Fish Losses Due to Predation Workshop
One of the goals of the CALFED Science Program is to provide authoritative and unbiased descriptions of scientific knowledge. To fulfill this goal, the Science Program holds workshops designed to provide a forum for discussions and the exchange of information among Scientists, Stakeholders, Agency Staff, and the public about topics important to the region. These workshops synthesize the science related to complex problems and provide advice for undertaking specific complex tasks in support of Delta planning and decision-making.
The California Bay-Delta Authority (CBDA) hosted a 2-day workshop in June 2005 to examine technical issues associated with the losses of sensitive fish species to predators at the Sacramento-San Joaquin Delta intakes to the state and federal water projects. Estimating losses to predators (with the predators being mainly sub-adult striped bass) is part of a process used to calculate take (total number of fish lost to the system) of four races of juvenile Chinook salmon at the project intakes. These take levels are then used as part of the process to determine if project pumping should be reduced to protect the fish as well as to evaluate impacts of project pumping on these fish. The projects provide water to California's cities and farms, thus pumping reductions can affect reliability of this critical component of State's water supply.
Fish Losses Due to Predation at the State Water Project and Central Valley Project Delta Intakes - The final reports and supporting materials for the CALFED Technical Workshop held on June 22 and 23, 2005
The workshop goals were to:
- Examine the technical basis for present predation loss calculations.
- Determine if additional studies are needed to refine the loss estimating procedures and if they can be expanded to include other sensitive species such as steelhead and delta smelt.
- Assess the potential impacts and benefits of proposed physical and operational modifications at the project intakes and how these changes may affect losses to predators.
The CBDA and the California Department of Water Resources assembled a five person expert panel to assist the workshop attendees sort out the difficult technical questions associated with losses to predators. The panel was asked to provide an independent assessment related to the goals.
It was decided to provide a complete documentation for the workshop including a workshop summary by Wim Kimmerer and Randall Brown, the expert panel report, the PowerPoint slides from the workshop presentations and the technical reports from which much of the information related to predation in the SWP's Clifton Court Forebay has been drawn.
- Final Report - Fish Losses Due to Predation at the State Water Project and Central Valley Project Delta Intakes
The workshop PowerPoint presentations
- Intro: Importance of predation in Delta as related to water project operation.
- Questions for discussion.
- Initial Panel Response.
- Predators and predation at the intake to the Central Valley Project -preliminary study findings - Brent Bridges, USBR
- Proposed Changes in Delta Facilities and Suggestions to Reduce Predation Impacts - Ron Ott, CBDA Science Program
- Predation Studies and Management In the Columbia River Basin - Jim Petersen, USGS
- SWP and CVP Fish Protective Facilities - Darryl Hayes, P.E. CBDA
- The environmental context of predation losses in the South Delta - Wim Kimmerer, Romberg Tiburon Center, San Francisco State University
- Using Bioenergetics Models to Using Bioenergetics Models to Estimate Predation Rates Estimate - Kyle J. Hartman, West Virginia University
- Salvage at SWP and CVP intakes - Randall Brown, CALFED
- 2005 Pilot-Scale Investigation of Steelhead Predation within Clifton Court Forebay - Charles Hanson, Hanson Environmental Inc.
Supporting technical reports
- DRAFT: Food Habits of Striped Bass, White, and Channel Catfish in Clifton Court Forebay During 1983-84 and 1993-1995, George Edwards
- Predation Study Report, 1966-1967, James Orsi
- Mark/Recapture Experiments at Clifton Court Forebay to Estimate Pre-Screening Loss to Juvenile Fishes: 1976-1993, September 1997, Marty Gringas
- A Telemetry Study of Striped Bass Emmigration from Clifton Court Forebay: Implications for Predator Enumeration and Control, January 1997, Marty Gringas and Maureen McGee
- Hydroacoustic Monitoring of Fish Movement in Clifton Court Forebay Outlet Channel: June 1-4 1988, May 2002, Barry Collins, Robert Kano, Marty Gringas, and Robert Fujimura
- Movement Patterns of Striped Bass, Morone saxatilis in Clifton Court Forebay, Contra Costa County, California, Betsy C. Bolster.
- Ultrasonic Tracking of Striped Bass, Morone saxatilis, and Sacramento Squawfish, Ptychocheilus grandis, Near Fish Facilities, Frank A. Hall, Jr.
- Occurence and Abundance of Predator Fish in Clifton Court Forebay, California, Robert M. Kano
- Estimated Entrainment of Striped Bass Eggs and Larvae at State Water Project and Central Valley Project Facilities, in the Sacramento-San Joaquin Delat, 1987, Paul F. Raquel.
- The Clifton Court Forebay Sport Fishery, W. Lee, Mecum