Long-term patterns of spatial and temporal distribution in the seabob shrimp Xiphopenaeus kroyeri (Decapoda: Penaeidae) population in southeastern Brazil

Abstract

The effect of some environmental factors on the distribution and abundance of different demographic categories of Xiphopenaeus kroyeri (Heller, 1862) was tested for three 12-month periods over 13 years in Ubatuba Bay, Sao Paulo State, southeastern Brazil. Four sites with different characteristics were sampled monthly from January to December 1998, July 2006 to June 2007 and September 2010 to August 2011. Bottom water temperature and salinity samples were taken monthly, and one sediment sample from each site was taken during each period. Although total abundance, as the number of adult males and non-reproductive females did not differ among periods, in 1998 the abundance of juveniles was greater and reproductive females was lower than the other two periods. The high abundance of juveniles in 1998 was associated with the high frequency of optimal temperatures for juvenile’s metabolism and this environmental variable can influence the abundance of individuals among years. Adult shrimp can be established in sites with variations in sediment grain size composition, whereas juveniles are more abundant in sites with finer sand. We suggest that areas with high juvenile abundance in Ubatuba Bay must have controlled exploitation and that the fishery can be focused on the deepest areas, where adults are predominant.