en fish disease fish disease پژوهشي Orginal research papers Concentrations of lead, copper, cadmium, and mercury were determined in sediments and two selected marine organisms (<em>Cynoglossus arel</em> and <em>Panulirus</em> <em>homarus</em>) collected from Jask Port, Darak Port, Pozm Port, Gulf of Chabahar and Gowatr Port in the north coasts of the Oman Sea during pre (spring) and post (autumn) monsoon in 2017. Heavy metals concentrations were determined by atomic absorption spectrophotometry. Results showed that there are statistically significant differences between studies concentrations in sediments during pre and post-monsoon at sample locations (<em>p</em><0.05). Analysis of variance revealed a significant difference in the muscle of <em>C. arel</em> and <em>P.</em> <em>homarus</em> in pre and post-monsoon between the different sites (<em>p</em><0.05), except for copper in the muscle of <em>P.</em> <em>homarus </em>in the post-monsoon (<em>p</em>>0.05). In sediments and muscle of <em>C. arel</em> and <em>P.</em> <em>homarus</em> the trend in the mean metal concentrations was: Cu> Pb> Cd> Hg; Cu> Pb> Cd> Hg and Cu> Hg=Pb> Cd, respectively. Also, the trend in the mean metal concentrations in the samples was sediment ><em> P.</em> <em>homarus></em> <em>C. arel.</em> However, paired t-test analysis for comparing heavy metal concentration in pre and post-monsoon showed only a significant difference for cadmium in the muscle of <em>P. homarus </em>(<em>p</em><0.01). Totally, by comparing the results obtained from this study indicated that the accumulation of lead, copper, cadmium, and mercury in sediments and muscle <em>C. arel</em> and <em>P.</em> <em>homarus</em> at the Gulf of Chabahar and Jask Port is higher than other regions of the Iranian coasts along the Oman Sea which studied in current research. Oman Sea, Heavy metals, Sediment, Cynoglossus arel, Panulirus homarus 1638 1656 http://jifro.ir/browse.php?a_code=A-10-2966-1&slc_lang=en&sid=1 A. Mahdi Abkenari armansazan.elmopazhohesh@gmail.com 100319475328460037998 100319475328460037998 Yes Department of Fisheries, Chabahar Branch,Islamic Azad University,Chabahar, Iran M. Yahyavi mehrdad.kamran@yahoo.com 100319475328460037999 100319475328460037999 No Department of Fisheries, Bandar Abbas Branch, Islamic Azad University, Bandar Abbas, Iran A. Bahri kamimehrdad@yahoo.com 100319475328460038000 100319475328460038000 No Department of Fisheries, Bandar Abbas Branch, Islamic Azad University, Bandar Abbas, Iran H. Jafaryan amiir.raisi@yahoo.com 100319475328460038001 100319475328460038001 No Department of Fisheries and Forestry, Faculty of Natural Resources, Gonbad Kavous University, Golestan, Iran.