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Tests find lagoon dolphins suffer stomach ulcers
By Jim Waymer
Florida Today
29th February 2004
The stress of lagoon life may be giving dolphins more ulcers than their kin that swim in cleaner waters.
"There appears to be more gastric inflammation in the Indian River Lagoon dolphins," said Greg Bossart, a marine mammal biologist with Harbor Branch Oceanographic Institution in Fort Pierce.
In first year a five-year study, Bossart and his colleagues found early signs of a stomach problem thought to affect only 1 percent to 2 percent of dolphins.
"We're seeing in the Indian River higher than 15 percent," Bossart said.
Last summer, he and several other scientists captured 43 lagoon dolphin and a similar number in Charleston, S.C., to compare the health of the two populations. They tested blubber, skin, blood, urine, faeces and stomach samples.
Early results showed the South Carolina dolphin had healthy cells in their stomach fluid, Bossart said, but several lagoon dolphin had inflamed cells.
"Those can be stomach ulcers or bacterial infections," he said.
The latest finding mirrors what Bossart has seen in recent years in the lagoon dolphin. He's documented diseases thought to be rare or nonexistent in dolphin, such as cancer, hepatitis and heart disease. He's diagnosed meningitis, pneumonia and central nervous systems disorders, including some caused by fungi and protozoa.
Harbor Branch researchers identify some lagoon dolphin by their diseased dorsal fins and torsos covered with knotty cauliflower-like tumours and fungal infections. They suspect a third of the lagoon's estimated 400 to 600 dolphin suffer from such skin disorders.
"When you put all these things together, it starts to suggest that these animals are having some difficulty maintaining their health," Bossart said.
Researchers want to know whether the rate of disease in lagoon dolphin is beyond the norm. The problem is: What's normal?
"An ulcer, that's not at all that unusual," said Dan Odell, a dolphin researcher for Hubbs-SeaWorld Research Institute in Orlando. "It's tough to say exactly what's normal. You just don't know what the situation was 50 years ago."
Odell has noticed a higher rate of deaths since he began tracking the lagoon's dolphin in the late 1970s. But that could be a result of better reporting, he added.
"We see more now, but we have more people out there looking and aware of it," Odell said.
In summer 2001, 35 dolphin died in two months in North Brevard, within about 25 miles of each other. A scientific panel's yearlong investigation found few clues to the cause. They suspected a new red-tide-like toxic algae never before seen in Florida. It may have releasing toxins that built up to fatal levels in the dolphin or caused immune suppression.
The same poison, saxitoxin, made more than 20 people sick who ate puffer fish caught near Titusville that summer. Health officials suspect the same fish caused a Titusville couple to get sick last week, landing the wife in intensive care. The fish remains under a state ban for harvest and consumption.
This past year, 36 dolphin died in the lagoon, down from 38 the previous year. In 2001, the year of the red-tide-like algae bloom, 55 lagoon dolphin died in what the National Marine Fisheries Service dubbed an "unusual mortality event."
The lagoon's top predator is a mammal like us, susceptible to many of the same ills. But scientists have few answers about why lagoon dolphin seem sicker. Theories point to in excess of 10,000 chemicals, including fire retardants and antibiotics that stormwater carries to the food chain.
"DDT and PCBs are in their bodies, but what their doing is not clear," Odell said.
Climate change also may play a role, Bossart said. He points to the global resurgence of 30 human diseases in the past 30 years, including cholera, TB and malaria.
"We're seeing emerging diseases in the ecosystem," he said.
"I'm just seeing a red flag," Bossart added. "I think there's not going to be a single cause and effect."
Contact Waymer at 242-3663 or jwaymer@flatoday.net
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