Limiting Factors in the Success of Habitat Restoration Sites for O. Conchaphila in San Francisco Bay

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Limiting Factors in the Success of Habitat
Restoration Sites for O. Conchaphila in San
Francisco Bay

• For the
• 9th International Conference on Shellfish
  Restoration
• Charleston, SC
• November 17, 2006

By Robert R. Abbott, Rena Obernolte MACTEC
Engineering and Consulting Inc. Brian
Mulvey Kleinfelder, Inc.
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Pilot Project Objectives

• Demonstrate the feasibility of reestablishing
  self-sustaining populations
• Obtain data to help identify limiting factors
• Substrate - Predation
• Water quality - Disease
• Other (circulation, population densities, larval
  sinks,?)
• Identify appropriate conditions and methods for
  reestablishment
• Establish connection with tidal marsh?
• Develop better understanding of genetics

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• 3 Project Locations
• Marin Rod and Gun Club
• Bair Island
• Sailing Lake

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BAIR ISLAND SITE

• Near Redwood City
• In
• South San Francisco Bay

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BAIR ISLAND FEATURES

• Tidelands adjacent to tidal marsh preserve
• Implications for South Bay Salt Ponds ?
• -1 feet to -3 feet re MLLW
• Oyster drill 1/m2 (Harris 2004)
• South SF Bay water regime
• Long retention time
• Euryhaline conditions
• Historical native and commercial oyster
  utilization

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OYSTER DRILLS

• Only observed in South Bay to date
• High densities at project sites near Bair Island
• Many mortalities observed (younger oysters)
• Overall not much of a limiting factor
• Other sources of mortalities outweigh drills

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2006 Pallet Installation
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BAIR ISLAND RESULTS

• Overall survival at the end of one year higher
  than other sites (a very wet year)
• Oyster drills have not been observed to be as
  limiting as other factors
• Used extensively by gobies, and opportunistic
  organisms
• Much increased set using hanging bags in 2nd year
  
• Different environment
• Local oyster population now present
• Predator access possibly reduced
• 2006 pallet shell recruited much better than 2005
  pallet shell

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BAIR ISLAND PROJECT ACKNOWLEDGEMENTS

• NOAA Corps, NOAA Fisheries Santa Rosa, and NOAA
  Restoration Center
• Marine Science Institute
• USGS
• California Department of Fish and Game
• Volunteers from Save the Bay, SERC, MRGC, local
  residents
• Funding provided by
• US Fish and Wildlife Service
• Coastal America
• San Francisco Bay Joint Venture

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MARIN ROD AND GUN CLUB

• SAN RAFAEL
• In
• North San Francisco Bay

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Marin Rod and Gun Club Site

• 40 Acres owned fee simple
• Club members committed to conservation
• Voted on a three year program
• Phase 1-Strings
• Phase 2-strings, stakes, pallets
• Phase 3-Reef rows
• Eelgrass
• Recreational anglers
• Fish utilization study
• Water quality effect on survival

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Project Location Map
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Recreational Angler CPUE 2006
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POTENTIAL LIMITING FACTORS

• Substrate
• Sedimentation
• Salinity (depth)
• Mortality
• Spawning
• Competition
• Varies seasonally and annually

• Predation
• Disease ?
• Dissolved oxygen?
• Permits
• Considered fill
• Large projects difficult to permit
• (gt 0.25 acre)

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FUTURE RESEARCH

• Continue studies of recruitment, growth and
  survival through time
• Establish monitoring program for predators and
  disease (green crabs, oyster drills, etc.)
• Increase monitoring to include fish and
  invertebrate utilization of oyster shells and
  reef structures
• Continue trying different substrates,
  configurations, and variations in time and depth
  of placement

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ACKNOWLEDGEMENTS

• Todd Meyer Club, Jerry McEowen, Mike Guenza, Paul
  Tarzia and Bill Craig and the whole Marin Rod and
  Gun Club team
• Natalie-Cosentino Manning, Eric Bohaboy and
  everyone at the NOAA Restoration Center and NOAA
  Fisheries Santa Rosa
• Over 100 Volunteers from the Marin Conservation
  Corps and California Conservation Corps, and 4
  Bay Area Universities, house wives, Save the Bay,
  etc.
• Students from 4 Bay Area high schools
• San Francisco Bay Joint Venture
• Kevin Lunny Drakes Bay Oyster Farm

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SAILING LAKE

• Shoreline Park in Mountain View
• South San Francisco Bay

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Sailing Lake

• 47 acres saltwater recreational lake
• Impermeable clay bottom
• Built in 1982
• Up to 16 deep
• Bottom DO 0 ppm at times
• No predators

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SAILING LAKE OYSTER BED
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Sailing Lake links with San Francisco Bay via
pumps from inner Charleston Slough
San Francisco Bay
Sailing Lake
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Sailing Lake Results

• Bags of cultch placed on the bottom (4m) for 7
  weeks collected approximately 4 spat per cultch
  shell
• The deepest bags collected the most spat
• Oysters were evaluated by CDFG before being moved
• Sailing Lake oysters appear to have better
  survival than natural sets at Bair Island and
  Marine Rod and gun Club