Second Largest Chelonia Rookery in Brazil. Second Largest Chelonia Rookery in Brazil. The ring-shaped atoll is of volcanic origin, formed by calcareous algae and colonial mollusks. Two small islands, Farol and Cemit rio, are permanently exposed with a total area of 7.2 km 2 . Researchers are sent to the atoll at the end of December, at the start of the nesting season, and remain until July when the last hatchlings emerge from their nests.
Turtles prefer to nest during the high tide to avoid being stranded by the receding waters.
Tidal strandings are rare, but when they occur the turtles must wait for the next high tide to return to the sea. Based on the number of nests laid per month, the peak reproductive period occurs between the months of March and April. The Atol das Rocas Biological Reserve was created in 1979 as the first marine protected area in Brazil. Aside from the second largest nesting population of green turtles in the country, the atoll is also visited by thousands of migratory marine birds, and harbours noteworthy marine biodiversity. For a long time the atoll was a favored area for fishermen, but since 1990 the effective implementation of the Biological Reserve and the constant enforcement of its protected status have guaranteed the area's preservation.