Population dynamics and secondary production of Emerita brasiliensis (Crustacea: Hippidae) at Prainha Beach, Brazil

The secondary production and population dynamics of the mole crab Emerita brasiliensis Schmitt, 1935 (Decapoda: Hippidae) were studied by taking monthly samples from June 1993 to May 1995 at each of three intertidal transects at Prainha beach, Brazil. The lifespan was ca. 8 months for males and females, but females showed higher growth, mortality, secondary production, and turnover rate. The higher production in spring versus autumn and winter was related to intense recruitment during that period. The population production was estimated at between 39.86 and 46.88 g (AFDW) . m(-2) . a(-1) for the first year (June 93-May 94) and between 150.95 and 156.07 g (AFDW) . m(-2) . a(-1) for the second year (June 94-May 95); the mean annual biomass was 4.91 and 23.09 g (AFDW) . m(-2), respectively. High P/B rates, between ca. 6 and 9 . a(-1), reflected the fast growth, high mortality, and low lifespan of the population, characterized by a high percentage of recently recruited individuals.