The Georgia Dolphin Health Assessment capture-release study provides information on the health of the wild dolphin population that inhabits estuaries along the Georgia coast.
A panel of governmental, academic and non-profit scientists speaking at the annual meeting of the American Association for the Advancement of Science (AAAS) unveiled research suggesting that diseases found in dolphins are similar to human diseases and can provide clues into how human health might be affected by exposure to contaminated coastal water or seafood.
“Dolphins and humans are both mammals, and their diet includes much of the same seafood that we consume. Unlike us, however, they are exposed to potential ocean health threats such as toxic algae or poor water quality 24 hours a day,” said Carolyn Sotka of the NOAA Oceans and Human Health Initiative and lead organizer of the session. “Our ecological and physiological similarities make dolphins an important ‘sentinel species’ to not only warn us of health risks, but also provide insight into how our health can benefit from new medical discoveries.”
“Marine animal and ecosystem health are connected to public health and well-being,” said Jane Lubchenco, Ph.D., under secretary of commerce for oceans and atmosphere and NOAA administrator. “NOAA is committed to better understanding these connections and building the partnerships necessary to have healthy oceans, including healthy dolphins.”
NOAA is the principal stewardship agency responsible for protecting dolphins in the wild and supports a network of national and international projects aimed at investigating health concerns. A few of these case studies highlighted February 18 at AAAS illustrate how studying disease processes, or pathologies in dolphins, could lead to future prevention or treatment of some diseases in humans. Equally important is the knowledge gained with regards to overall population health, which can lead to improved management and science-based guidelines to mitigate disease outbreak in both people and animals.
Unprecedented Contaminant Levels in Coastal Dolphins Warn of Potential Health Risks
Researchers from NOAA and its partner institutions recently discovered that bottlenose dolphins inhabiting estuaries along the Georgia coast have the highest levels of polychlorinated biphenyls (PCBs) ever reported in marine wildlife. The term PCB encompasses a suite of persistent contaminants that have been banned in the United States since the late 1970s due to documented adverse health effects. The extraordinarily high levels of PCBs measured in the dolphins, a maximum concentration of 2900 parts per million, may be suppressing their immune function.
The unique signature of the PCB compounds found in these dolphins is consistent with contaminants of concern at a Superfund site near Brunswick, Ga. Scientists are equally concerned about the high PCB levels in dolphins sampled near a marine protected area approximately 30 miles from Brunswick. This suggests that the contaminants are moving along the coast through the marine food web.
“When we received the lab results for the Georgia dolphins, we were alarmed by the contaminant levels and set out to investigate how these heavy chemical burdens were affecting their health,” states Lori Schwacke, Ph.D., with NOAA’s Center for Oceans and Human Health at the Hollings Marine Lab and co-lead investigator on the team.
Last August, the team conducted a dolphin ‘capture-release medical physical’ on this population and found decreased levels of thyroid hormones, elevated liver enzymes and indications of suppressed immune function.
A pilot study is being undertaken by the National Center for Environmental Health, Centers for Disease Control and Prevention (CDC), to examine potential environmental contaminants in residents of nearby coastal communities. The researchers are investigating whether coastal dolphin populations and human communities sharing the same seafood resources experience similar exposures.
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