Produção secundária das espécies mais abundantes da macrofauna bentônica da zona entre-marés da Prainha, estado do Rio de Janeiro

Abstract

With the aim of estimating the secondary production of Emerita brasiliensis and Exciro lanabrailiensis, at Prainha Beach(R), monthly samplings were performed in the period fom June 1 993 to May 1 995. Three transects were established in the intertidal zone, perpendicular to the waterline, each divided into fve strata parallel to the waterline. From each levei, fur replicates were taken using a 0.04 m2 metal sampler. The life span of Emeritabrasiliensis fmales was calculated in 1 0.3 and 8.0 months for the first(93/94) and second(94/95) years, respectively. For the males this parameter was estimated around 9 months for the two years of study. The production was calculated by the methods of Hynes and Crisp 3A, and was estimated between 1 5.589 and 1 2.378g(AFDW)m·-2a·-1 for the first sample year, and between 53.326 and 47.534g(AFDW)m·-2a·-1 for the second year, which was signifcantly higher than the first year. For Emeritabrasiliensis, high rates of tumover were observed in the two years of study, varying between 9.35 and 7.43a· 1 in the first year, and 6.80 and 6.05a· 1 in the second year. The production in spring was signifcantly higher than in winter. The lif span of Exciloranabr aziliensis was estimated in 20 months in both the first and the second years. The secondar production in winter was signifcantly higher than the ones obtained in spring and summer. We have estimated the production of E br ailiensis in 0.260 and 0.257g(AFDW)m·-2a·-1 for the first year, and in 0.264 and 0.254 g(AFDW)m·-2a·-1 for the second year. No signifcant difference between the productions ofthe two years was fund. The production ofthose two species, added to the production ofPseu dorchestoi deabrasiliensis supplies a total production of 14.556 and 50.999g(AFDW)m·-2a·-1, for the first and second years, respectively. We have fund that the Brachyra, Ocypoe quadrata, Arenaeus cribarius and many species of fsh, such as, Micropogonias furnieri, Menticrrhus americanus, and Paralonchurus brasiliensis had Emeritabrasiliensis as a source offod.