Pesticides suspected in Florida gator decline

Deep in the Florida Everglades, biologists are finding some alligators hundreds of pounds underweight

March 15, 1998
Web posted at: 1:12 p.m. EST (1812 GMT)

MIAMI (CNN) -- Researchers in Florida are worried pollutants may be affecting the reproductive systems of alligators, and that if chemicals are responsible for low alligator births, humans could be at risk too.

CNN's John Zarrella tells how sick gators could mean sick people

In 1980, at Lake Apopka near Orlando, Florida, researchers found a correlation between reproductive troubles in alligators and large amounts of pesticides, containing DDT and DDE, that had spilled into the lake.

Reproductive organs were stunted, and testosterone levels were not normal.

"We started to realize that there were large concentrations in the eggs, that the females had accumulated these contaminants," Louis Guillette, a zoologist at the University of Florida, told CNN. ( 119K/10 sec. AIFF or WAV sound)

Zoologist Guillette analyzes alligator weight and reproduction from the finds

Scientists thought the problem may be local, since Apopka was considered an ecological disaster.

Trouble in paradise

But now, researchers have evidence to suggest reproductive troubles may plague alligator habitats throughout the state. What they can't find is a clear cause, like the Apopka chemical spill.

Researchers studied juvenile alligators from Lake Okeechobee, Florida's largest lake. Growth and reproductive hormone levels were severely stunted in 100 juveniles.

In the Everglades, biologists from the University of Miami, are finding alligators maxing out at 200 pounds or less, often hundreds of pounds lighter than alligators in other parts of the state.

In addition, the Everglades alligators are taking 20 years to reach reproductive size, the Miami researchers said.

Researches say pollution is a likely suspect

"There are a multitude of hypotheses," Guillette said.

Among them: changes in diet, changes in nest temperatures, or exposures to pesticides.

But the most likely culprit, researchers say, is pesticides.

Wider implications

Pesticides, fertilizers and phosphorus runoff may be draining into the alligator habitats from nearby agricultural areas.

Researchers say whatever is altering the alligators may affect humans as well.

Because of their place at the top of the food chain, the health of the alligator may be making a strong statement about the health of the environment.

Miami Bureau Chief John Zarrella contributed to this report.

Related sites:

Note: Pages will open in a new browser window

• Fertility on the Brink - The Legacy of the Chemical Age
• A Guide to The Everglades
• Everglades Alligator Farm

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