramento River. The SRCLCM is a network of interconnected models, and relies on flow and water temperature data, hydraulic models, habitat capacity models, and an early life-history model that uses relationships linking in-river water temperature and/or streamflow to smolt production and ocean indicators to predict early marine survival rates and adult abundance. In this document, we describe the framework of the SRCLCM, including the model structure, the stage transition equations, and the required data inputs for the SRCLCM.”
  • Polansky, Mitchell, and Nobriga weigh in with another important paper using a life cycle approach to understand Delta Smelt habitat needs. Their contributed paper, appearing in Conservation Science and Practice, suggests: “models are used to quantify drivers of growth rate variation over 30 years. Several complimentary sensitivity analyses indicated freshwater outflow to the estuary during summer had the largest potential to change population growth. Multiple habitat metrics (e.g., food availability, temperature) influencing recruitment and life stage specific survival rates across different seasons interacted in nonlinear ways to determine habitat conditions and water management targets associated with positive population growth. We discuss the implications for freshwater management, Delta Smelt conservation, and the challenges climate change poses for co-implementation of these two societal priorities.”
  • Managing a cyanobacteria harmful algae bloom “hotspot” in the Sacramento – San Joaquin Delta, California is the title of a research article recently published in the Journal of Environmental Management by Ellen Preece and 5 colleagues. From the abstract: “Cyanobacterial harmful algal blooms (CHABs) have become a persistent seasonal problem in the upper San Francisco Estuary, California also known as the Sacramento-San Joaquin Delta (Delta). The Delta is comprised of a complex network of open water bodies, channels, and sloughs. The terminus of the Stockton Channel is an area identified as a CHAB “hotspot.” As CHABs increase in severity, there is an urgent need to better understand CHAB drivers to identify and implement mitigation measures that can be used in an estuarine complex like the Delta.”
  • Estuaries and Coasts has printed a synthesis article from several local researchers led by Matthew Young from the USGS. Young and Colleagues report on [T]he influence of time, tide, and place on fine-scale nekton distribution: insights from the San Francisco Estuary. The authors discuss: “Tidal phase and turbidity concentration influenced vertical and lateral distributions for some species at certain locations. Although infrequently encountered, we documented associations of longfin smelt with the lower water column and shoal habitats, with some evidence for upward vertical shifts in low light conditions brought about by nightfall or elevated turbidity. Observed habitat associations provide insight into how interacting geophysical and environmental factors may influence the distribution of nekton and thus the vulnerability of individual species to detection by sampling gears.”
  • Dr. Young also published an article in Frontiers in Marine Science titled Variability in coastal habitat for the Longfin Smelt Spirinchus thaleichthys in the northeastern Pacific Ocean. He and colleagues from the Northwest Fisheries Science Center discuss “coastal observations from numerous sources to estimate the range-wide coastal marine distribution of Longfin Smelt and assess habitat factors affecting distribution in the northeast Pacific Ocean. Based on maximum entropy species distribution models, Longfin Smelt distribution was correlated with depth, distance from the nearest estuary, sea surface temperature, and sea surface chlorophyll.”
  • Bergamaschi and 9 colleagues published an important Scientific Investigations Report from the United States Geological Survey. “This study examined the abundance and distribution of nutrients and phytoplankton in the tidal aquatic environments of the Sacramento–San Joaquin Delta (Delta) and Suisun Bay, comprising three spatial surveys conducted in May, July, and October of 2018 that used continuous underway high frequency sampling and measurements onboard a high-speed boat to characterize spatial variation across the extent of the Delta. The method used involves simultaneously collecting information about the concentration and spatial distribution of all major nutrient forms with analogous information about the major classes of phytoplankton and associated water-quality conditions. The results showed substantial variation across space and time, providing an unprecedented snapshot of the dynamic environmental processes that shape the ways nutrients interact with and affect aquatic habitats in the Delta.”

Featured Dataset Publications

Featured Websites

  • Using Genetic Identification to Find Spring-run Salmon and More
    Using genetic information and material to identify runs of Chinook Salmon more definitively is the subject of a recent website update from our colleagues at the Department of Water Resources. These techniques are gaining more and more use in our work managing the various fisheries and aquatic resources in the San Francisco Estuary. Find this article and more on the DWR Updates Blog.
  • Frontiers for Young Minds
    Where the river meets the ocean - Stories from San Francisco Estuary