Ecological situation of Iranian waters in fishing grounds of the Persian Gulf and Oman Sea

The objects of this study were to investigate the status of physicochemical parameters and nutrients in benthic fish hunting grounds the Oman Sea and the Persian Gulf and, from the geographical coordinates of E ۶۱°۲۹ʹN۲۴° ۴۹ʹ and in the waters of Sistan and Baluchestan province to E ۴۹°۴۸ʹN۲۹°۳۸ʹ in the waters of Khuzestan province, during autumn and winter of ۲۰۱۷ to ۲۰۲۰. The average of water temperature, chlorophyll-a, salinity, pH and conductivity in Oman Sea were ۲۴.۹۵ °C, ۱.۰۶ mg.m-۳, ۳۶.۴۵ g/L, ۷.۹۳ and ۵۴.۹۹ mS/cm, respectively. The average of water temperature, chlorophyll-a, salinity, pH and conductivity in the Persian Gulf were ۲۱.۵۳°C, ۰.۸۴ mg.m-۳, ۳۹.۵۳ g/L, ۸.۲۸ and ۵۵.۰۸ mS/cm, respectively. The average of concentrations of nitrate, nitrite, ammonia, phosphate and silicate in the Oman Sea were ۰.۰۴۱, ۰.۰۰۷, ۰.۰۰۶, ۰.۰۱۵ and ۰.۶۳۰ mg/L, respectively. The average of concentrations of nitrate, nitrite, ammonia, phosphate and silicate in the Persian Gulf were ۰.۰۳۴, ۰.۰۰۷, ۰.۰۰۳, ۰.۰۰۸ and ۰.۵۱۷ mg/L, respectively.The analysis of variance of temperature, salinity, chlorophyll-a, nitrate, phosphate and silicate data in the Oman Sea and the Persian Gulf show no significant difference in temperature and salinity in the surface layer of water in Oman Sea and Persian Gulf (p-values<۰.۰۵). The difference between the concentrations of chlorophyll-a, nitrate, phosphate and silicate in the Oman Sea with the concentration of these parameters in the Persian Gulf were significant (P-values>۰.۰۵). Based on the results of this study, the trend of spatial variation of the studied parameters showed that the amount of chlorophyll in the Oman Sea and the Persian Gulf have a relationship with temperature, salinity and silicate. With increasing the water temperature and concentration of silicate, and decreasing the salinity, the amount of chlorophyll-a in these two ecosystems increases. Changes in the concentration of nitrate and phosphate in the study area had no significant effect on the concentration of chlorophyll-a. The water (chlorophyll-a) richness in the Oman Sea was higher than that in the Persian Gulf. The trend of temporal variation of the studied parameters during this study showed that the average of water temperature, salinity, pH, conductivity, the concentration of nitrate, ammonia, phosphate and silicate in the Oman Sea increased, but the concentration of chlorophyll-a and nitrite decreased. The average of salinity, the concentration of ammonia, phosphate and silicate increased in the Persian Gulf, but the average of water temperature, chlorophyll-a, pH, conductivity, the concentration of nitrate and nitrite decreased.

Keywords:

Ecological situation , Fishing ground , Oman Sea , Persian Gulf