Whether exploratory or commercially, acoustic fishery benefits are important in finding a school of fish and other aquatics, but using this procedure and state accurate detailed information for the whole specifications of organisms require sufficient information of sound speed changes, course of ray propagation and their rate of  absorption and attenuation . This research has considered the quality of sound speed changes towards the depth in terms of physical specifications of Dayer port' s water situated in the northeast of Farsi island and around ۵۰ Kmsouth of Delvar (latitude ۲۸˚,۲' north and longitude ۵۰˚,۵۸΄ east), and also has calculated the amount of absorption in these regions. The results have shown that sound speed is constant with depth and temperature decreases within the first۱۱ meters, but after that it declines. In the ۱۹- meter depth, there is a stronger decrease which is related to the decrease of temperature. It is because of colder current in this region. By investigating sound absorption curves of the area, it is observed that the maximum amount of attenuation is within the depth of ۱۷ to ۲۷m

sound, Environmental factors, Dayer port, Persian Gulf, Iran