The effect of temperature, salinity, and depth on CPUE of Metapenaeus affinis and Penaeus semisulcatus in the coastal regions of Khuzestan Province using regression and RDA

There is limited information about the relationship between abiotic and biotic variables of the shrimp/prawn stocks in the Persian Gulf. Consequently, the effect of some environmental factors, including temperature, salinity, and depth, on the abundance of two commercial species, Jinga shrimp (Metapenaeus affinis) and green tiger prawn (Penaeus semisulcatus), on the coasts of Khuzestan Province were assessed in the present study. For this purpose, regression, and RDA, as an ordination method, were employed to investigate the impacts of the depth, temperature, and salinity on the capture per unit effort (CPUE). The maximum CPUE for M. affinis in the western region (Life’h- Buseyf) was 18.75kg/h at a depth of 5m, 28.5°C and 40ppt salinity. It was obtained the 2.03kg P. semisulcatus per hour from the eastern region (Bahrkan) at 22m, 32°C, and 40ppt. The results of RDA revealed that the changes in CPUE have a statistical relationship with environmental variables. So that this relationship is direct for Penaeus semisulcatus and inverse for Metapenaeus affinis, and the sea depth was the most significant factor in fishing both shrimp/prawn species. The selection of the leading variables has also confirmed these results. Additionally, the temperature was recognized as the subsequent influencing factor, and the salinity variable had no significant effect on the CPUE of species. Regression models showed only a significant impact of depth on the CPUE of Penaeus semisulcatus, and the capture of Metapenaeus affinis lacked any statistical effectiveness of environmental variables.