The former captain of a Honolulu-based longline fishing vessel admitted in U.S. District Court on Friday to trying to sell shark fins that he knew were illegally harvested in U.S. waters south of Hawaii.

And as part of his plea deal with the government, Matthew Brian Case, 47, accepted his sentence of a $100 fine.

Federal prosecutor Thomas Brady told U.S. Magistrate Judge Kevin S.C. Chang that the government chose to charge Case with a misdemeanor rather than a felony and recommend the $100 fine because Case immediately cooperated with authorities after he was caught, is remorseful and did not intend to profit from the sale of the shark fins. He said Case also agreed to return to Hawaii from his home in Mexico to be prosecuted.

Case told Chang, "I got, cut some fins off a shark, some dead sharks, just to give the crew some extra money. I was going to sell them and give the money to the crew."

He also told Chang he was sorry for what he did.

The government says Case believed he could sell the approximately 100 shark fins to a local hotel restaurant for $600 and tried to do so March 8.

Brady said after the restaurant refused to buy the shark fins, Case left them in a bag on hotel grounds. The fins were not completely dry. Because of the smell, hotel security found the bag and called Honolulu police. Officials at the state Division of Conservation and Resources Enforcement as well as at the National Oceanic and Atmospheric Administration Fisheries were also notified.

The fins came from 23 blue sharks, one oceanic whitetip shark and one silky shark, Brady said.

The government says that during a monthlong fishing trip in February, Case instructed his crew aboard the fishing vessel Hokuao to catch sharks, remove their fins on board, then dispose of the carcasses in the ocean. The practice is known as shark finning.

Federal law prohibits shark finning, having fins that are harvested that way aboard vessels and taking the fins to land.

Hawaii law prohibits having shark fins, selling them or offering them for sale, trade or distribution.