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The Problem – Pre-Screen Loss at Clifton Court Forebay The Plan – A Multi-pronged Approach Bioenergetics Modeling : Models to be determined based upon.

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Presentation on theme: "The Problem – Pre-Screen Loss at Clifton Court Forebay The Plan – A Multi-pronged Approach Bioenergetics Modeling : Models to be determined based upon."— Presentation transcript:

1 The Problem – Pre-Screen Loss at Clifton Court Forebay The Plan – A Multi-pronged Approach Bioenergetics Modeling : Models to be determined based upon species and system specific constraints Predator Composition and Diet Studies (Fish): Field sampling will include gill netting and hook and line. Will provide fish for use in biotelemetry, mark/recapture, and genetic analysis studies. Will provide information on the seasonal demographics of the fish. Sampling will be conducted year round, with a goal of capturing up to 250 fish large enough to acoustically tag per year, and up to 250 fish too small to acoustically tag, which can be fitted with PIT tags. The minimum number of fish needed for the full gut (fish to be sacrificed) genetic analysis will be determined. Predator Composition and Diet Studies (Genetics): Collect full preserved guts from fish, and pellets or feces from birds. Analyze to determine species composition of prey base. Need adequate number of samples from above (to be determined). Assays being developed by other studies. Pilot study beginning in water year 2013/2014. Pilot study will be used to design a future full scale study. Behavioral Studies (Biotelemetry): A full scale biotelemetry study will be undertaken, using methods based upon prior similar studies. Stationary receivers will be placed in the Forebay, West Canal, and Old River. Environmental data will be taken simultaneously via dataloggers. Behavioral Studies (Hydroacoustics): Pilot study the first year Survival Studies: Salmonids and predatory fishes will be tagged for mark/recapture studies. PIT tagging of salmonids will be done in a lab setting. PIT tagging of predators will be done in the field. All predators will be double tagged, PIT + Floy, or Acoustic + PIT. Predator Composition and Diet Studies (Avian): Observational studies (point counts and descriptive information regarding bird behavior). Camera based observation (using a camera trap). Attempts to locate roosting areas, areas of frequent defecation or pellet expulsion, etc. Pilot studies will be used to assess the feasibility of expanded studies and to design the full scale studies. Predator Composition and Diet Studies (Creel): Fishermen will be interviewed to gather information on Catch Per Unit Effort (CPUE) and demographics of catch. Because the local fishing community at Clifton Court Forebay is racially and culturally diverse, an effort will be made to translate a simple card explaining the surveys into the most commonly used languages at the Forebay. Anticipated currently: Spanish, Vietnamese, Laotian, and Hmong. To encourage the return of tags an incentivized program will be explored. Veronica Wunderlich Bay-Delta Office, Delta Conveyance, Fish Science Investigations of Predator-Prey Dynamics in the Clifton Court Forebay to Guide Approaches to Reducing Pre-Screen Losses Clifton Court Forebay is the regulating reservoir whereby water is diverted from Old River into the State Water Project (SWP) Harvey O. Banks Pumping Plant, and ultimately into the California Aqueduct. NMFS has required that DWR implement the reasonable and prudent alternative (RPA) action (IV 4.2(2)) of the Biological Opinion and Conference Opinion on the Long-term Operations of the Central Valley Project and State Water Project (NMFS 2009) to reduce predation of ESA protected salmon and steelhead within the Forebay. Fish Entrainment at Clifton Court Forebay Fish enter the Forebay via the radial gates Fish must cross 2.1 mile width of Forebay to Skinner Fish Protective Facility (SFPF) where they can be salvaged and released. Pre-Screen Loss (PSL; loss of fishes within the Forebay prior to salvage) High rate of PSL for Chinook salmon and steelhead. Predation is considered synonymous with PSL. Reduction in predation is needed. Predator-Prey dynamics are poorly understood in the Forebay. Striped Bass are considered primary predator of salmonids. Understanding Predator/Prey Interactions: Striped bass abundance, residence time, seasonal demographics, and predation habits. Abundance, residence time, seasonal demographics, and predation habits of non-striped bass fish and bird predators. Salmonid Survival: Salmonid pre-screen survival Catch Per Unit Effort Skinner Fish Protective Facility Radial Gates The Results - Reporting Annual update reports with findings (if available) and recommendations. Final Synthesis Report at the end of the final year of the study, summarizing the findings. The Objectives – Finding the Culprits The Team – Collaborators Principle Investigator – Veronica Wunderlich Project Manager – Kevin Clark Support Staff: DWR - Bay-Delta Office, AECOM, Hansen Environmental, West Inc., HTI, and Cramer Fish Sciences.


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