Dugongs feed on certain types of seaweed. Evidence that dugongs have been feeding on the plants near a U.S. base in the region was spotted by the Okinawa Prefecture Government as recently as 2012, Kyodo News said.
The reclamation project was approved at the U.S. base by American and Japanese officials. It had previously uncovered evidence of dugongs feeding there in June 2009.
Military officials in both countries had approved moving U.S. Marine Corps Air Station Futenma as part of a realignment plan for American forces stationed in Japan. The plan to move the base has met with stiff opposition in Okinawa, where the vast majority of U.S. military installations in Japan are hosted.
Military officials said the dugongs presence will not impact plans to move the base.