The 71-year-old Wilde was fined $2,500 in federal court. Wilde had spent $40,000 in his own defense, the Fairbanks Daily News-Miner reported.
In September 2010, Wilde was arrested after he told two park rangers he felt it was unsafe to board his boat in the middle of the river for a safety check. He cursed at them and continued upstream.
The rangers drew firearms and threw Wilde to the ground just after he set anchor. He spent four days in jail.
He was found guilty by U.S. Magistrate Judge Scott Oravec of not following orders from a park ranger, interfering with a government agent and having an unregistered boat. Oravec acquitted him on a fourth charge of disorderly conduct.
"We are here today because of your actions and the consequences of your actions," Oravec told Wilde.
Bill Satterberg, Wilde's attorney, said an appeal is possible on the issue of whether federal park rangers have police powers on the river.
He also referred to bills now in Congress that would prevent the Park Service from conducting boat inspections on the river. The bills are sponsored by Alaskans Rep. Don Young and Sen. Lisa Murkowski, who have criticized the park rangers' actions in stopping Wilde.
Murkowski has said the case served as a powder keg because of "the growing frustration Alaskans have with the unprecedented overreach of federal land managers."
State officials believe Alaska has sovereign rights over its navigable waters -- even those that pass through federal lands. But Oravec rejected the state's contention, at least as it concerns regulation of the water surface inside Park Service boundaries.
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