Ocean Sentry
Bottlenose Dolphins are a welcome, well-known part of South Florida. But a disturbing increase in dolphin deaths in the Keys has local experts worried. So far, the cause of the dolphin deaths is a mystery. Something is killing members of the pod of dolphins, who live in Florida Bay in the Upper Keys. At least six of the dolphins believed to be from that pod of 50 have been found dead in less than a year. That”s more than 10%, a startling number for local Marine Mammal expert Robert Lingenfelser.
The dolphins all died in 2008. It started in January when the carcass of a young male was found near Long Key. Four months later an adult male turned up near Lignumvitae Key. In June, a male calf was found in Long Key. The next month an adult male surfaced there, and a young male was found the month after that.
In October a year-old male was found floating in Little Buttonwood Sound. A seventh dolphin, a year-old female turned up dead in Key West in November. Experts are waiting for genetic tests to confirm whether she was part of the same Florida Bay pod.
The most frustrating part for Lingenfelser is that despite his 25 years of experience with marine mammals, he can’t figure out why they’re dying.
Lingenfelser and his staff at the Marine Mammal Conservancy in Key Largo performed necropsies, or animal autopsies on each of the dolphins. Most of them died young, though dolphins usually live into their 30s and 40s.
Experts in Virginia Key are examining tissue samples for signs of infection or disease, but Lingenfelser doesn’t believe *disease* is the culprit because most of the dolphins had stomachs full of fish when they died.
“Full bellies tell us this was a healthy, eating animal and something caused it to die really quickly. It doesn’t look like they’ve been sick,” Lingenfelser said.
Experts are looking into whether toxins or other pollutants in Florida Bay are responsible for the deaths. One big snag in that theory though is that fish and other animals have not died in higher numbers in the Bay.
No specific water quality studies have been done as a result of the dolphin deaths, but Lingenfelser is consulting with Florida scientists who regularly test the water, to make sure nothing is out of sorts.
Though experts from the National Marine Fishery Service are looking into the dolphin deaths, they say not enough dolphins have died for them to consider it an “Unusal Mortality Event.” If it is declared “unusual,” that would trigger federal funding and a full-scale investigation.
“Dolphins are important to Florida Bay, think about the circle of life, everything has a purpose and one thing helps maintain control of another,” Lingnenfelser said.
For example, dolphins help maintain the populations of certain species of fish by feeding on those fish, if those fish stocks got out of control, they would overeat smaller organisms and on and on and you could literally crash that circle.”
(From cbs4.com, Key Largo, Florida, by Natalia Zea)
