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Oyster ( Crassotrea virginica ) monitoring in the St. Lucie Estuary

Oyster ( Crassotrea virginica ) monitoring in the St. Lucie Estuary. Melanie Parker and Steve Geiger Associate Research Scientist Fish and Wildlife Research Institute 100 Eighth Avenue SE St. Petersburg, FL 33701 Melanie.Parker@myFWC.com. Outline. Background information

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Oyster ( Crassotrea virginica ) monitoring in the St. Lucie Estuary

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  1. Oyster (Crassotrea virginica) monitoring in the St. Lucie Estuary Melanie Parker and Steve Geiger Associate Research Scientist Fish and Wildlife Research Institute 100 Eighth Avenue SE St. Petersburg, FL 33701 Melanie.Parker@myFWC.com

  2. Outline • Background information • Water Flow in SE Florida • CERP • Oyster Monitoring • Methods • Preliminary results and trends • Summary

  3. Water Flow in South Florida • Historically, drainage patterns were characterized by slow, surface flows through rivers, creeks, sloughs and marshes • Natural system absorbed floodwater, promoted ground water recharge, assimilated nutrients and removed suspended materials • As south Florida developed, the resulting canal network drastically altered the quality, quantity, timing and distribution of freshwater entering the estuaries SFWMD

  4. Water Flow in South Florida Historic Flow Current Flow Restored Flow U.S. Army Corps of Engineers, Jacksonville District

  5. Comprehensive Everglades Restoration Plan (CERP) • Implemented as means of reinitiating natural freshwater flow to both coasts of south FL • Realized through habitat enhancement and water storage/treatment projects • Monitoring component of CERP addresses impacts of changed freshwater flow on flora / fauna • Eastern oyster chosen as a target species for CERP

  6. Water Flow Impacts • Current water management practices involve releases of large volumes of freshwater over short periods of time • Flood releases and urban runoff contain many contaminants from urban and agricultural development • Sudden drops in salinity lead to decreased growth, reproduction, recruitment and even death of oysters in the estuary • Drastic changes in salinity can increase oyster disease prevalence and intensity • Freshwater inflows are often too great in the wet season and too little in the dry season

  7. CERP Objectives • Reduce the impacts of freshwater releases • Restore more natural freshwater inflows into estuaries • More optimal salinities • Reduction in nutrient loads • Improved water clarity • RESULT - promote reestablishment of healthy oyster reefs • Added benefit to other organisms that use oyster reef habitat

  8. Oysters as an Indicator Species • Dominant species in Florida estuaries • Salinity and other water quality conditions that are suitable for oysters are also ideal for many other organisms • Keystone species – habitat, filtration, shoreline and sediment stabilization • Sedentary nature of oysters allows for generation of cause-and-effect relationships between environmental conditions and oyster health

  9. CERP-Funded Oyster Monitoring in the St. Lucie Estuary

  10. St. Lucie Estuary Study Sites • North Fork • South Fork • Middle Estuary • 3 monitoring stations in each site

  11. Oyster Monitoring Components • Abundance and Distribution • Juvenile Recruitment • Reproductive Development • Perkinsus marinus • Disease Prevalence • Disease Intensity • Water Quality

  12. Results • CERP is a long term project • Potential 50 years of oyster monitoring • We are in Year 6 – began in 2005 • Results are preliminary • No major changes in water management practices • General trends / Storm events

  13. Salinity 7-9 mos below 5ppt 2-3 mos below 5ppt 2-5 mos below 5ppt

  14. Rainfall • 2005 – Wettest Year of study • Most active storm season to date • Hurricane Wilma in October • 2006 – Driest Year of study • 2007 – Tropical Storm Barry in June • 2008 – Tropical Storm Fay in August

  15. Canal Control Structures Rainfall • Canal 23 – S97 Water Releases • Canal 24 – S49 • Canal 23 – S48 • Canal 44 – S80

  16. Water Releases - Flow

  17. Density Highest Live Densities: 2007, Spring 2008, and 2010 99% Dead

  18. Shell Height Largest Shell Heights: Spring 2005 and Spring 2008

  19. Recruitment

  20. Reproductive Development

  21. Dermo Disease Prevalence

  22. Dermo Disease Intensity

  23. Summary • St. Lucie estuary strongly impacted by water management practices • 2005 and 2008 die off • Timing and extent of freshwater releases impacts recovery time of oysters in St. Lucie • 2005 – 6 months of high FW flow, recovery in Fall 2006 • 2008 – 2 months of high FW flow, spat set in November • Die-offs can also destroy recruitment substrate as shells become unconsolidated and buried by sediment • 2010 – No oyster die-off but low recruitment rates • Poor egg quality? • Poor larval survival and settlement?

  24. Next Steps… • What can we do to better summarize the biological data for water management? • Can we determine the relationship between flow releases and salinity patterns in the estuary? • How do releases from the three canals impact each site? • Can we determine ideal water release levels (cfs) to maintain suitable conditions in the estuary? • Maximum rate / duration? • Promote adult and larval survival • Data Exploration • Can we quantify differences between sites/years with salinity? • Biological Parameter vs. Salinity regressions

  25. Acknowledgements FWC Molluscan Fisheries crew Sarah Stephenson, Janessa Cobb, Anthony Vasilas, Michael Drexler, Lindsey O’Hearn, Bethany Pierce Former Molluscan Fisheries crew members Bill Arnold, Brett Pittinger, Carla Beals, Brandy Brown, Jennifer Davenport, Sara Bergeron Histology Lab Center for Biostatistics and Modeling Yvonne Waters, Noretta Perry Erin Leone South Florida Water Management District Patti Gorman, Patty Goodman, Darlene Marley FGCU– Aswani Volety HBOI – John Scarpa

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