Tourists love watching sea otters (search) swim and frolic but under the surface, they're a voracious predator. And that's bad news for commercial fishermen.

"When they come into an area, they decimate all shellfish. No matter what kind, they are going to eat them all," said Mike McCorkle, a fisherman in Santa Barbara, Calif.

Otters eat about 25 percent of their body weight in shellfish a day — as much as 17 pounds.

For the last 18 years, Santa Barbara has been part of an otter-free zone, extending from San Francisco to Mexico. The federal government operated a relocation program where otters found in coastal waters would be taken to an island about 30 miles offshore. But the government now admits the program has been a failure.

Click in the video box to the right for a complete report by FOX News' William LaJeunesse.

The policy was supposed to protect otters from a catastrophic oil spill like that of Exxon Valdez (search). It didn't work because otters kept swimming back from where they came from.

"Other than a few things we learned from it, it never should have been started," said Bob Ferris of the Community Environmental Council.

Ending the relocations will save millions of dollars but Central California fisherman say it could cost them their jobs because they can't compete with a protected species. Environmentalists (search) claim otters aren't the problem.

"They [fisherman] are over-fishing and the resource is dwindling," Ferris said. "If you look at the curve, that fishery is going down already, whether the otter is there or not."