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Inferences for Biological Transport: Results from a West Coast Drift Card Study

Inferences for Biological Transport: Results from a West Coast Drift Card Study. Vanessa M. Howard & Mark Sytsma Portland State University. Alternative Ballast Water Exchange Areas Workshop June 21, 2006 – Seattle, Washington. Outline. Background Methods Results

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Inferences for Biological Transport: Results from a West Coast Drift Card Study

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  1. Inferences for Biological Transport:Results from a West Coast DriftCard Study Vanessa M. Howard & Mark Sytsma Portland State University Alternative Ballast Water Exchange Areas Workshop June 21, 2006 – Seattle, Washington

  2. Outline Background Methods Results Return rates & recovery time Recovery patterns - spatial & seasonal Summary

  3. Schwartzlose 1963 Background www.noaanews.noaa.gov Circulation patterns/currents (Schwartzlose 1963, Heath 1969, Dewees & Strange 1984) Situation of marine protected areas (Klinger & Ebbesmeyer 2001) Sewage outfall(Crone et al 1998, Sauers et al 2001) Floating materials hypothetical oil spill (NOAA’s 2005 Safe Sancuary Drill in FL Keys NMS) floating pollutants (NOAA’s 2002-04 Hawaii Drift Card Study)

  4. Photo courtesy of NRCS Objectives • Understand potential seasonal &/or spatial patterns of ocean dispersal from three heavily infested bays • Understand relative risk posed by various Spartina species • Identify common debris collection zones • Education & outreach

  5. Methods – Card Design • Buoyant plywood cards (10 cm x 15 cm) • Biodegradable - designed to persist 3-6 months • Coded for release date and location • NOAA specifications (Oahu, Hawaii Drift Card Study 2002-2004)

  6. Willapa Bay Humboldt Bay San Francisco Methods – Releases • Three release locations • September 2005 through August 2005 • 200 cards • Within two hours of high tide

  7. Results – return rates Willapa 41.8%

  8. Results – return rates Humboldt 26.2%

  9. Results – return rates San Francisco 43.8%

  10. Recovery time

  11. Results – bay vs. coast

  12. Results – near vs. long distance

  13. WB releases • Max North ~ 2,000 km (129 days) • Max South ~ 300 km (227 days)

  14. WB releasesSeasonal Patterns

  15. Willapa: Estimated velocitiesmean (range)

  16. HB releases • Max North ~ 2,800 km (214 days) • Max South ~ 530 km (45 days)

  17. HB releases Seasonal Patterns

  18. Humboldt: Estimated velocitiesmean (range)

  19. SF releases • Max North ~ 630 km (56 days) • Max South ~ 400 km (151 days)

  20. Known S. alterniflora x foliosa hybrid SF releases Seasonal Patterns

  21. San Francisco: Estimated velocitiesmean (range)

  22. Discussion Limitations: • Simulates surface transport only • Does not account for life history or behavior • May underestimate velocities • Does not account for inter-annual variation Applications: • Knowledge of near-shore, coast-wise transport • Emphasizes seasonal nature of dispersal • Identifies likely collection zones • Inexpensive - allowing greater numbers of replicates

  23. Summary • Drift from these three locations has a large seasonal component, generally following known patterns of ocean currents • Highest northward velocities & transport seen in WB & HB winter releases • Lower velocities & transport from SF • Local deposition more likely than distant, although rapid long-distance transport seen in certain instances • Question of transport into estuaries? • Additional releases of drift cards may help identify collection zones

  24. Acknowledgements Funding San Francisco Estuary Institute Oregon Department of Agriculture Washington Department of Fish & Wildlife Collaborators Kristen Ward, Golden Gate National Recreation Area (NPS) Travis Haring, Russell Nunez, Les Holcomb and David Heimer, WDFW Bill Pinnix, USDFW - Arcata office Volunteers Beachwatch (CA) COOAST (WA & OR) SOLV (OR) Beachcombers, tourists, children & many others

  25. Questions ?

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