<P> One of the more unusual marine mammals living in the Persian Gulf is the dugong ( Dugong dugon ) . Also called `` sea cows '' , for their grazing habits and mild manner resembling livestock , dugongs have a life expectancy similar to that of humans and they can grow up to 3 metres ( 9.8 feet ) in length . These gentle mammals feed on sea grass and are closer relatives of certain land mammals than are dolphins and whales . Their simple grass diet is negatively affected by new developments along the Persian Gulf coastline , particularly the construction of artificial islands by Arab states and pollution from oil spills caused during the `` Persian Gulf war '' and various other natural and artificial causes . Uncontrolled hunting has also had a negative impact on the survival of dugongs . After Australian waters , which are estimated to contain some 80,000 dugong inhabitants , the waters off Qatar , Bahrain , UAE , and Saudi Arabia make the Persian Gulf the second most important habitat for the species , hosting some 7,500 remaining dugongs . However , the current number of dugongs is dwindling and it is not clear how many are currently alive or what their reproductive trend is . Unfortunately , ambitious and uncalculated construction schemes , political unrest , ever - present international conflict , the most lucrative world supply of oil , and the lack of cooperation between Arab states and Iran , have had a negative impact on the survival of many marine species , including dugongs . </P>
what has happened to the coastline of the persian gulf over time
construction of artificial islands by Arab states pollution from oil spills caused during the `` Persian Gulf war ''