Secondary production of Acartia tonsa Dana, 1849 and A. lilljeborgii Giesbrecht, 1889 in an Amazonian estuary (Brazil)

Abstract

The dynamics of the copepods A. tonsa and A. lilljeborgii were described for the first time in the Taperaçu Estuary. The acartiids were collected using plankton nets (200 μm) in June 2012, March 2013 (rainy season) and September 2012 and 2013 (dry season). The oscillations in rainfall and the fluctuations in hydrological variables influenced the abundance, biomass, and production of both A. tonsa (17 ± 23 to 8501 ± 13,248 ind.m−3; 16,385.29 mg.C.m−3; 0.09 ± 0.21 to 355.17 ± 590.84 mg.C.m−3.d−1) and A. lilljeborgii (14 ± 11 to 1470 ± 1591 ind.m−3; 22,398.40 mg.C.m−3; 177.99 ± 263.13 mg.C.m−3.d−1) with clear monthly, seasonal, and spatial patterns. The high levels of production observed may be related to the presence of waters rich in particulate organic material derived from the adjacent mangrove forests. This material is consumed by a number of copepod species, in particular A. tonsa and A. lilljeborgii, favoring the development and reproduction of both species which are characterized by high rates of productivity in the study estuary. The present results indicate that the biomass and productivity in equatorial mangrove estuaries may be relatively high in comparison with the levels observed in other coastal systems around the world and that earlier stages of both species have a great relevance for biomass and production in Amazonian estuaries.