LITTLE ROCK, Ark. — Any expedition in the Buffalo National River area that charges a fee requires a permit from the federal government.

That includes expeditions to find Bigfoot.

That was the message two National Park Service rangers had for Matt Pruitt when they found him and 31 other Sasquatch seekers at the Steel Creek campground near Ponca on Feb. 24.

Pruitt explained that he was leading an expedition for The Bigfoot Field Researchers Organization, which has 24 other expeditions planned this year in the United States and Canada.

The participants in Pruitt’s Arkansas expedition had paid between $300 and $500 apiece to search for Sasquatch, according to a National Park Service incident report from Chief Ranger Karen Bradford. That basically made Pruitt a “concessionaire,” similar to those who rent canoes or operate other businesses in the park, Bradford said.

The rangers, Billy Bell and Ben Henthorne, cited Pruitt for “engaging in a business without a permit or written agreement,” the report stated.

Pruitt said he paid the $525 fine online Friday.

“I think it was a fairly innocent mistake,” he said. “At first they were very concerned that we were filming, that we were trying to get away with commercial filming without a permit. Once those concerns were satiated, there were other concerns.”

Matt Moneymaker, founder and director of The Bigfoot Field Researchers Organization, has a show on the Animal Planet television network called “Finding Bigfoot.” But none of the cast from the show participated in the Arkansas expedition, and no video cameras were taken on the expedition, Pruitt said.

Bradford said she was concerned about the park’s environment.

“We’re not in this to make a lot of money, but we are in this to protect our resources,” she said. “If he’s got people running around in the park, who knows what they’re doing looking for this elusive creature.”

Normally, the group would have been asked to leave the park, but since some had traveled from far away to look for Bigfoot, the park rangers let them stay, Bradford said.

“There was this kid, it was his birthday present to come and look,” she said.

Seventeen participants on the trip paid a total of $3,650, which went to the organization, said Pruitt, who said he was paid half that amount, or $1,825, to lead the expedition.

“I lost money on that particular expedition,” he said.

Pruitt said he will check with rangers before leading another Bigfoot expedition on National Park Service land, which is under the jurisdiction of the U.S. Department of the Interior.

Fees for permits vary depending on use, Bradford said, but Pruitt probably wouldn’t have been granted a permit to lead a Bigfoot hunting expedition in the Buffalo National River area anyway.

“It’s highly unlikely that we would have issued a permit to do that,” she said.

According to the Buffalo National River website, special use permits must be obtained for groups of 26 people or more. Those permits normally cost $150.

“I am not angry in the least,” said Pruitt. “I don’t feel mistreated by the Parks Service. … It was my neglect.”

Other than the fine, Pruitt said things went well during the Arkansas expedition. Pruitt said he has conducted Bigfoot expeditions in 18 states, and he had rank Arkansas in the top three for Sasquatch activity.

“There were certainly things that happened that convinced me that there are sasquatches in the Buffalo River area,” said Pruitt. “We definitely heard sounds that were indicative of Sasquatch. Characteristic vocalizations. Very compelling observations.”

Pruitt was using a thermal imaging device, which is used for night vision, and for the first time, he said, he saw what may have been a Sasquatch.