Bottlenose Bottlenose Dolphins and Dolphins and Coastal Health Coastal Health Lori Schwacke, Ph.D. Lori Schwacke, Ph.D. NOAA’s Cooperative Center for Marine Animal NOAA’s Cooperative Center for Marine Animal Health Health
Dec 15, 2015
Bottlenose Dolphins Bottlenose Dolphins and Coastal Healthand Coastal Health
Lori Schwacke, Ph.D.Lori Schwacke, Ph.D.NOAA’s Cooperative Center for Marine Animal HealthNOAA’s Cooperative Center for Marine Animal Health
Stress on Coastal EcosystemsStress 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
Why Study Dolphin Health?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
Chemical ContaminantsChemical 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
Coastal Food WebCoastal 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
Biomagnification of Persistent Biomagnification of Persistent Contaminants (Contaminants (e.g.e.g. PCBs) PCBs)
Plankton 0.04 ppm
Small fish 0.2-2 ppm
Largefish
2-8 ppm
Dolphins are top level predators, vulnerable to biomagnification
Dolphins ~10-100 ppm
Organic debris
Bioaccumulation of PCBsBioaccumulation 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
BiotoxinsBiotoxins
• 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
Brevetoxin
• Florida “red-tide”• Neurotoxin shellfish poisoning,
respiratory distress
Source: www.whoi.edu
Panhandle Mortality EventsPanhandle Mortality EventsPanhandle Mortality EventsPanhandle Mortality Events
• 152 dolphins stranded, Aug.1999 – May 2000 • 107 dolphins stranded, Mar. – Apr. 2004, no
observed bloom• 93 dolphins stranded, Sep. 2005 – Apr. 2006
• 152 dolphins stranded, Aug.1999 – May 2000 • 107 dolphins stranded, Mar. – Apr. 2004, no
observed bloom• 93 dolphins stranded, Sep. 2005 – Apr. 2006
0 Cells
1-104 Cells
104 -105 Cells
105 -106 Cells
>106 Cells
Dolphin stranding
K. brevis cell count data
Brevetoxin Related Dolphin Brevetoxin Related Dolphin Mortality EventsMortality Events
Brevetoxin Related Dolphin Brevetoxin Related Dolphin Mortality EventsMortality Events
Texas
Mississippi
Louisiana
Alabama
Florida
1999-2000 (152)2004 (107)2005-2006 (93)
2005-2006 (~200)Multi-species
Gulf of Mexico 1946-1947
Why are dolphins in the Florida Why are dolphins in the Florida Panhandle dying?Panhandle dying?
• Unique exposure pathway/vector?
• Secondary stressor?
Sarasota Charleston IRL Beaufort SJB9000
10000
11000
12000
13000
14000
15000
16000
White Blood Cells (per mL)
Mean Mean±0.95 Conf. Interval
*reported in Hall et al. 2007, Fair et al. 2006, Goldstein et al. 2006
* * *Organic debris
Infectious Disease/PathogensInfectious 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
SummarySummary
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
Sampling MethodsSampling 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
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)