The U.S. Fish and Wildlife Service is investigating the harassment of a manatee discovered with the word "Trump" etched into its back, officials said Monday.

Hailey Warrington found the manatee swimming on Sunday in the Blue Hole headwaters in North Florida. The defacement "is just disturbing. One hundred percent disturbing," she said.

The president's last name may have been written in algae on the marine mammal's back, the Center for Biological Diversity told USA TODAY on Monday night, an act prohibited under the Endangered Species Act.

“Manatees aren’t billboards, and people shouldn’t be messing with these sensitive and imperiled animals for any reason,” Jaclyn Lopez, the center's Florida director, said in a statement. She called it "political graffiti."

Manatees, nicknamed “sea cows” because they eat seagrasses and other aquatic plants, are considered "threatened" by the Fish and Wildlife Service, after previously being classified as "endangered" until 2017.

Video: Massive manatee meets construction workers onsite

“This abhorrent action goes beyond the bounds of what is considered cruel and inhumane," Elizabeth Fleming, a senior Florida representative at Defenders of Wildlife, said in a statement. "I’m disgusted that someone would harm a defenseless creature to send what I can only assume is a political message. We will do everything in our power to help find, arrest and successfully prosecute this coward.”

The Center for Biological Diversity has announced a $5,000 reward for information leading to a conviction in the investigation. The manatee "does not appear to be seriously injured," according to an update provided by federal officials to the Center Monday night.

Still, Lopez said, "It’s heartbreaking that this manatee was subjected to this vile, criminal act."

The manatee appeared to be healthy but was exhibiting stress signs, Warrington said. The layer of algae on the manatee was "pretty thick" and the etching did get to the skin but didn't appear to create a wound.

"We don't typically see manatees harassed like that," she said. "I started documenting so we could report it. That's why I have the photos and video in the first place."

Nearly 600 manatees died in Florida waters in 2020. Here's what the state is doing about it

One can only assume the mammal's defacement was politically motivated, said Elizabeth Neville, senior Gulf Coast representative at Defenders of Wildlife.

But this is far from "the only scar borne by manatees due to politicians’ destructive choices," she said in a statement.

"Other scars include policies that favor unsustainable development and polluting industries, hamper communities’ abilities to address plastic trash in our waters and impede progress on fighting climate change.”

Contributing: Carlos R. Munoz and Jigsha Desai, Sarasota Herald-Tribune

This article originally appeared on USA TODAY: Florida manatee, 'Trump' etched into its back, sparks outcry, probe