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Many biological processes are temperature dependent and could be adversely affected by even a few degrees of temperature change (Harley, 2006). Higher temperature waters, such as those in the tropics have less primary production in the form of phytoplankton, which almost all fish derive their energy from. A drop in the amount of primary production causes a drop in the higher trophic levels as well. Therefore, it is reasonable to predict in many cases this will cause the populations of stocks to decrease Addition of fresh water from melting ice caps decreases surface salinities in ocean regions, which can be detrimental to species with low tolerances to changes in salinity (Harley, 2006).
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