Excess dissolved gases including gas bubble disease.

Abstract Gas supersaturation is produced by physical, chemical and biological processes. In hydroelectric systems, gas supersaturation can be produced by air entrainment in spillways or air vented into turbines. In aquaculture systems, gas supersaturation commonly results from air entrainment on the suction side of pumps or heating of water in closed systems. Gas supersaturation can result in the development of gas bubble disease (GBD) or gas bubble trauma in fish. In this chapter diagnosis, control and prevention of the disorders relevant to fresh water and ocean acidification which incluldes hypercapnia, hyperoxia, GBD as well as metal toxicity were discussed.