The manatee lay still, floating in the shallow waters of a Florida river over the weekend when a woman on a boat noticed something odd. As she moved closer and filmed with her phone, Hailey Warrington found a one-word message scrawled on the marine mammal’s back: “TRUMP.”

“This is just disturbing. One hundred percent disturbing,” Warrington, who discovered the defaced manatee in the Homosassa River, told the Sarasota Herald-Tribune.

Now federal and local authorities are investigating who is responsible for etching the president’s name on the threatened animal’s back. Harassment of a manatee is a criminal offense punishable by a $50,000 fine and up to a year in prison.

“Endangered species are not billboards to be defaced,” Jaclyn Lopez, Florida director at the Center for Biological Diversity, told The Washington Post in an email. “What happened to that manatee was wrong and unlawful, and the guilty party should be held accountable.”

In 1973, manatees were first classified as endangered under the Endangered Species Act. Although the aquatic mammals have since been upgraded to a “threatened” status, scientists say the creatures continue to face serious danger. Each year, about 100 manatees die of collisions with boats, which account for about 20 percent of manatee deaths. Florida is home to more than 6,300 West Indian manatees, according to the U.S. Fish and Wildlife Service.

Each winter, an influx of manatees seeking warmer waters arrive at the Citrus County coastline, the Citrus County Chronicle reported.

Warrington was operating a manatee boat tour on Sunday when she noticed the sleeping animal. The layer of algae covering the manatee’s skin was “pretty thick,” she told the Herald-Tribune, noting that while the message had been scraped down to the level of its skin, it didn’t appear to have left a wound.

“We don't typically see manatees harassed like that,” she told the local paper. “I started documenting so we could report it.”

Shortly after spotting the creature, Warrington said she sent video to authorities.

On Monday, the Center for Biological Diversity announced a $5,000 reward for anyone with information leading to a conviction. The U.S. Fish and Wildlife Service and Florida’s Fish and Wildlife Conservation Commission also opened investigations.

“However this political graffiti was put on this manatee, it’s a crime to interfere with these creatures, which are protected under multiple federal laws,” Lopez said in a statement.

A spokesperson with the U.S. Fish and Wildlife Service told The Post that the manatee does not appear to have suffered any serious injuries “as it seems that the word was written in algae on the animal’s back.”

“West Indian manatees are essential members of the ecosystems in which they inhabit and are protected under the Endangered Species Act and the Marine Mammal Protection Act,” said Aurelia Skipwith, director of the U.S. Fish and Wildlife Service, in a statement. “The U.S. Fish and Wildlife Service is aware of this incident and is working closely with the Florida Fish and Wildlife Conservation Commission.”

Elizabeth Fleming, senior Florida representative for the Defenders of Wildlife, said she was taken aback when she saw images of the manatee.

“Politics, as ugly as it has gotten, we need to do better at working it out among ourselves,” Fleming told The Post in an interview. “This animal has nothing to do with politics. This animal is just trying to live its life.”

Fleming said she suspects the person responsible either restrained the manatee or found a manatee so used to human interactions that it didn’t fight. Either way, leaving a message on the manatee’s back was a crime, she said.

“Somebody was trying to make some kind of statement and what they did to this manatee is not a lawful act,” she said. “You are not allowed to harass manatees, and this is what this was.”