The salinity of the oceans depends on factors like rate of evaporation and supply of fresh water.
In Oceans where rate of evaporation is more than the supply of fresh water, the salinity is higher.
In Oceans where supply of freshwater exceeds the rate of evaporation, salinity is low.
Salinity is not affected much in areas where supply of freshwater and the evaporation of water is low.
Thus, oceans located on the same latitude do not have the same salinity.
