Panulirus echinatus population in the Brazilian oceanic ecosystem Rocas Atoll

In Rocas Atoll (03 degrees 51'S 033 degrees 48'W) a most abundant population of Panulirus echinatus Smith, 1869 was observed during free dives. Numbers of males and females were almost the same, with an overall sex ratio M : F = 1.1. In addition, males are larger than females, with a mean male carapace length (CL) of 92.6 +/- 1.8 mm, while the female mean CL was 72.7 +/- 1.0 mm and for both sex combined the mean CL was 83.1 +/- 1.4 mm. The percentage of females breeding, i. e., with a spermatophore mass or eggs, was 75.1%. More information is needed to better understand the fluctuation in densities over a year cycle, the reproduction period, and differences in CL between males and females, as well as other aspects of the biology of this species. The present work and future information could help to formulate fisheries policies aimed at protecting P. echinatus stocks.