Which environmental factors are most relevant to the distribution of Sicyonia dorsalis (Penaeoidea: Sicyoniidae) in an upwelling region?

Abstract

Knowledge of the environmental factors in an upwelling region is extremely important to understand their relationship with influences in the spatiotemporal densities of penaeid shrimps. Spatial and temporal patterns of distribution of Sicyonia dorsalis were evaluated in relation to temperature, salinity, organic matter, and sediment type in a tropical region influenced by upwelling, using monthly data (2010 to 2011 and 2013 to 2014). The very fine sand was found in 5 m depth and silt and clay and the highest organic matter (mean 16.94%) contents were predominated in 15 m depth. The mean minimum bottom temperature and the maximum salinity were found in spring (18.5 oC and 39.25 psu, respectively). The total of 686 shrimps captured and a consistent pattern of high relative abundance of shrimp in winter and spring and scarcity in autumn was observed. Shrimp abundance was highest in sites at 15 m and positively associated with sediment. The predominance of individuals in finer substrates (silt and clay) was related to higher levels of organic matter content (a food source for shrimp). Temperature was negatively associated with abundance, which was prominent from 19 to 21 °C. Temperature and sediment type were the factors that most influenced the spatiotemporal differences in the density of the S. dorsalis in an area influenced by the upwelling phenomenon. The study highlights the importance of understanding the patterns and drivers to the distribution of shrimps in order to develop modelling species distribution along the coastal region.