For 40 years, the state has protected manatees by setting up slow speed zones for boaters.

The logic behind it was the same as speed zones around schools: Make people slow down and they're less likely to hit something.

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But in the 1990s, a scientist named Edmund Gerstein announced a startling discovery: Slowing boats down was actually bad for manatees. He said his research on manatees at Tampa's Lowry Park Zoo showed they couldn't hear slow boats, only fast ones.

Boaters and lawmakers were quite taken with Gerstein's study. The state funneled tens of thousands of dollars into more research — which repeatedly contradicted his research. The new research found that manatees don't have any trouble hearing boats. Gerstein faded from prominence.

Now he's back, trumpeting an invention dubbed the "Manatee Alerting Device," or MAD for short. Attached below a boat's water line, the MAD is supposed to blare out a "low intensity, highly directional narrow band of sound" to warn manatees to scatter, according to a press release sent out last month by his employer, Florida Atlantic University.

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He figures that when it's commercially available, the MAD will cost $120. And with 900,000 boats in Florida, he said in an interview that "it'd be great to have one on every boat."

When he heard the news, Alan Huff had this reaction:

"Ohhhh, not that again."

Huff was the state employee who discovered that Gerstein had faked a degree. He said the tens of thousands spent on Gerstein's research was "a waste of money."

And other scientists still don't buy Gerstein's theory.

• • •

Gerstein, 62, grew up in New Jersey. After college in Colorado, he landed a job at SeaWorld as an animal trainer, working with dolphins and whales. Then another marine mammal caught his eye.

"Like everyone I was concerned about manatees, because they were being hit by boats," he said. He wondered if "they weren't getting the information fast enough" to get out of the way.

His initial experiments with Snooty, the beloved manatee who recently died at the South Florida Museum in Bradenton, proved that manatees can be trained to perform certain tasks. Starting in 1991, he focused his efforts on two manatees named Stormy and Dundee at Lowry Park, training them to press a paddle when they heard different sounds.

"My wife and I spent the next three or four years living in a trailer behind the zoo," he said.

Gerstein said his tests proved manatees can hear fast-moving boats better than boats moving more slowly because "they just don't have low frequency hearing."

His conclusion was immediately embraced by boating groups opposed to speed zone regulations that protected manatees. One, Citizens for Florida Waterways, called for using his findings to develop a warning device to be required on every boat.

They also cited his work in a legal challenge to new speed zones and even brought in Gerstein himself to testify as an expert witness. The judge rejected his testimony as lacking credibility.

Meanwhile, follow-up experiments found that Gerstein's conclusions were "really not true," said Doug Nowacek, a Duke University professor who's done extensive studies on marine mammal hearing.

Manatees "are very capable of detecting slower moving boats in general," said Roger Reep, a University of Florida professor who in 2010 co-wrote The Florida Manatee: Biology and Conservation, the definitive book on manatee biology.

The real problem, Reep said, is that in the shallow areas where manatees frequently feed, the sound from boats reverberates and ricochets off everything, making it difficult for them to locate which direction a particular boat is coming from. One study found that, on average, 23 boats an hour passed by a single manatee.

Gerstein admitted that no one has ever reproduced his experiments with the same results, a key test for any scientific theory. He complained that "people didn't want to hear what we were saying."

He blamed that hostility for the 1991 incident involving his resume.

• • •

That year, when Gerstein applied for a federal permit to conduct a manatee study for the Mote Marine Laboratory in Sarasota, he included this line on his resume: "1979. Masters of Science Department of Biology Graduate Program, University of West Florida."

The words "Masters of Science" were underlined.

Huff, now retired, was then the research administrator at the state's Florida Wildlife Research Institute charged with overseeing Gerstein's state-funded research. He discovered Gerstein had no master's degree from UWF. When he confronted him about it, Gerstein had no defense, memos from that time indicate. (Gerstain has since obtained a master's and a doctorate in psychology from FAU.)

When he testified in court later, he dismissed the fake degree complaint by saying he should not have underlined "Masters of Science." In an interview this month, he gave a different explanation.

"I didn't put a comma in the right spot," Gerstein said in the interview. "I don't think that has anything to do with anything."

But Huff said it was a big problem. Without that master's, "he didn't have the kind of background in biological research that you would expect for a research project like this."

Huff informed his bosses via a memo about Gerstein's lack of a degree. Mote took his name off the application and replaced him with someone else — although Gerstein said he did the work.

Neither FAU nor UWF wanted to punish him, Huff said. "They were uninterested in the fact that he had misrepresented his credentials."

A spokeswoman for FAU said current university officials were unaware of the fake degree issue until Gerstein mentioned it to them after speaking to the Tampa Bay Times.

• • •

Now that Gerstein's has re-emerged to plug his $120 MAD devices, his old theory is getting a fresh round of publicity from NBC News and some Florida papers. His fellow scientists still think it's a bad idea, comparing it to putting a siren on every car on a highway.

The aquatic environment is already noisy, Nowacek said. Sticking a MAD on every boat, he said, will make it unbearable for all aquatic creatures, especially the dolphins and manatees that communicate with each other via special noises.

Gerstein is working on another such device, this one for endangered right whales, which migrate between Florida and New England and have been hit from time to time by ships.

Nowacek said the MAD-style beacons would put the whales in greater danger rather than saving them. In a 2004 experiment, he said, scientists blasted a loud noise at whales feeding in deep water.

Instead of scattering, the whales fled to shallower water where they became even more vulnerable to being struck by ships.

"They went from a place that was safe to a place that was unsafe," he said, "and ships still couldn't see them."

Times senior news researcher Caryn Baird contributed to this report. Contact Craig Pittman at craig@tampabay.com. Follow @craigtimes.