Navigating thousands of miles in the ocean, Olive Ridley turtles have started arriving at Odisha's Gahirmatha beach here in large numbers, marking the beginning of their annual breeding season, a forest official said. The beach, close to the missile test range centre at Wheeler's Island, is one of the largest rookeries of the endangered sea creature, he said. "The mass nesting, a phenomenon known as arribada (a Spanish term), began Tuesday night. An estimated 92,053 female turtles were spotted digging pits with flippers to lay eggs," said Bimal Prasanna Acharya, the divisional forest officer, Rajnagar Mangrove (wildlife) Division. A 600-metre net barricade has been set up on the beach to ensure safety of the turtles. "The forest officials are keeping a close watch on the beach to prevent dogs and jackals from venturing into the nesting ground. As the site is close to the missile test range, visitors are also barred from entering the area," the official said. The mass nesting is expected to continue for another five to six days, he said. "On an average, an Olive Ridley turtle lays about 120 to 150 eggs, which usually hatch after 45-50 days. The hatchlings then emerge from the nests and make their way to the sea," Acharya stated. With the climate being conducive and the beach topography ideal, the turnout of these marine creatures is expected to rise in the coming days, he added.