Estudo da distibuição, abundância e diversidade de camarões penaeideos juvenis no estuário do Rio Incomati

Abstract

The present study was carried out from February to June 2003 in Muntanhana, and aimed to study the distribution, abundance and diversity of juvenile Penaeidae in the Incomati River estuary. Two habitats were defined for sampling, namely along the channel and inside the mangrove swamp. The channel was subdivided into three stations, from the mouth towards the upstream (Station by the Bay, Intermediate Station and Station upstream), at the base three different salinity gradients. The mangrove was divided into two areas, taking into account its degradation status. Samples were taken fortnightly, on four consecutive days, during daytime and nighttime high tides. Sampling in the channel was done with the help of a 2 x 0.5 m beam trawl towed by a 5 m long boat assisted by a 25HP outboard motor. In the mangrove fixed nets of 1mm mesh opening were used for sampling. The results obtained in this work indicate that, in the channel, with the exception of salinity, other factors such as temperature and depth did not differ significantly. Regarding mangai, the three factors (salinity, temperature and depth) did not show significant variations between degraded and non-degraded mangai. A total of 6649 Penaeid shrimp belonging to 6 species (Penaeus indicus, Penaeus monodon, Penaeus japonicus, Penaeus semisulcatus, Metapenaeus monoceros and Metapenaeus stebbingi), were collected in the channel, with Metapenaeus monoceros being the most abundant species (39. 93%) while 184 shrimps belonging to 4 species, namely P.indicus, M.monoceros, M.stebbingi and P.japonicus, were caught in the mangrove channel with Penaeus indicus being the most abundant species (72.28%). In general, night catches were higher than day catches. The station near the Bay and the non-degraded mangrove swamp showed higher densities and average biomasses. (TRADUÇAO NOSSA)