The FMWT was initiated to determine the relative abundance and distribution of age-0 striped bass (Morone saxatilis), delta smelt (Hypomesus transpacificus), longfin smelt (Spirinchus thaleichthys), American shad (Alosa sapidissima), splittail (Pogonichthys macrolepidotus), and threadfin shad (Dorosoma petenense) in the estuary. FMWT has sampled annually since it's inception in 1967, with the exceptions of 1974 and 1979, when sampling was not conducted. 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.
The FMWT conducts compliance monitoring in collaboration with USBR and DWR to meet permit obligations to the SWRCB (and DRCB) via Water Rights Decisions (D-1485 and D-1641) and USFWS-NMFS biological opinions for Delta Smelt (Hypomesus transpacificus) and salmonids, and for incidental take permits issued by CDFW for operation of the State Water Project (SWP), and the USBR BA/ROD. FMWT also informs Natural Resource Agency Delta Smelt Resiliency Strategy management actions including the Suisun Marsh Salinity Control Gate re-operation and the North Delta Food Web Managed Flow actions. FMWT is used to inform Effects of Outflow Alteration upon Delta Smelt Habitat, Condition, and Survival and Summer-Fall Habitat Action monitoring.
Project Objectives • To annually measure the abundance and distribution of selected species of pelagic fishes in the estuary. • To gain understanding of the factors affecting abundance, distribution, and survival of pelagic fishes in the estuary. • To detect introductions of new exotic fish and invertebrates. • Provide baseline data to evaluate management plans and habitat restoration projects. • To measure availability of fall planktonic food resources.
The Summer Townet Survey (STN) is a long-term effort to monitor young pelagic fishes in the upper San Francisco Estuary. Since 1959, STN has sampled locations from eastern San Pablo Bay to Rio Vista on the Sacramento River, and to Stockton on the San Joaquin River; and a single station in the lower Napa River. The study area was expanded in 2011 to include the Sacramento Deep Water Ship Chanel and Cache Slough. Currently, 40 stations are sampled as a survey every other week June through August for a total of 6 surveys. Fish sampling uses a conical, fixed-frame net, which is pulled obliquely through the water column 2 to 3 times at each station. Data collected at 31 stations are used to calculate annual relative abundance indices for age-0 Striped Bass (Morone saxatilis) and Delta Smelt (Hypomesus transpacificus). The remaining 8 stations are sampled to increase our understanding of juvenile fish abundance and distribution in the lower Napa River and the north Delta. Starting in 2005, a zooplankton net was added to assess fish food resources at each station and a subset of the fish collected are retained for diet analysis by CDFW researchers. Zooplankton sampling informs several management actions focused on Delta Smelt habitat improvements including collections of additional zooplankton samples for the Suisun Marsh Salinity Control Gate re-operation. Finally, the STN also measures environmental variables including water temperature, water clarity and specific conductivity. Managers and researchers use data collected by STN to inform decisions and improve and understand the health of the upper San Francisco Estuary.
Tradeoffs among objectives in natural resource management can be exacerbated in altered ecosystems and when there is uncertainty in predicted management outcomes. Multicriteria decision analysis (MCDA) and value of information (VOI) are underutilized decision tools that can assist fisheries managers in handling tradeoffs and evaluating the importance of uncertainty. We demonstrate the use of these tools using a case study in the Sacramento River, California, U.S.A., where two imperiled species with different temperature requirements, winter-run Chinook Salmon (Oncorhynchus tshawytscha) and Green Sturgeon (Acipenser medirostris), spawn and rear in the artificially cold Shasta Dam tailwater. A temperature-control device installed on Shasta Dam maintains cool water for Chinook Salmon; however, uncertainties exist related to the effects of temperatures on the spawning and rearing of both species. We consider four alternative hypotheses in models of early life-stage dynamics to evaluate the effects of alternative temperature-management strategies on Chinook Salmon and Green Sturgeon management objectives. We used VOI to quantify the increase in management performance that can be expected by resolving hypothesis-based uncertainties as a function of the weight assigned to species-specific objectives. We found the decision was hindered by uncertainty; the best performing alternative depends on which hypothesis is true, with warmer or cooler alternative management strategies recommended when weights favor Green Sturgeon or Chinook Salmon objectives, respectively. The value of reducing uncertainty was highest when Green Sturgeon was slightly favored, highlighting the interaction between scientific uncertainty and decision makers' values. Our demonstration features MCDA and VOI as transparent, deliberative tools that can assist fisheries managers in confronting value conflicts, prioritizing resolution of uncertainty, and optimally managing aquatic ecosystems.
The Sacramento River and its tributaries serve as critical habitat for the green sturgeon, listed as federally threatened due to its declining population and the impacts of anthropogenic activities such as dam operations and water extraction. We currently lack an understanding of the relationship between flow regimes and sturgeon migration, which is essential for developing effective management strategies to support the species' conservation and for required analysis under state and federal law. By modeling this relationship, this project will contribute to more informed water management, leading to fewer litigation risks for agencies and better outcomes for sturgeon.
This project will model the effects of flow regimes on adult Southern Distinct Population Segment (sDPS) green sturgeon migration within the Sacramento River basin to enhance sturgeon conservation and water management. Specifically, the research will model how flows and temperature affect adult green sturgeon spawning migration. The model will be used to forecast sturgeon movements under various flow scenarios, and the model, the results, and an explanation of their significance will be widely distributed via a website (with a publicly accessible modeling app), a policy brief, a public workshop, and other outreach.
SacPAS serves to provide information integration services to the Central Valley Project Improvement Act and practitioners working on matters related to ESA-listed fishes. The web-based services relate fish passage to environmental conditions and provide resources for evaluating the effects of river management and environmental conditions on salmon passage and survival.
The work performed as part of this agreement includes developing, maintaining, and making accessible query tools and decision support tools to access: historical, real-time and forecasted data; data summaries and visualizations; and hindcasts, forecasts, and scenario-derived predictions from statistical and mechanistic models. More specifically, the objectives are to:
1) Maintain and extend a secondary data repository of historical, real-time, and forecasted fish, environmental, and operational data from the Sacramento River and other river systems in the Central Valley, integrated from primary, public databases.
2) Maintain and improve the data query and visualization tools and services provided through the SacPAS website (https://www.cbr.washington.edu/sacramento/) for historical, real-time, and forecasted environmental and fish data.
3) Conduct research and provide access to modeling tools for fish survival and migration, through the SacPAS website, in support of Reclamation-funded and ESA-mandated activities, especially in efforts to predict, track, and evaluate the efficacy of proposed or actual actions.
