EIP 1970-2020


IEP News

Breaking News!

  • NEW The Predation Project Work Team (PWT) has completed the launch of its Predation Project Tracker. You can view the current list of predation-related projects in the region by visiting the Predation PWT web page and downloading the Predation Project Tracker (Excel file). Additional projects can be voluntarily shared using their online project submission form, which is also listed on the web page.
  • New IEP Historical Metadata Template (PDF) document has been released by the IEP Data Publication Working Group.
    • The purpose of the document is to improve metadata documentation practices of our IEP surveys. The document can be found on the DUWG web page under the Templates and Guidelines section.
  • New IEP Digital Datasheet Best Practices (PDF) document has been released by the IEP Data Utilization Work Group's QA Subcommittee.
    • The purpose of the document is to provide guidance and recommendations on development and use of digital data sheets for staff in the IEP. The document can be found on the DUWG web page under the Templates and Guidelines section.

Featured Survey

  • Fall MidWater Trawl:
    • As one of the more well-known surveys, the Fall Midwater Trawl was established in 1967 to track trends in abundance and distribution of young Striped Bass.  It has come to be associated with Delta Smelt distribution and population index over the years, the survey catches many pelagic species in its extensive survey range.
    • The FMWT samples 122 stations each month from September to December and a subset of these data is used to calculate an annual abundance index. These 122 stations range from San Pablo Bay upstream to Stockton on the San Joaquin River, Hood on the Sacramento River, and the Sacramento Deep Water Ship Channel. Sampling takes approximately 10 days per month to complete. Historically, FMWT sampling occasionally began as early as July (1972) or August (1968-1973, 1993-1994, 1996-1997) and sometimes continued past December to March (1968-1973, 1978, 1991-2001) or beyond (1992-1995).

Featured Publications

  • New William Satterthwaite at NOAA’s Southwest Fishery Science Center has published a research article in San Francisco Estuary and Watershed Science developing An approach to defining a Sacramento River Fall Chinook escapement objective considering natural production, hatcheries, and risk tolerance. In this impressive manuscript the author “offer[s] a modeling framework for integrating consideration of established hatchery spawning goals, natural-area production or habitat capacities measured at varying spatial scales, and policy decisions about what fraction of potential natural production is desired along with risk tolerance. The model allows evaluating how likely a potential escapement goal (measured at the currently-used scale of fall-run adults returning to both hatcheries and natural areas throughout the Sacramento River basin) is both to meet hatchery goals and to produce at least a specified fraction of potential natural production.”
  • New  Guzman and others have published an article in Earth’s Future entitled Future Marsh Evolution Due to Tidal Changes Induced by Human Adaptation to Seal Level Rise, through changes in vegetation patterns across the landscape. In their useful Plain Language Summary, they write: “Human adaptation to sea level rise can involve physically modifying shorelines, such as building sea walls (shoreline hardening) or removing them (shoreline softening). Research has shown that these actions can sometimes change the tidal range across a region, which can also be changed by natural factors. Coastal marshes are sensitive to tidal range because their ecology is driven by tidal flooding. We investigated how changes in tidal range and sea level rise could impact a marsh located in San Francisco Bay, California, USA by modeling multiple scenarios from 2010 to 2100.”
  • New  Experimental studies by Tsai and colleagues of cultured and wild Delta Smelt spawning behavior at the University of California at Davis Fish Conservation and Culture Laboratory have resulted in a Research Publication in San Francisco Estuary and Watershed Science. A qualitative comparison of spawning behavior between cultured and wild Delta Smelt (Hypomesus transpacifcus) describes how “comparisons between wild and cultured populations are invaluable for informing conservation measures, though opportunities to do so may be rare. In this study, we asked whether spawning between and among wild and cultured Delta Smelt varies in terms of behavior or resulting egg fertilization success.”
  • New  Maintaining fish population genetic diversity (as effective population size, or Ne) in the face of increased hatchery production is the subject a recent article from LaCava and 9 colleagues found in the Transactions of the American Fisheries Society. Crossing experiments to investigate strategies for population-related management of Delta Smelt spawning are of prime interest as the Bay-Delta community considers conservation measures for this highly imperiled endangered fish.
  • New  Identification of key regional areas for supporting bird conservation is the focus of an article in San Francisco Estuary and Watershed Science written by Dybala and collaborators. As part of Priority bird conservation areas in California’s Sacramento-San Joaquin Delta the authors found “that over 60% of the Priority Bird Conservation Areas are not currently protected, indicating a vulnerability to changes in land cover or land use. We recommend advancing strategies for bird conservation in the Delta by developing more specific objectives and priorities, extending these analyses to include other bird species, and planning to mitigate the loss of Priority Bird Conservation Areas where they are most vulnerable to land cover change.
  • New  Liver glycogen as a sensitive indicator of food limitation in Delta Smelt is an article published in Estuaries and Coasts from a group of researchers led by Dhayalan and others. In what may mark the establishment of a powerful new monitoring tool, this research “identified a biomarker capable of rapidly detecting food limitation in the imperiled Delta Smelt (Hypomesus transpacificus), a pelagic fish endemic to the San Francisco Estuary (SFE). […] When applied to hatchery-released Delta Smelt collected from the SFE, liver glycogen concentrations were less than half that of the fed hatchery fish, consistent with the hypothesis of food limitation in the wild, but also several other potential causes. This study highlights the utility of liver glycogen as an indicator of recent foraging success in Delta Smelt.”

