>>> finally tonight one of the great success stories the world of wildlife. the return of green sea turtles to the coast of florida , decades after they were placed on the endangered species list . there was an increase in nesting this year capping a remarkable recovery. here's nbc's mark potter .  >> reporter: on a remote beach on the east coast , newly hatched green turtles struggle toward the water's edge to begin life at sea. once faced with extinction, green turtles are now on a remarkable comeback, a success story cheered by environmentalists.  >> they are majestic, charismatic animals that intrigue us. the world would be a poorer place without them.  >> reporter: they eat sea grass and adults can weigh more than 400 pounds n. the spring females dig nests in the sand to lay their eggs which hatch nearly two months later. because they are easily captured green turtles were long harvested for food and nearly disappeared.  >> we ate a lot of them, almost all of them.  >> reporter: in 1978 the u.s. added green turtles to the endangered species list . biologists counting turtle nests at the archie carr national wildlife refuge in florida are astounded by the results. there were only 62 nests in 1979 . there are 35,000 this year. it can take green turtles 30 to 40 years to mature and begin building nests like this which is why scientists say it's taken so long since they were put on the endangered species list to see such positive results now. green turtles face other threats such as fishing lines, hooks and nets. at the turtle hospital in the florida keys , many are treated for aggressive viral tumors. the cause? unknown.  >> we have so many more, higher percentage coming with tumors all over them. it gets on their eyes so they can't see and they starve.  >> reporter: rising ocean levels and sea walls will destroy their nesting sites.  >> every day twice a day at high tide the beach will be covered with salt water .  >> reporter: still, the nesting explosion now is seen as a hopeful sign that conservation measures can work to restore a valued species that nearly went away. mark potter , nbc news, melbourne beach , florida .
Video on msnbc.com: After coming close to extinction, nesting for green sea turtles has seen a major increase in Florida. NBC’s Mark Potter reports.