Harvest of sea turtle eggs was a common occurrence on Guam before World War II. The green sea turtle ("Chelonia mydas") was harvested legally on Guam before August 1978, when it was listed as threatened under the Endangered Species Act. The hawksbill sea turtle ("Eretmochelys imbricata") has been on the endangered list since 1970. In an effort to ensure protection of sea turtles on Guam, routine sightings are counted during aerial surveys and nest sites are recorded and monitored for hatchlings.