A Hawaiian monk seal yearling is expected to be transported back to Kauai Friday and returned to the wild after undergoing a successful emergency procedure to remove a swallowed fishhook.

Federal marine officials said the hook was removed with minimal damage on Wednesday at National Oceanic and Atmospheric Administration facilities on Ford Island. "We feel the prognosis is good," said Gregg Levine, the veterinarian surgeon who performed the extraction.

Levine said removing the fishhook took two hours and required anesthesia. He used a miniature video camera to give him a view of the hook inside the seal’s esophagus and a rigid metal instrument that could attach to the hook and slowly extract it from the throat.

"It was quite embedded," Levine said. "It took a lot of effort."

Levine said that since the procedure the male seal had been swimming in a pool Thursday and was able to eat.

The Hawaiian monk seal, or Monachus schauinslandi, one of the rarest marine mammals in the world, is protected as an endangered species.

About 10 to 15 Hawaiian monk seals are found annually with fishhooks that require removal, said Rachel Sprague, Hawaiian monk seal recovery coordinator for the National Marine Fisheries Service. About two are known to die annually due to fishhook injuries, she said.

The U.S. Coast Guard transported the seal via aircraft to Oahu on Tuesday after a community volunteer on Kauai reported seeing it with a hook in its mouth. Sprague said the gear appears to have come from a shoreline fisherman, many of whom fish for ulua.

Overall, the Hawaiian monk seal population has been declining from between 1,500 and 1,600 about 10 years ago to 1,100 to 1,200 this year, she said.

The population has been increasing by about 5 percent a year in the main Hawaiian Islands but decreasing in the Northwestern Hawaiian Islands. She said major factors for decreasing numbers in the Northwestern Hawaiian Islands include low food availability, competition with other predators and entanglement in marine debris.

Interventions by NOAA fisheries and partners include de-hooking, treating diseases, rehabilitating starving seals and surgeries.

"They only exist in Hawaii, which means we have the responsibility of either saving the species or watching them disappear," Sprague said.

"When you’re dealing with a species that’s endangered, every individual matters."