EcoHealth

, Volume 1, Issue 3, pp 246–254 | Cite as

Bottlenose Dolphins as Marine Ecosystem Sentinels: Developing a Health Monitoring System

  • Randall S. Wells
  • Howard L. Rhinehart
  • Larry J. Hansen
  • Jay C. Sweeney
  • Forrest I. Townsend
  • Rae Stone
  • David R. Casper
  • Michael D. Scott
  • Aleta A. Hohn
  • Teri K. Rowles
Special Section: Marine Sentinel Species

Abstract

Bottlenose dolphins (Tursiops truncatus), as long-lived, long-term residents of bays, sounds, and estuaries, can serve as important sentinels of the health of coastal marine ecosystems. As top-level predators on a wide variety of fishes and squids, they concentrate contaminants through bioaccumulation and integrate broadly across the ecosystem in terms of exposure to environmental impacts. A series of recent large-scale bottlenose dolphin mortality events prompted an effort to develop a proactive approach to evaluating risks by monitoring living dolphin populations rather than waiting for large numbers of carcasses to wash up on the beach. A team of marine mammal veterinarians and biologists worked together to develop an objective, quantitative, replicable means of scoring the health of dolphins, based on comparison of 19 clinically diagnostic blood parameters to normal baseline values. Though the scoring system appears to roughly reflect dolphin health, its general applicability is hampered by interlaboratory variability, a lack of independence between some of the variables, and the possible effects of weighting variables. High score variance seems to indicate that the approach may lack the sensitivity to identify trends over time at the population level. Potential solutions to this problem include adding or replacing health parameters, incorporating only the most sensitive measures, and supplementing these with additional measures of health, body condition, contaminant loads, or biomarkers of contaminants or their effects that can also be replicated from site to site. Other quantitative approaches are also being explored.

Keywords

bottlenose dolphin ecosystem health sentinel species risk assessment 

Notes

Acknowledgments

Veterinary examinations and sampling were conducted through the support of the National Marine Fisheries Service, the U.S. Environmental Protection Agency, the National Science Foundation, Earthwatch Institute, Dolphin Quest, and the Chicago Zoological Society. W. Jarman, J. (Vedder) Greene, and associates conducted preliminary analyses of contaminant levels in blood and milk samples. The participation of J. Buck, C. Driscoll, J. Reif, and G. Worthy in the 1993 Bottlenose Dolphin Health Assessment Workshop provided valuable input for development and evaluation of the approach. The field sampling in Sarasota Bay benefited greatly from the efforts of B. Irvine, L. Fulford, K. Urian, S. Hofmann, K. Hull, and S. Nowacek, along with a host of collaborating researchers and volunteer dolphin handlers. This research was conducted under Scientific Research Permits Nos. 417, 655, 945, and 522-1569 issued by the National Marine Fisheries Service.

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Copyright information

© EcoHealth Journal Consortium 2004

Authors and Affiliations

  • Randall S. Wells
    • 1
  • Howard L. Rhinehart
    • 2
  • Larry J. Hansen
    • 3
  • Jay C. Sweeney
    • 4
  • Forrest I. Townsend
    • 5
  • Rae Stone
    • 4
  • David R. Casper
    • 6
  • Michael D. Scott
    • 7
  • Aleta A. Hohn
    • 8
  • Teri K. Rowles
    • 9
  1. 1.Sarasota Dolphin Research ProgramChicago Zoological SocietySarasota
  2. 2.Mote Marine LaboratorySarasota
  3. 3.US Fish and Wildlife ServiceStockton
  4. 4.Dolphin QuestSan Diego
  5. 5.Bayside Hospital for AnimalsFort Walton Beach
  6. 6.Long Marine LaboratoryUniversity of CaliforniaSanta Cruz
  7. 7.Inter-American Tropical Tuna CommissionLa Jolla
  8. 8.National Marine Fisheries ServiceBeaufort
  9. 9.National Marine Fisheries ServicesSilver Spring

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