SAN FRANCISCO -- A federal appeals court in San Francisco took a Hong Kong seafood company off the hook Monday from being sued by the U.S. government for a cargo ship's purchase of 32 tons of shark fins on the high seas.

The 9th U.S. Circuit Court of Appeals said that a federal law, the Shark Finning Prohibition Act, didn't give the Hong Kong firm adequate notice that its cargo ship would be considered a fishing vessel for purposes of the law.

The law, passed by Congress in 2000, prohibits activities that aid the practice of shark finning. Banned activities include possessing shark fins on a fishing vessel.

The company, Tai Loong Hong Marine Products Ltd., in the summer of 2002 chartered an American cargo ship that picked up the 32 tons of shark fins from 20 other vessels on the high seas. The company's plan was to deliver the fins to Guatemala.

U.S. Coast Guard officials boarded the ship, escorted it to San Diego and sought to confiscate the cargo, valued at $619,000, on the ground that the law had been violated.

But the appeals court said the law doesn't give notice that a cargo ship would be considered a fishing vessel aiding in shark finning.

Shark fins are sought after for the traditional Chinese delicacy of shark fin soup. Shark finning is the practice of taking fins off sharks and throwing the carcasses back into the ocean, sometimes while the sharks are still living.

Congress said its purpose in passing the law was to "eliminate the wasteful and unsportsmanlike practice of shark finning." The law prohibits possession of fins without the shark carcasses on fishing vessels.