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Bottlenose Dolphins and Coastal Health Lori Schwacke, Ph.D. NOAA’s Cooperative Center for Marine Animal Health.

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Presentation on theme: "Bottlenose Dolphins and Coastal Health Lori Schwacke, Ph.D. NOAA’s Cooperative Center for Marine Animal Health."— Presentation transcript:

1 Bottlenose Dolphins and Coastal Health Lori Schwacke, Ph.D. NOAA’s Cooperative Center for Marine Animal Health

2 Stress on Coastal Ecosystems Loss of species Altered food webs ↑ algal blooms Disease/mortality of indicator species Ecological impacts ↑ fishery closures ↑ health risks ↓ recreational use ↓ aesthetic value Human impacts ↑ chemical contam. ↑ nutrient ↑ pathogens ↓ suitable habitat Changes to marine environment Increasing human population & coastal development Altered land, ↑ impervious surface ↑ pollutants, run-off Altered waterways ↑ fishing pressure Time

3 Bottlenose Dolphin (Tursiops truncatus)

4 U.S. Coastal Distribution

5 Why Study Dolphin Health? Dolphins are sentinels for coastal ecosystems: –Dolphin health reflects availability/quality of prey & habitat; reflects stressors in environment Chemical pollutants Biotoxins Pathogens –Increasing reports of dolphin disease and mortality raises concern about deteriorating ocean health Environmental stressors affecting dolphins can also affect humans

6 Chemical Contaminants Trace metals Pharmaceuticals Perflourinated chemicals (many consumer products) Persistent organic pollutants (POPs) –Chlorinated pesticides (DDT, chlordanes) –Polychorinated biphenyls (PCBs) –Brominated flame retardants Wash from land into estuaries via run-off from urban areas, industrial sites or agricultural fields Settle into sediments, enter into food chain when they are consumed by bottom-feeding (detrivore) organisms or absorbed by fish gills

7 Coastal Food Web 2° consumers (menhaden, juv. fishes such as red drum, croaker) zooplankton primary producers (phytoplankton) detrivores (shrimp, mullet) 3° consumers (trout) Organic debris, benthic microalgae

8 Biomagnification of Persistent Contaminants (e.g. PCBs) Plankton 0.04 ppm Small fish ppm Large fish 2-8 ppm Dolphins are top level predators, vulnerable to biomagnification Dolphins ~ ppm Organic debris

9 Bioaccumulation of PCBs Dolphins are long-lived and have lipid-rich blubber, so vulnerable to bioaccumulation Figure from Wells et al. 2005, Science of the Total Environment

10 Biotoxins Biotoxins are produced by certain species of phytoplankton Change in environment may cause dramatic increase in phytoplankton (bloom) Bloom of toxin-producing algae referred to as Harmful Algal Bloom (HAB) Cause fish-kills, intoxicate seafood

11 Brevetoxin Florida “red-tide” Neurotoxin shellfish poisoning, respiratory distress Source:

12 Panhandle Mortality Events 152 dolphins stranded, Aug.1999 – May dolphins stranded, Mar. – Apr. 2004, no observed bloom 93 dolphins stranded, Sep – Apr dolphins stranded, Aug.1999 – May dolphins stranded, Mar. – Apr. 2004, no observed bloom 93 dolphins stranded, Sep – Apr Cells Cells Cells Cells >10 6 Cells Dolphin stranding K. brevis cell count data

13 Brevetoxin Related Dolphin Mortality Events Texas Mississippi Louisiana Alabama Florida (152) 2004 (107) (93) (~200) Multi-species Gulf of Mexico

14 Why are dolphins in the Florida Panhandle dying? Unique exposure pathway/vector? Secondary stressor? *reported in Hall et al. 2007, Fair et al. 2006, Goldstein et al * * * Organic debris

15 Infectious Disease/Pathogens Viral disease –Morbillivirus –Encephalopathies (titers to equine encephalitis) Bacterial pathogens –Brucella, Leptospira Protozoal parasites –Giardia, Cryptosporidium, Toxoplasma Fungal disease –Lobomycosis, Aspergillosis Giardia Leptospira Brucella Zoonotic pathogen – infectious agent that can affect both dolphins and humans

16 Summary Dolphins are sentinels of coastal health Chemical contaminants –Top-level predator, vulnerable to biomagnification –Indicator of bioavailable contaminants –Reflect local trends in contaminant concentrations Biotoxins –Warn of biotoxins in the food chain, even when HAB is not detected; help to identify vectors for biotoxin exposure –Suggest potential for increased susceptibility, interactions with other stressors Disease/Pathogens –Warn of zoonotic pathogens in marine environment

17 Sampling Methods Remote Dart Biopsy Contaminants, genetics, fatty acid/stable isotope Capture-Release Physical exam, age, telemetry Health parameters – CBC, serology, immune suite, urinalysis, biotoxin exposure, etc. Stranding Response Cause of death, pathology Age, reproductive biology, diet Photo-ID Studies Distribution, population abundance, behavior Mortality/reproductive events Photo: Eric Zolman

18 The End

19 Acknowledgments NOAA Marine Mammal Health and Stranding Response Program (Panhandle dolphin health assessment project) NMFS Southeast Fisheries Science Center, Southeast Marine Mammal Stranding Network (Panhandle dolphin stranding data) Florida Fish and Wildlife Research Institute (K. brevis cell count data)

20 Microrray Picture? Blood samples are also used to look at gene expression and compare the patterns of expression between dolphins sampled under various environmental conditions. Scientists hope that such changes in gene expression can eventually be used to diagnose early signs of stress or disease and provide an early warning of emerging environmental problems. Microrray Picture? Blood samples are also used to look at gene expression and compare the patterns of expression between dolphins sampled under various environmental conditions. Scientists hope that such changes in gene expression can eventually be used to diagnose early signs of stress or disease and provide an early warning of emerging environmental problems. Microrray Picture? Blood samples are also used to look at gene expression and compare the patterns of expression between dolphins sampled under various environmental conditions. Scientists hope that such changes in gene expression can eventually be used to diagnose early signs of stress or disease and provide an early warning of emerging environmental problems. Microrray Picture? Blood samples are also used to look at gene expression and compare the patterns of expression between dolphins sampled under various environmental conditions. Scientists hope that such changes in gene expression can eventually be used to diagnose early signs of stress or disease and provide an early warning of emerging environmental problems. Microrray Picture? Dolphin Microarray Expressed Sequence Tags (ESTs) isolated from dolphin peripheral blood leukocytes Focused on stress response and immune function genes


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