Featured Dataset Publications

  • Khanna, S. and J.W. Gaeta. 2023. Fluridone treatment data and SAV cover across the Sacramento - San Joaquin Delta (2014-2018) ver 1. Environmental Data Initiative.
    • In the Sacramento - San Joaquin Delta, California spends millions of dollars each year to treat submerged aquatic vegetation (SAV) such as Egeria densa and Myriophyllum spicatum. We integrated four different datasets to examine the efficacy of SAV treatment using fluridone over five years (2014-2018) across the entire ecosystem. For 132 sites across the Delta, we collated annual information on whether a site was treated, the amount of fluridone sprayed per site per unit area of SAV, consecutive years of treatment, and water speed within the site. This dataset was analyzed and the results of the analysis were published in a paper in Biological Invasions.
  • Stompe, D.K. and J.A. Hobbs. 2023. California Department of Fish and Wildlife Adult Sturgeon Study, Sacramento-San Joaquin Watershed, 1954-2022 ver 1. Environmental Data Initiative.
    • The Sacramento-San Joaquin Watershed, located in Central and Northern California, drains approximately 43,000 square miles and terminates at the Golden Gate Bridge. This watershed hosts numerous species of ecological, cultural, and recreational importance, including White (Acipenser transmontanus) and Green Sturgeon (Acipenser medirostris). Sturgeon were severely overfished in the late 1800s and early 1900s, prompting a closure of the recreational and commercial sturgeon fishery in 1917 by the California Department of Fish and Game (CDFG; Now California Department of Fish and Wildlife, CDFW). The fishery remained closed until 1954, when a recreational fishery was once again allowed by the CDFG. A single year of surveying was conducted by the CDFG in 1954 to monitor the new fishery and a semi-regular survey was established in 1967. Since then, CDFW has systematically surveyed subadult and adult White and Green Sturgeon as part of the Adult Sturgeon Study, with annual surveys conducted between 2005 and 2022. The adoption of PIT (Passive Integrated Transponder) tags began in 2007 and has been consistently employed since 2019. These data provide insights into tag return rates, recaptures, and mortalities, supporting the estimation of abundance and harvest rates. This comprehensive dataset enriches our understanding of sturgeon population dynamics and is crucial for monitoring California sturgeon.

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

  • December 4 Contaminants PWT Meeting 1:00 p.m. to 4:00 p.m.
  • December 7 Aquatic Vegetation PWT Meeting 1:00 p.m. to 3:00 p.m.
  • December 27 Zooplankton PWT Meeting 1:30 p.m. to 3:30 p.m.

Other Events or News

Frontiers for Young Minds: Where the river meets the ocean - Stories from San Francisco Estuary

IEP Blogs - Make sure to subscribe to receive the latest posts!

IEP Playlist on YouTube - collection of videos from IEP activities (e.g. Annual Workshop, Monitoring & Synthesis, DS Model Workshop)

IEP on X (formerly Twitter)