Spatiotemporal evaluation of Xiphopenaeus kroyeri (Heller, 1862) abundance in a region of the Southwest Atlantic shelf

Abstract

Several activities, such as port and fishing operations, exploit coastal marine ecosystems around the world, creating significant environmental impact. Since these activities often overlap spatially, they can interfere with each other. This paper aims to evaluate the spatiotemporal variability in the relative abundance of the Atlantic seabob shrimp (Xiphopenaeus kroyeri), caught in the central coastal marine region of the State of São Paulo, Brazil, where port activity takes place next to environmental protection areas. Commercial fishing data from a 6-year period (2009–2014) were used to perform this evaluation. Generalized linear models (GLMs) were applied to the catch and effort data, and model coefficients were used to calculate the catch per unit effort (CPUE, kg/fishing day), which was standardized per square nautical mile and year. Semivariogram and kriging techniques were used to evaluate the existence of spatial dependence in the data and to estimate the standardized CPUE in unsampled areas. Isotropic spherical semivariogram models were fitted using the least squares method, and they showed a pattern of spatial dependence for all years. Variation in Atlantic seabob relative abundance within the vessel demarcation area of the Port of Santos was similar to that in the area used for dumping dredged material, although the latter was fished more frequently, thus creating larger catches. Therefore, commercial fishing data can be used to evaluate the spatiotemporal variation in the relative abundance of marine species in coastal regions. The results suggest that fishing and port activities interfere with one another in the region of the Port of Santos.