PORTLAND – The Humane Society of the United States and two Maine groups want Saco officials to stop a charity shark-fishing tournament.

“It’s a carnival. It’s a carnival. The sharks are hauled up and kids are given a front-row seat,” said John Grandy, vice president for wildlife at the Washington-based humane society.

The society, the Maine Animal Coalition and the Wildlife Alliance of Maine bought advertising space in a local newspaper and on an airplane banner to coincide with this week’s two-day competition. The groups, which do not plan to picket the event, asked the city’s mayor to cancel the contest.

The Portland Press Herald reported that the campaign is part of a national effort to shut down shark-fishing tournaments.

“The message we need to be sending about sharks is, they’re in trouble worldwide; they need to be conserved,” Grandy said.

The organizer of the Downeast Maine Shark Tournament, a United Way of York County fundraiser that is in its fourth year, said protesters are “going after the wrong people.”

Animal rights groups should use their resources to fight widespread “shark-finning,” a procedure in which a poacher slices off a shark’s dorsal fin for sale as a delicacy, said Dave Johnson, a neuroscientist at the University of New England in Biddeford.

“Recreational fishermen are not the reason sharks are in danger,” Johnson said.

Entrants killed 13 sharks in the first three years of the Saco tournament, he said. Forty teams registered for this year’s contest are bound by a combination of federal restrictions and contest rules to limit their take to one per day.

Remains go to James Sulikowski, a shark, skate and stingray researcher at UNE who uses bones, tissue and organs for studies on age, genetics and population management.

“Without these tournaments, we really wouldn’t know as much as we do about these species,” he said.

Saco Mayor Mark Johnston said he wouldn’t consider closing the event.

“They have a right, it’s legal, and I wouldn’t interfere,” he said.

The tournament, which begins Friday morning and runs until Saturday afternoon, has a $300 entry fee and awards a cash prize using a point system based on weight and type of shark.

The weigh-in station for catches is at the Camp Ellis Pier in Saco.