OREGON CITY, Ore. -- Oregon fishermen returning to their cars after a long day of fishing have found their trucks' catalytic converters missing in recent weeks.

Thieves have stolen the converters from trucks parked near popular fishing spots. One of the thefts took place at Clackamette Park, where the Clackamas River meets the Willamette River in Oregon City.

Police said thieves take converters because they contain precious metals, like platinum, that can be sold for quick cash.

Fishermen at Clackamette Park haven't been the only anglers on the lookout for converter thieves. The popular Oregon fishing Web site IFish.net has had dozens of posts from people who have lost their catalytic converters while they were out catching fish.

"Fishermen are a fraternity unto themselves," said Craig Cliff, an avid angler. "We watch out for each other."

Cliff said the warnings from his fellow fishermen about converter thefts won't keep him from coming to his favorite fishing hole.

"If you fish, you're going to go no matter what," he said.

Oregon City police said they've seen a significant increase in converter thefts this spring. So far, just one of the thefts happened at Clackamette Park.

Anyone with information on who is responsible for the recent Clackamette Park theft is asked to call police.

Fishermen Finding Car Parts Stolen