Green sea turtles have had their ups and downs. They were so plentiful that they were commercially harvested for hundreds of years in the Atlantic, but are now listed as threatened or endangered under the Endangered Species Act, depending on the location.

They were one of the first species to be protected by regulations. That was in Bermuda in the 1600s. Apparently the effort didn’t work, however, as that local population was exterminated.

These days, however, their numbers are increasing. In the Archie Carr National Wildlife Refuge, just below Cape Canaveral, they are having a record year. Researchers and students at the University of Central Florida’s Marine Turtle Research Group counted 12,804 nests as of Thursday in the 13 miles of the refuge’s beaches that they monitor. That’s the first time the number has topped 12,000, said Kate Mansfield, who leads the group.

That’s at least 25 percent of the green sea turtle nests in the United States, and the result will probably be more than 700,000 hatchlings emerging, Dr. Mansfield said.