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 The aim of this study was to compare the accumulation of heavy metals copper, zinc and cadmium and to investigate the changes of metallothionein as a biomarker of contamination in the gill tissue of the ghost crab Ocypode saratan in the two time periods before Monsoon (May) and after Monsoon (November) in mongrove forests. Chabahar and Gwater Bay was done in 2019. The results of the study showed that in both pre-Monsoon and post-Monsoon seasons the pattern of metal accumulation in the gill tissue of the ghost crab is zinc, copper, cadmium.The mean concentrations of copper, zinc and cadmium were obtained in the pre-monsoon and post-monsoon seasons at Chabahar station, 173.6 ± 3.83, 186.43 ± 3.1, 0.095 ± 0.008, respectively and 156.7±4.15 ،175.13 ± 2.8, 0.026 ±0.003 and in Gwater station the average concentrations of copper, zinc, cadmium in the two pre-Monsoon and post-Monsoon seasons were respectively 237.03 ± 6.4, 231.8 ± 1.8, 0.048 ± 0.003 and 205.9 ± 6.34, 253.2 ±  2.13, 0.037 ± 0.015 μg/g dry weight. The mean levels of metallothionein in pre-monsoon and post-monsoon season in Chabahar station were 2.02 ± 0.01 and 0.1 ± 0.06, respectively, and in goiter station were 2 ± 0.02 and 0.12 ± 0.02, respectively. Comparison of metallothionein levels between Chabahar and Gwater stations was not significant (P<0.05). But in both stations separately between the two pre-Monsoon and post-Monsoon seasons, there was a significant difference (P<0.05). Correlation between metallothionein and metals showed that there was no correlation between metallothionein and the studied metals. Therefore, according to the observations, changes in the concentration of metallothionein in this species are not affected by heavy metals and can be due to changes in the environmental conditions of the seasons.

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This research was conducted with the aim of determining the biodiversity of Pertaran communities in three areas with mangrove cover and in 9 stations including one station in Gowatr Bay and 4 stations in each of Gowatr bay and Bahu Kalat on the eastern coast of Chabahar port. From each station, from the winter of 2019 to the fall of 2014, three sediment samples were collected seasonally for the separation and identification of sediments and one sample for the analysis of grain size and total organic matter of the sediments by Grab van Veen with a cross-sectional area of 0.028 square meters. In total, 12 genera belonging to 10 families were identified. Among the groups of the detected families of spionidae, the highest percentage of the average frequency with 13.70% was related to the Spionidae family. The survey of the density of the birds in total is 17800 ± 180 in the mentioned seasons, the average density of the birds in winter is 8720 ± 42 and the average density of the birds in the autumn is 9080 ± 181.63 in the mentioned seasons, the lowest average in winter is related to the Nereidae family: 0.5 600±67 and the most number was for Spionidae family: 1280±31.47 individuals in one square meter. The lowest average in autumn was related to the Nereidae family: 560 ± 32.65 and the highest to the Spionidae family: 1160 ± 62.94 individuals per square meter.