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Published byJosie Bruley Modified over 9 years ago
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Overview A. Initial Introduction of Non-Native Species B. Coastwise Spread of Non-Native Species C. Verification of BWE
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Database LiteratureMonitoring Collections Records Reporting System Invasion Patterns Early Detection / Rapid Response Predictions Management Efficacy Management / Policy Outputs & Applications NEMESIS (National Exotic Marine and Estuarine Species Information System)
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Overview A. Initial Introduction of Non-Native Species B. Coastwise Spread of Non-Native Species C. Verification of BWE
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Non-native invertebrate taxa reported in coastal waters of North America (n=326)
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Assumptions for Current BW Management (BWE) BW is a Dominant Vector Invasion Risk is Greatest in Bays/Estuaries & Decreases Sharply with Distance offshore
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Ship Arrivals from Overseas Ballast Water Dischage: ~100 Million Metric Tons / YR Hull Surface Area: ~ 335 Million M 2 / YR
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Possible vector for coastal NIS introduced to North America by shipping (n=171)
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BW is a Dominant Vector
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Assumptions for Current BW Management (BWE) BW is a Dominant Vector Invasion Risk is Greatest in Bays/Estuaries & Decreases Sharply with Distance offshore
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Number of non-native invertebrate species reported for Pacific Coast bays 28% - 40%
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Macro scale organisms (zooplankton) Generally good agreement with assumption. Possibly source (habitat) dependent. There are exceptions to the “rules” (e.g. habitat sources and habitat generalists)
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Different for Microorganisms?
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Overview A. Initial Introduction of Non-Native Species B. Coastwise Spread of Non-Native Species C. Verification of BWE
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(r 2 =0.429; n=57) (r2=0.172; n=190)
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(n=57) (n=190) 17.5% 40.0%
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n=124 r 2 =0.168 San Francisco Bay invasions n=70
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Who Spreads from San Francisco Bay? Species with planktonic larvae: 23% Species with nonplanktonic larvae: 50%
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Summary: NIS spread (a)Spread patterns within coasts result from a combination of human-mediated transport and natural dispersal --- and their interactions with life history, behavior, abundance, habitat utilization, and current patterns. (b) Frequency differences in spread between coasts may result primarily from differences in “inter-island” distances and rates of natural dispersal.
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Assumptions for Current BW Management (BWE) BW is a Dominant Vector Invasion Risk is Greatest in Bays/Estuaries & Decreases Sharply with Distance offshore
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Relative Role of Ships’ Ballast vs. Hulls in Coastwise Spread?
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Overview A. Initial Introduction of Non-Native Species B. Coastwise Spread of Non-Native Species C. Verification of BWE
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Not exchanged (non-complying) exchanged (complying) The chemical signature of exchanged ballast water is more similar to water from the mid- ocean than water from its original coastal source.
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Distance from Shore Tracer Concentration Invasion Risk (prob of onshore transport)
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Effect of Ballast Water Exchange salinity: 36 33 30 27 salinity: 36 33 36 33 BWE greatly reduces concentrations of fluorescent components Exchanged CDOM > Ocean CDOM Signatures from all high salinity sources are similar salinity: 36 33 36 33
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