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

EcoHealth volume 1, pages 246–254 (2004)Cite this article

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.

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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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Authors and Affiliations

  1. Sarasota Dolphin Research Program, Chicago Zoological Society, c/o Mote Marine Laboratory, 1600 Ken Thompson Parkway, Sarasota, FL 34236

    Randall S. Wells

  2. Mote Marine Laboratory, 1600 Ken Thompson Parkway, Sarasota, FL 34236

    Howard L. Rhinehart

  3. US Fish and Wildlife Service, Stockton, CA 95205

    Larry J. Hansen

  4. Dolphin Quest, 4467 Saratoga Avenue, San Diego, CA 92107

    Jay C. Sweeney & Rae Stone

  5. Bayside Hospital for Animals, 251 N.E. Racetrack Road, Fort Walton Beach, FL 32547

    Forrest I. Townsend

  6. Long Marine Laboratory, University of California, Santa Cruz, CA 95060

    David R. Casper

  7. Inter-American Tropical Tuna Commission, c/o Scripps Institute of Oceanography, La Jolla, CA 92037

    Michael D. Scott

  8. National Marine Fisheries Service, Beaufort, NC 28516

    Aleta A. Hohn

  9. National Marine Fisheries Services, 1315 East-West Highway, Silver Spring, MD 20910

    Teri K. Rowles

Authors
  1. Randall S. Wells
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  2. Howard L. Rhinehart
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  3. Larry J. Hansen
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  4. Jay C. Sweeney
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  5. Forrest I. Townsend
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  6. Rae Stone
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  7. David R. Casper
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  8. Michael D. Scott
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  9. Aleta A. Hohn
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  10. Teri K. Rowles
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Correspondence to Randall S. Wells.

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Wells, R.S., Rhinehart, H.L., Hansen, L.J. et al. Bottlenose Dolphins as Marine Ecosystem Sentinels: Developing a Health Monitoring System. EcoHealth 1, 246–254 (2004). https://doi.org/10.1007/s10393-004-0094-6

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  • DOI: https://doi.org/10.1007/s10393-004-0094-6

Keywords

  • bottlenose dolphin
  • ecosystem health
  • sentinel species
  • risk assessment