NCCOS Project Explorer (NPE)

Assessment of health and toxin exposure for bottlenose dolphins in an estuary proximate to a National Priority List (NPL) site and Sapelo Island NERR(2010)

Project Description:
The Turtle/Brunswick River estuary (TBRE) near Brunswick, Georgia provides habitat for both a putative resident stock and a coastal migratory stock of bottlenose dolphin (Tursiops truncatus). There is concern for the health of dolphins in this area due to elevated levels of polychlorinated biphenyls (PCBs), mercury and other contaminants which have been reported in soil, sediments, and biota (Kannan et al. 1997, Kannan et al. 1998, Maruya & Lee 1998, Maruya et al. 2001, Pulster et al. 2005). This project will investigate the exposure and potential health effects of PCBs, Hg and other anthropogenic stressors on dolphins along the Georgia coast. Samples of dolphin skin and blubber will be obtained that allow for chemical analyses to determine the dolphins’ exposures to contaminants, as well as genetic analysis to determine sex and to define and delineate stocks. Sampling of dolphins will also be conducted near Sapelo Island, approximately 20 miles northeast of Brunswick. The estuary encompassing Sapelo Island is part of a network of protected areas, the National Estuarine Research Reserve System (NERRS), and as such is a focus site for long-term research and monitoring by NOAA and its partners. The sampling of dolphins in the Sapelo Island area will provide information on contaminant exposures of a top level-predator within this high priority NERRS site. The contaminant exposure of dolphins within the Sapelo Island Reserve is of particular interest given the close proximity of this pristine estuary to the highly contaminated Brunswick area and the potential range of movements for bottlenose dolphins. A study of resident dolphins in nearby Hilton Head Island, South Carolina reported home ranges between 14.7-65.8 km2 (Gubbins 2002). Therefore, it is possible that some dolphins move between the two systems and that dolphin blubber samples from the Sapelo Island estuary may show high concentrations of PCBs and other contaminants as well. The primary objectives proposed for this project are: 1. Provide information on health/exposures of top level predator in two ecosystems that are a focus for NOAA/EPA monitoring of coastal condition (Brunswick area) and a part of a NERRS (Sapelo Island area) 2. Characterize exposures of resident and migratory dolphins to identified coastal pollutant sources along the Georgia coast 3. Evaluate the consistency of health/exposure data for dolphins, a proposed sentinel species, in relation to other indicators of ecological condition for a highly polluted coastal area and an adjacent NERRS site 4. Initiate epidemiological investigations to determine potential health impacts of PCB and mercury exposures on coastal marine mammals.

Expected Outcome:
The National Centers for Coastal Ocean Science (NCCOS) FY05-09 Research Activities as outlined by the NCCOS Strategic Plan include integrated assessments of NERRS. More specifically, an NCCOS project has already been initiated to assess the ecological condition of the Sapelo Island NERRS. Bottlenose dolphins represent a top-level predator and an important ecological resource within the Sapelo Island NERRS and their health and contaminant exposure is one indicator for the status of the ecosystem as related to NCCOS Strategic Goal 1.2. The concurrent assessment of dolphin exposures and other ecological indicators will provide insight into contaminant transport in the food-web and will allow for the evaluation of whether dolphins, a very mobile and often wide-ranging species, provide information on ecosystem condition that is consistent or supplemental to other ecological indicators (relates to NCCOS Goal 1.1). Furthermore, exposure and risk assessment modeling being proposed under this project provide science to support ongoing waste site assessment activities and therefore address NCCOS Strategic Goal 2.3. The proposed project will also address mandates under the Marine Mammal Protection Act to determine health trends in marine mammal populations and correlate such trends with environmental parameters. Dolphin health and exposure data will be collected from two important sites, a NERRS and a nearby estuary proximate to multiple EPA National Priority List sites with known PCB and mercury contamination issues. The data collected from this proposed study, together with dolphin health data from other coastal sites (in the National Marine Animal Health Database) will provide an unprecedented opportunity for epidemiological studies to investigate contaminant concentrations and associated health effects in bottlenose dolphins.