A Honolulu-based bottom-fishing vessel was ordered to return to port last week and faces possible civil penalties after it was allegedly caught fishing in a restricted area of the Northwestern Hawaiian Islands Marine National Monument.

A Coast Guard search plane on patrol of the Papahanaumokuakea Marine National Monument spotted a U.S.-flagged vessel fishing in a special preservation area within the monument on June 15. The Coast Guard said it took video and still photos of the vessel's crew hauling its lines out of the water and the ship then "abruptly getting underway."

The aircraft flew out of sight, but when it returned the vessel's crew had put its lines back in the water and resumed fishing, the Coast Guard said. The incident was reported to the National Oceanic and Atmospheric Administration's Office of Law Enforcement, which ordered the vessel to cease fishing and return to Honolulu.

The name of the vessel, which reached port on Saturday, was not released because the case is under investigation. The vessel's owner faces charges of illegally fishing in the national monument and fines from $1,000 to $130,000 for a repeat offense.

Papahanaumokuakea spans nearly 140,000 miles and is the largest marine protected area in the world. The Northwestern Hawaiian Islands chain is home to more than 7,000 marine species and is the primary habitat for critically endangered Hawaiian monk seals and green sea turtles.

Although Papahanaumokuakea is a protected area, eight fishing vessels are allowed to fish within the monument. But there are "special preservation areas" where no fishing is allowed and that was where the vessel was spotted, said Bill Pickering, Office of Law Enforcement special agent in charge.

Pickering would not comment on the details of the case while it remains under investigation. But he did say that the vessel is one of the eight permitted to fish in the monument.

"But even inside the monument there are areas that are very protected and the alleged violation here is that it was fishing in one of those protective areas," Pickering said.

Lt. John Titchen, Coast Guard spokesman, said it was the fourth time that the Coast Guard has caught a vessel fishing within the monument since it was dedicated in 2006.