Stockton Mayor Anthony Silva has asked state officials if Florida manatees could be imported to the Delta to graze on obnoxious water hyacinth.

Give the mayor credit for thinking outside box, one Florida-based aquatic biologist and manatee advocate said Friday.

“Manatees would do a darn good job of eating up hyacinth. They love it,” said Pat Rose, with the Save the Manatee Club near Orlando.

But it’s never going to happen.

Manatees are endangered; there are only about 5,000 left in Florida. So taking the 1000-plus pound, gentle mammals out of their native habitat and placing them into foreign waters would defy all rules and regulations.

And anyhow, the manatees likely wouldn’t survive in the Delta. They live in warm spring-fed waters of at least 68 degrees; in the Delta, water temperatures have already dropped into the low 60s, and it’s not even winter yet.

Exposed to chilly water for a prolonged period, the “sea cows” as they’re lovingly called, would develop lesions that look almost like frostbite. Their digestive systems would begin to shut down.

“They quit feeding and then they essentially starve to death,” Rose said.

Most notably, perhaps, Florida has already tried to use manatees to control hyacinth — and it didn’t work.

In the 1960s scientists put three or four manatees into a canal to see if they could keep hyacinth in check, said Ron Mezich, with Florida’s Fish and Wildlife Conservation Commission.

The sea cows couldn’t keep up with the rapidly spreading plant, despite the fact that a typical manatee eats 50 pounds to 100 pounds of weeds per day.

And so, Florida continues to spray herbicides onto its hyacinth, just like we do in the Delta.

“We spend millions of dollars controlling hyacinth with herbicides,” Mezich said. “Five thousand manatees in the water and we’re still spending millions of dollars.”

Finally, if Delta boaters are frustrated because they must slow down to navigate floating mats of hyacinth, they’d also have to slow down to spare the manatees. Officials in portions of Florida have established speed limits in sensitive habitat areas; speeding boats remain the No. 1 cause of manatee mortality.

Silva wasn’t dissuaded to hear Friday that biologists don’t like his idea. He continues to promote other possible solutions.

Woven furniture like chairs and sofas are commonly made of water hyacinth. Why not offer Stockton’s crop for free to major manufacturers?

“They can have every bit of it,” Silva said Friday.

Or how about using the hyacinth to generate biofuel, a renewable resource?

“I’m just trying to think of everything,” the mayor said. “You know darn well there’s got to be uses for that stuff.”

Rose, the aquatic biologist and manatee advocate from Florida, suggested Stockton would be better off tackling the root of the problem, so to speak — high levels of nutrients in the water that allow the plant to thrive.

In the Delta, nutrients come from sources such as farms (fertilizer runoff) and from wastewater treatment plants, among other places. Of course, the drought and a warm summer have also played a role in this record hyacinth crop.

“You’ve got to stop it at the source,” Rose said.

Contact reporter Alex Breitler at (209) 546-8295 or abreitler@recordnet.com. Follow him at recordnet.com/breitlerblog and on Twitter @alexbreitler.