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Heather wolfer , phd student, umes

Sublethal Effects of Hypoxia on Atlantic croaker ( Micropogonias undulatus ) in the Chesapeake Bay. Heather wolfer , phd student, umes. Low dissolved oxygen (DO) in water column Both natural and anthropogenic causes Increasing global problem. Hypoxia.

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Heather wolfer , phd student, umes

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  1. Sublethal Effects of Hypoxia on Atlantic croaker (Micropogoniasundulatus) in the Chesapeake Bay Heather wolfer, phd student, umes

  2. Low dissolved oxygen (DO) in water column Both natural and anthropogenic causes Increasing global problem Hypoxia

  3. Hypoxia, Chesapeake Bay, & croaker Kemp et al. 2005 • Largest US estuary • Long history of hypoxia • Large human impact • Croaker commercially important • Found in hypoxic areas Wicks et al. 2007

  4. Chesapeake used for industrial, commercial, and recreational purposes Hypoxia can negatively affect water quality and aquatic organisms (ex. croaker) Project importance Croaker !

  5. Acoustic Telemetry Study: Summer 2011 Lab Hypoxia Study: Summer 2011 & 2012 Field Hypoxia Study: Summer 2012-13 Project Layout

  6. Telemetry: Determine behavioral responses between normoxic and hypoxic sites • Lab/Field: Determine physiological effects under hypoxia • Quantify immune, general health, and reproductive effects objectives

  7. Acoustic telemetry • Spring and Summer 2011 • Stratified and reference sites • 56 fish total • Day and day/night sessions • Vemco VR-100 Receiver • Directional & 360º hydrophones

  8. Tagging • V91P-L transmitter (depth sensor) • Benzocaine anesthetic • Surgical implantation • External T-bar tag • Recovery • Release

  9. Dissolved oxygen Tangier Sound (Reference) Point No Point (Stratified)

  10. Croaker utilize deep channels Some indication of shallow water use in hypoxic site Prefer benthic structures (holes, oyster sanctuaries, lighthouses) Less overall movement in later session Greater mobility at night Tracking data

  11. STRATIFIED REFERENCE

  12. Determine physiological effects under hypoxia • Quantify immune, endocrine, and reproductive effects • Phagocytosis – immune function response • Organosomatic Indices –overall health, immune & reproductive response • Hematology – general health; stress; homeostatic & osmotic balance • Lab trials will determine indicators for use in field study Lab/Field Objectives

  13. Lab trial 1 – Summer 2011 • 24, 48, and 72h trials • 1.5 mg/L DO • Hematology • Plasma chemistry • Electrolytes • Complete Blood Count • Differential leukocyte count • Organosomatic Indices • Hepatosomatic (HSI) • Splenosomatic (SSI) • Gonadosomatic (GSI)

  14. Results & discussion • Decreased HSI & SSI in hypoxic fish (48 & 72h) • Indication of stress • Recruitment of blood into circulation • Neutrophilia and lymphocytopenia in 24h hypoxic fish • Innate immune response • Increased glucose *

  15. Summer 2012 FIELD SAMPLING LAB TRIALS

  16. WORKSHOP: HEMATOLOGY Blood Drawn Blood put in centrifuge Anesthetized fish are bled Blood smears Hematocrit Electrolytes Extract plasma Plasma protein Plasma chemistry

  17. Workshop: health assessment FIRST DORSAL SECOND DORSAL LATERAL LINE EYE CAUDAL FIN GILLS ANAL FIN PECTORAL FIN PELVIC FIN

  18. Internal assessment & indices Brain & Otoliths Swim Bladder • Hepatosomatic (HSI) • Environmental stress • Nutritional status • Splenosomatic (SSI) • Immune response • Blood capacity and transfer • Gonadalsomatic (GSI) • Gonadal growth • Reproductive response Kidney Liver Gonads Spleen

  19. Studies of Chesapeake Bay and At. Croaker important to understanding human impact on environment Hypoxia is a growing problem that causes serious behavioral and physiological effects If we don’t understand more about hypoxia and its effects, this is the result: Conclusion FISH KILL

  20. Acknowledgements Capt. Daniels & El Diablo Eshaddai Ephrem SEEL Luis López-Cruz Ria Mandan Nivette Perez-Perez

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