Echinometra lucunter Linnaeus, 1758 is a tropical sea urchin with strong bioerosive potential. Consequently, this species has great ecological importance. The species occurs in high densities along the Brazilian coast, particularly in the south and southeast. The objective of this work was to evaluate both the effects of annual seasonality and the lunar cycle on the reproduction of E. lucunter. Individuals were sampled monthly for a period of one year and during four complete lunar cycles. The gonadosomatic index (GI) was calculated to determine the annual and monthly reproductive peaks based on the lunar phase. The sex ratio (male:female) was 1:1.04, without significant difference in sexual proportion. The GI was significantly higher for males than for females. The first sexual maturation occurs when carapace width reaches 23.30 mm, and 50% of the animals have gonads with 28.22 mm. The spawning peak generally occurs during the whole year from the full moon to the waning moon. However, there is an annual reproductive peak from summer to autumn.
Gonadosomatic Index; lunar periodicity; sazonality; sea urchin
