Abstract

The Health and Risk Assessment project (HERA) was initiated in 2003 by Harbor Branch Oceanographic Institution and the National Ocean Service, Center for Coastal Environmental Health and Biomolecular Research to study the Atlantic bottlenose dolphin (Tursiops truncatus) populations inhabiting the Indian River Lagoon (IRL), Florida and the coastal waters of Charleston, South Carolina (CHS). This five year project is a comprehensive integrated, multidisciplinary research project designed to assess environmental and anthropogenic stressors on Atlantic bottlenose dolphins (Tursiops truncatus), as well as the health and viability the IRL and CHS populations (Bossart et al, 2006). During the 2003-2006 project years, a total of 221 dolphins have been safely captured and released from the IRL and CHS waters. The HERA project has included contributions from over twenty scientific research organizations and universities, numerous marine parks, marine mammal veterinarians and veterinary students from around the world. In addition, numerous peer-reviewed publications have been produced with data and samples collected from the HERA project. This abstract focuses specifically on preliminary findings from the IRL portion of the study.

The IRL is the most biodiverse coastal estuary in North America (Gilmore 1985) and was designated an Estuary of National Significance in 1990 (IRLNEP, 1996). Prior to the initiation of the HERA project, no comprehensive health assessments of bottlenose dolphins have been conducted within the IRL. In 1979-1981 a study of IRL dolphins involved the freeze branding and monitoring of those marked animals, mostly within the northern section of the IRL (Odell and Asper, 1990). The population of IRL dolphins has recently experienced an unusually high incidence of infectious diseases of the skin and other organs. In necropsies of dolphin carcasses recovered in the IRL, Bossart et al. (2003) reported a high prevalence of infectious and inflammatory disease of the skin and other organs that were consistent with a state of immune compromise including lobomycosis which has been previously associated with immunologic suppression in bottlenose dolphins (Bossart, 1984).

Emerging diseases of marine mammals are issues of concern in the IRL (Bossart et al., 2003). Numerous preliminary findings have caused reason for concern of the health status of the IRL dolphin population. From 2003-2005, 90 individual dolphins were sampled from the IRL. Infectious diseases such as lobomycosis are present in epidemic proportions (Reif et al., 2005). Between 2003 and 2005, 9 of the 90 dolphins had evidence of lobomycosis. All affected dolphins were captured in the southern portion of the IRL. During the same time period, 2 dolphins had oral papillomas and 10 had genital papillomas (12/90 = 13.3%). The prevalence of oral/genital papillomas increased dramatically in each year of sampling. In 2003, there were no affected dolphins, while in 2004 and 2005 the prevalence was 10% and 42%, respectively (Bossart et al. 2005). Other findings include a high prevalence of gastric inflammation as well as pox virus.

Dolphin health and population status in the IRL reflect the effects of natural and anthropogenic stressors and may serve as a sentinel for ecosystem health (Bossart, 2005a). Defining the health status of bottlenose dolphins is important for future management of this species and provides an insight into the ecosystem as a whole (Bossart, 2005b).

Acknowledgements

This work was conducted under National Marine Fisheries Permit No. 998-1678-00, issued to Gregory Bossart, V.M.D., Ph.D. of Harbor Branch Oceanographic Institution in March 2003. The HERA project is a collaborative effort between Harbor Branch Oceanographic Institution and the National Ocean Service, Center for Coastal Environmental and Biomolecular Research, NOAA. Mr. Wayne McFee performed analyses of dental enamel to estimate age. Dr. Forrest Townsend conducted physical examinations and Larry Hansen was responsible for field coordination during captures. The authors thank the entire HERA staff and the Harbor Branch Marine Mammal volunteers for their efforts. Funding was provided from the Protect Wild Dolphins License Plate Fund and the NOAA Fisheries Marine Mammal Health and Stranding Response Program.

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