Persian Gulf as "The Northwestern limit of Gulf of Oman". This limit is defined as "A line joining Ràs Limah (25°57'N) on the coast of Arabia and Ràs al Kuh (25°48'N) on the coast of Iran (Persia)". The gulf is connected to Indian Ocean through Strait of Hormuz. Writing the water balance budget for the Persian Gulf, the inputs are river discharges from Iran and Iraq (estimated to be 2000 cubic meters per second), as well as precipitation over the sea which is around 180mm/year in Qeshm Island. The evaporation of the sea is high, so that after considering river discharge and
Persian Gulf the second most common source of pollution. Along the mediterranean regions of the Arabian Sea, including the Persian Gulf, the Red Sea, the Gulf of Kutch, the Gulf of Suez, the Gulf of Aqaba, the Gulf of Aden, and the Gulf of Oman, dolphins and finless porpoises are the most common marine mammals in the waters, while larger whales and orcas are rarer today. Historically, whales had been abundant in the gulf before commercial hunts wiped them out. Whales were reduced even further by illegal mass hunts by the Soviet Union and Japan in the 1960s and 1970s. Along with