Aquatic organisms are exposed to local and global environmental stressors, such as pollutants and acute changes in temperature. Exposure of organisms to stressors may result in a series of biochemical and physiological changes. At the organismal level, these changes are mediated by the neuroendocrine system. In addition to this neuroendocrine stress response, there is a cellular stress response following exposure to stressful situations. These stress responses in organisms affect their general health, disease resistance, growth, and reproduction.