Variação espaço-temporal da ictiofauna de zona de arrebentação em praias do litoral paraibano

Abstract

The spatiotemporal influence on the ichthyofauna of the surf zone was evaluated in two studies: (I) Annual seasonal variation of the density and biomass in two beaches of the coast of Paraiba, and (II) Composition of the ichthyofauna in different lunar phases in the beach of Miramar (Cabedelo), Paraiba. In both studies, several important environmental variables (temperature, salinity, turbidity, conductivity and pH) were measured and correlated with the results of density and biomass. In all two studies, 13,206 (68.5 kg) were caught. In the annual study (132 trawls), the most captured species were in descending order of occurrence frequency Polydactylus virginicus, Stellifer brasiliensis, Anchoa tricolor, Conodon nobilis, Larimus breviceps, Haemulopsis corvinaeformis, Cathorops spixii, Selene vomer, Menticirrhus americanus and Rhinosardinia bahiensis. While in the study with the lunar phases (48 trawls) in Cabedelo were P. virginicus, S. brasiliensis, A. tricolor, L. breviceps, C. nobilis, H. corvinaeformis, S. vomer, Trachinotus falcatus, Trachinotus goodei, Caranx latus, Anchovia clupeoides and Chilomycterus spinosus. In both studies, there was dominance in the surf zone were similar to most species of higher occurrence (P. virginicus, S. brasiliensis, A. tricolor, C. nobilis, L. breviceps, H. corvinaeformis, S. vomer, although C. spixii, M. americanus and R. bahiensis were dominant only in the annual study (Article II), and T. falcatus, T. goodei, C. latus, A. clupeoides and C. spinosus (Article I). In the second study, density (ind.m-2) and biomass (g m-2) of the ichthyofauna of the beach of Miramar and Costinha beach were (0.069; 0.040) and (0.19; 0.09) respectively for these parameters and sites. In the first study (lunar phases) the average density and total biomass were 0.08 ind m-2, and 0.13 g m-2, respectively. Seasonality was decisive among dry months (may, october, november, december in 2014, and february in 2015), when A. tricolor, P. virginicus, Selene vomer, M. americanus, H. corvinaeformis, and C. nobilis were most abundant, whereas for the rainy months (july, August, September, march and may-2015) R. bahiensis And C.spixii were most abundant. For the highest biomass, the species in the rainy months were P. virginicus, M. americanus, and R. bahiensis, while A. tricolor, H. corvinaeformis and S. vomer in the dry months did not show seasonal differences (in density and biomass), however were present throughout the year. In addition, the new moon influenced the abundance of A. tricolor, T. falcatus and L. breviceps in the months of june, although this last species was also present in the new moon. Also, A. clupeoides occurred on waning moon and in the same month. The most important environmental variables in the two studies were salinity and turbidity with significant differences in ANOVA, RDA and CCA analysis. In both beaches (Miramar and Costinha) these surf zone areas can be considered important for the ecology and seasonal distribution of juveniles in Paraíba, with few dominant species, including rare and low occurrence species. In addition to these seasonal variations are also regulated by the lunar phases.