White Catfish and Adult Striped Bass Diets in Suisun Marsh Teejay O’Rear (taorear@ucdavis.edu) and Peter Moyle (pbmoyle@ucdavis.edu) UC Davis Center for Watershed Sciences and Wildlife, Fish, and Conservation Biology Cal-Neva AFS 2015 • Santa Cruz, CA North Delta Arc working group: Matt Young, Denise DeCarion, Thomas Handley, Amber Manfree, Brian Williamson, Jacob Montgomery, Kathleen Berridge, Kousei Martin Perales, Felipe La Luz, Chris Jasper, Teejay O’Rear, Randy Dahlgren, William Fleenor, James Hobbs, John Durand, Peter Moyle
White Catfish and Adult Striped Bass Diets in Suisun Marsh 1. Key Suisun Marsh features 2. White catfish diets 3. Adult striped bass diets
Managed Wetlands Water Management Suisun Marsh wet wet dry Spr Win Sum Aut Oxygen:Variable Water Clarity: Low Year: 2009 a, b
Suisun Marsh – Why Do We Care? Waterfowl! Sacramento Splittail Otter Trawl Rank: #2 (28,348 fish) of 54 spp. Beach Seine Rank: #6 (3,821 fish) of 38 spp. a a, c, d
White Catfish Otter Trawl Rank: from #14 (1979-2001) to #5 (2002-2014) of 54 spp. a Adult Striped Bass a
White Catfish – Delta (Turner 1966) “They included Dorosoma petenense , Alosa sapidissima, Roccus saxatilis , Hypomesus olidus , Lampetra ayresi, e Clupea pallasi, and Lepomis macrochirus .” Striped Bass – Delta (Nobriga and Feyrer 2007) f
White Catfish Diets in Suisun Marsh? Unknown Questions: • What are white catfish eating? • Associated with habitat features? • Any habitat features explain piscivory of white catfish? Methods: • Stomach-pump (deck hose!) white catfish from Suisun Marsh Fish Study trawls • Sampling period: June 2009 – May 2010 • Correlate habitat variables to diet items (sal, temp, clarity, depth, DO, diversion density) Test habitat variables on piscivory •
White Catfish Diets in Suisun Marsh 56 54 71 48 • n = 304 fish • winter: 28 26 16 • spring: 135 • summer: 102 autumn: 39 • • 274 fish (90%) w/food • mean SL: 216 mm (adults); few<182 30 mm
White Catfish Diets in Suisun Marsh (no smelt/salmon) Very Tiny Things Very Tiny Things Daphnia magna CA bay shrimp Daphnia magna overbite clam Bio Photo Group, ON Eogammarus confervicolus shim. goby Bio Photo Group, ON Eogammarus stickleback confervicolus bay/slough wetland species species g
%Fish Mass in Diet of White Catfish: Correlates? Parameter Parameter Estimate t -ratio Probability > | t | Temperature 0.0063291 0.40 0.508 DO -0.078083 -2.54 0.014* Standard length 0.0013695 0.77 0.444 Temperature X DO 0.0053317 0.36 0.718 Temperature X standard Length 0.0003352 0.55 0.584 DO X standard length 0.0001548 0.22 0.829 Temperature X DO x standard length 0.0001271 0.38 0.706 Managed Wetlands Water Management circulate circulate water water DO = 2.9 mg/L dry g
Adult Striped Bass • Sample period: October ‘09 81 – ongoing (opportunistic!) • hook-and-line 20 • stomach pumped 25 17 • n = 373 fish • winter: 122 • spring: 139 54 • summer: 24 35 • autumn: 88 39 • 315 fish (84%) w/food • mean TL: 55 cm (22 in); range: 45 – 91 cm • 5 feeding areas: 79 • seams (13 fish) • drains (228) • pumps (52) • rock (18) • tidal creeks (40) • PRELIMINARY!
Adult Striped Bass Diets: Fish Prey Numbers (?) (no smelt/salmon) 2009 - 2014 Method Silversides Shads Sticklebacks Sculpins Fish/ Trawl 0.09 0.53 0.64 0.72 Fish/ Seine 33.95 1.12 2.03 0.25 Fish/ Pumped Striped Bass 0.08 0.04 15.9 0.84
Adult Striped Bass Diets: Feeding Area
Adult Striped Bass Diets: Frequency of Occurrence
Conclusions • Adult striped bass: fish diet dominated by slow-moving benthic/littoral fishes…turbidity? • Both species: no salmon/smelt eaten/identified • Both species: most food from wetlands…trophic relay?
Thanks! Mike Wigginton, Phil Antipa, everyone at the Suisun Marsh Branch of DWR, the Suisun Resource Conservation District, Melissa Riley (CDFW), the entire North Delta Arc Working Group (especially Brian Williamson), Alison Furler (CDFW), Tommy Agosta (UCD), Rachel Johnson (NMFS), Fred Feyrer (USGS), Alpa Wintzer , Rob Schroeter, Jason Moore (DWR), Patrick Fuller, Amy Chandos, Nick Buckmaster (CDFW), Miranda Bell (UCD), Nicky Bunn, Angie Munguia (DWR – formerly!), Eva Bush (UCD), Nick Corline (“Mudbug”; UCD), Carson Jeffres (UCD), Emma Davidson (UCD), Josh Porter (EB Parks), Lily Tomkovic (UCD), Scott McDonald (CSUSJ), Hailey Pexton (UCD), Paul Takemoto (UCD), Robert Dunn (UCD), Joe Rogers, Georgia Ramos (UCD), Karin Petrites (Putah Creek Council), Emma Cox, Thaddeus Hunt, Quoc Van, Ethan and Janet Kean... Funding provided by California Department of Water Resources and private donors
References a. O’Rear, unpublished data b. Siegel, S., P. Bachand, D. Gillenwater, S. Chappel, B. Wickland, O. Rocha, M. Stephenson, W. Heim, C. Enright, P. Moyle, P. Crain, B. Downing, and B. Bergamaschi. 2011. Final evaluation memorandum, strategies for reducing low dissolved oxygen and methylmercury events in northern Suisun Marsh. Prepared for the State Water Resources Control Board, Sacramento, California. SWRCB Project Number 06-283-552-0. c. California Department of Fish and Game. 1996, 1997, 1998. Fishery monitoring program a component of the Suisun Marsh Diversion Screening Program. University of California, Davis, California. d. Pickard, A. A. Baracco, and R. Kano. 1982. Occurrence, abundance, and size of fish at the Roaring River Slough intake, Suisun Marsh, California during the 1980-81 and the 1981-82 diversion seasons. Technical Report 3, California, California Department of Fish and Game. e. Turner, J. L. 1966. Distribution and food habits of ictalurid fishes in the Sacramento-San Joaquin Delta. Pages 130-143 in J. L. Turner and D. W. Kelley, editors. Ecological Studies of the Sacramento-San Joaquin Delta, part 2. California Department of Fish and Game Fish Bulletin 136. f. Nobriga, M. L., and F. V. Feyrer. 2008. Diet composition in San Francisco Estuary striped bass: does trophic adaptability have its limits? Environmental Biology of Fishes 83: 495-503. g. O'Rear, T. A. 2012. Diet of an introduced estuarine population of white catfish in California. Master's thesis. University of California, Davis.
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