Sunday, May 20, 2007

Indian River Bottlenose dolphins are plagued by sickness

A cigarette butt bounces to the roadway of a bridge over the Indian River Lagoon.Brake dust coats the nicotine-laced piece of trash as vehicles rumble past.

A rain shower washes the noxious throwaway into the watery home of the lagoon's beloved residents -- bottlenose dolphins.The dolphins of the Indian River Lagoon are sick and getting sicker, and not just from such human destruction, but also from a plethora of emerging diseases that have yet to be explained.Harbor Branch Oceanographic Institution has released new data from its lagoon study of dolphin health that shows the percentage of sick animals examined by researchers increased 75 percent from 2003 to 2005.

The numbers could have profound meaning for the health of the lagoon itself, the regional economy and even public well being."We better start to pay attention to this because the same pressures that are causing (dolphin) health issues and seals migrating from the arctic to Florida are the same issues that are eventually going to impact us," said study leader Dr. Gregory Bossart, Harbor Branch's senior scientist and marine mammal veterinarian. "So it's in our best interest to understand it."


Dolphins are barometers of the health of the lagoon Florida residents hold so dear.A sick dolphin means a sick lagoon."The Indian River Lagoon is a huge economic engine that drives the economy of 40 percent of Florida's East Coast," said Steve McCulloch, Harbor Branch's marine mammal stranding program manager. "Eventually the economy will be affected. Think about it. If the water here is unsafe for dolphins, boating, fishing, recreational fishing ... property values all start diminishing.

"And there is a connection between the health of the marine darlings and their human admirers.There have been no recorded cases of humans getting sick from dolphins along the Indian River. But an increase in dolphin disease could be an ominous sign of future health issues in people."The same factors that are allowing these diseases to emerge," Bossart said, "are the same factors that are allowing perhaps our health to be compromised as well. So it's a very complex issue."


That is just one of the questions the dozens of scientists, biologists, experts and students hope the study data will reveal in the coming months and years.Some answers are clear: humans pollute the water.McCulloch said he has found nicotine, brake dust and flame retardant chemicals in dolphins he has examined.Someone who threw away a rubber ring almost caused the death of a young dolphin, had it not been rescued by a Harbor Branch team Thursday.

And there is no question chemicals run off of green residential lawns and the by-products of agriculture and rapid development are finding their way into the water, McCulloch said.But there's a lot about why the dolphins are getting sicker that's just not yet explained.

Bossart believes in a phenomenon called "environmental distress syndrome."He theorizes ecological and climatic factors "are actually encouraging the selection of new pathogens. So new pathogens are occurring."


The lagoon study is an example of the distress syndrome, Bossart said.Two emerging diseases, a chronic fungal skin disease of "epidemic" proportions and oral and genital tumors, are most concerning for researchers.When the study started in 2003, no lagoon dolphins examined by researchers had tumors. In 2004, 11 percent had tumors. In 2005, 47 percent had tumors."One of the top theories is ... these new emerging diseases are actually evolving, related to global climate change," Bossart said.

"So what's happening on this planet is actually encouraging new pathogens to emerge."Bossart and his team firmly agree there is climate change."You have to be in denial to say there is no climate change occurring on this planet," he said. "... But the cause of it is probably still debatable, whether or not it's global warming due to greenhouse gasses or a natural state in this plant's climate history or a combination of both or other things."


Researchers and dozens of collaborators plan to continue their work for another five years after the current study permit ends in January 2008, researchers said.The study, including all the testing and analysis, costs $300,000-a-year and is funded by the sale of specialty marine license plates, McCulloch said.For the longtime marine mammal expert, that's not a lot compared to the possible accomplishments."It's a legacy we pass on to our children," he said.

"Hopefully, through our efforts, we'll leave them some dolphins and clean water and everything else that swims in it."


• Harbor Branch researchers began finding sick dolphins in 2003, while working on a photo-identification study of the animals in the Indian River Lagoon.

• More than 30 percent of the 500 dolphins studied at the time had skin disorders and tumors in the lagoon waterways that cover 168 miles from Cape Canaveral to Jupiter.

• The Harbor Branch team obtained a permit from the National Marine Fisheries Service to begin a five-year study to find out more.

• The main goal was "to identify serious health threats to the animals, such as pollutants, so that effective management plans can be designed."

• Researchers picked two locations -- the lagoon and Charleston, S.C. -- to compare "two distinct populations influenced by very different environmental conditions." That should allow researchers to "zero in on the factors posing the greatest health risks."

• More about the study and how to buy the specialized license plates that fund the work is available at: www.hboi.eduSource: Harbor Branch Oceanographic Institution


• One hundred ninety dolphins were analyzed. Each dolphin was classified as normal, possibly diseased or definitely diseased.

• Researchers found 87, or 45.8 percent, of the dolphins were normal, 52, or 27.4 percent, were possibly diseased and 51, or 26.8 percent, were diseased.

• The prevalence of definite and possible disease was compared among dolphins from Charleston and the Indian River Lagoon. The prevalence of definitely diseased dolphins was higher among dolphins captured in the Indian River Lagoon, 32.3 percent, than among dolphins captured in the waters around Charleston, 20.9 percent.


• Researches found several sicknesses in the dolphins: hepatitis, meningitis, pneumonia, and central nervous systems disorders, among others.

• The teams also found antibiotic resistant bacteria.

• New diseases are emerging at a worrisome rate.

• Sexually transmitted diseases are infecting the dolphin population.

• The illnesses could endanger the dolphins' lives.


• Two emerging diseases were noted: lobomycosis, a skin disease and, orogenital neoplasia, oral and genital tumors.

• The diseases accounted for 31 of the 51 definite disease diagnoses, or 60.8 percent. Eleven of 32 diseased lagoon dolphins had lobomycosis, which occurs in epidemic proportions in the southern lagoon. Lobomycosis was not identified at the Charleston site or in the northern Indian River Lagoon.

• Oral and genital neoplasms occurred in male and female dolphins at both capture sites. The disease was not detected in any of the 2003 captures but was found in 2004 and 2005 at both sites. Thirteen lagoon dolphins and seven Charleston dolphins had evidence of oral or genital tumors.

• For both capture sites, an increase in prevalence of definite disease was observed between 2003 and 2005.


• Dolphins are captured in nets and lifted onto specially designed research ships.

• The exams take less than an hour.

• Scientists document various vital information such as size, weight and age.

• They collect tissue samples, feces, urine, blood and blubber.

• Each animal is tagged for tracking on its dorsal fin.

Quick "Facts about Dolphins"