Shellfish Culture and Particulate Matter Production and Cycling P.A.G. Barnes Ecological Interactions Research Program Centre for Shellfish Research Malaspina University-College ticulate Deposition Rates, Sediment Geochemi nd Benthic Faunal Communities Associated wit eep-water, Suspended Pacific Oyster Farm in
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Shellfish Culture and Particulate Matter Production and Cycling P.A.G. Barnes Ecological Interactions Research Program Centre for Shellfish Research Malaspina.
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Shellfish Culture and Particulate Matter Production and Cycling
P.A.G. BarnesEcological Interactions Research Program
Centre for Shellfish ResearchMalaspina University-College
Particulate Deposition Rates, Sediment Geochemistry and Benthic Faunal Communities Associated with aDeep-water, Suspended Pacific Oyster Farm in BC
• Cultured bivalves filter feed on naturally occurring phytoplankton
• Fine suspended material is packaged into larger feces and pseudofeces (biodeposits)
• the size and nature of the farm - culture species, stocking density, overall production, biomass
• site characteristics - hydrography, bathymetry, primary productivity
• fouling communities on the raft structures
• mortality and fall-off of cultured bivalves and fouling organisms
Seasonal variation in some of these factors may be reflected in seasonal variation in biodeposition
Shellfish Culture and Particulate Matter Production and Cycling
BC Aquaculture Research & Development Committee (BCARDC)
Objectives:1. to quantify particulate matter (feces, pseudofeces) and sloughed material produced at deep-water, suspended Pacific oyster (Crassostrea gigas) raft culture sites in BC;
2. to quantify particulate material arriving on the seafloor per unit time (deposition rate) below the C. gigas rafts, adjacent to the farms, and at reference stations;
3. to measure water currents and water column variables which may affect biodeposit production rates and deposition rates at C. gigas study sites;
Shellfish Culture and Particulate Matter Production and Cycling
Objectives:
4. to investigate the effects of deposition from C. gigas farms on sediment physical and geochemical parameters;
5. to investigate the effects of deposition from C. gigas farms on benthic faunal communities during a period of
maximum productivity.
Village Bay, Quadra Island
Schematic – B. Kingzett
Field work • July 2003 to Aug. 2004• sampling every 3 months
Oyster density • 183 oysters ∙m-3
Variables studied, and samples collected/processed, in the field particulate study.
Category Variable Collection Method Sample Number
Water column Temperature1 Sonde profile 70
Temperature 2 TidBits (in situ) Continuous recording
Swartz Dominance Index (SDI) measures the number of species that comprise ~75% of the sample. A high SDI value indicates that abundance is spread relatively evenly over a variety of species. A low SDI indicates that a few taxa dominate the community.
Shellfish Culture and Particulate Matter Production and Cycling
Summary of Major Results – Village Bay
• Deposition rates• significantly higher at the raft station (S3) than reference stations on most dates
• Sediment geochemical characteristics • %TOM at S3 was significantly different (but not always higher) compared to %TOM at RS1 or RS2• redox values at S3 were not significantly different from those at RS1 or RS2 • free sulphides at S3 were significantly higher than those at RS1 or RS2 in July 2003
Shellfish Culture and Particulate Matter Production and Cycling
Summary of Major Results – Village Bay
• Sediment infaunal invertebrate communities• no indication of infaunal impoverishment at raft station• infaunal community at the raft station was distinct from those at other stations (hard substrate fauna, differences in dominant bivalves and polychaetes)
Acknowledgements:Funding:BC Aquaculture Research and Development Committee Advanced Systems Institute (BCIC)NSERC Canada Research ChairAssistance:Julia Rendall, Bee Islets Co-op Brian Stevenson, Viking Bay Ventures BCSGACSR – D. Tillapaugh, S. Switzer, W. Friesen,
A.Perkovich, S.Williams, K. Hunter, N. Plamondon, D.Dalziel, D. Paltzat
MU-C Department of Fisheries and Aquaculture - Gord Edmondson, Jenny Dawson-CoatesKingzett Professional ServicesBCMAFF - Dr. Bill HeathDFO - Institute of Ocean Sciences
Shellfish Culture and Particulate Matter Production and Cycling – Benthic Infauna
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Rochefortia tumida, Tectura persona &hard subtrate fauna