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Atol das Rocas (3°52'S, 33°49'W), the only atoll in the South Atlantic Ocean, is located 144 miles off the northeastern coast of Brazil. The ring-shaped atoll is of volcanic origin, formed by calcareous algae and colonial mollusks. Two small islands, Farol and Cemitério, are permanently exposed with a total area of 7.2 km². In 1981, 1982 and 1986, the National Program for the Conservation and Management of Brazilian Marine Turtles (TAMAR Project/ IBAMA) sent expeditions to the atoll to estimate the number of turtles that nested there. After verifying that the atoll is Brazil's second largest reproductive area for green turtles, Chelonia mydas -- the first being Trindade Island (Moreira et al. 1995) a comprehensive program of annual monitoring and data collection began in 1990.

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. Beach patrols are conducted at night and nearly 100% of the nesting females are tagged. 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. During four consecutive seasons of monitoring (1990-1994), TAMAR has documented 3411 nests and tagged 456 nesting females. The mean curved carapace length and width are 118.6 cm (range 100.0 - 134.0 cm, n=1188) and 108.7 cm (range 94.0 - 130.0 cm, n=1188), respectively. Based on the number of nests laid per month, the peak reproductive period occurs between the months of March and April. The nests are left in situ and show a hatch success rate of 75.4%. The average incubation period (egg laying to hatchling emergence) is 61 days (range 51-74 days, n= 153 nests).

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.

Moreira, L., C. Baptistotte, J. Scalfone, J. C. Thomé, and A. P. L. S. de Almeida. 1995. Occurrence of Chelonia mydas on the Island of Trindade, Brazil. Marine Turtle Newsletter 70:2.

CLAUDIO BELLINI, Projeto TAMAR/IBAMA, CP 50, Fernando de Noronha - PE, BRAZIL 53999-000; MARIA ANGELA MARCOVALDI, Fundaçao Pró-TAMAR, CP 2219, Salvador - BA, BRAZIL 40210-970; TAISI MARIA SANCHES and ALICE GROSSMAN, Fundaçao Pró-TAMAR, CP 50, Fernando de Noronha - PE, BRAZIL 53990-000 and GIBERTO SALES, IBAMA, Av. L4 Norte, SAIN, Brazília - DF, BRAZIL 70800-200.