Marking, L. L., 1987, Evaluation of gas supersaturation treatment equipment at
fish hatcheries in Michigan and Wisconsin: The Progressive Fish Culturist, v. 49,
no. 3, p. 208-212.

Abstract: 

Fish hatcheries operated in Michigan and Wisconsin by the U.S. Fish and Wildlife
Service and in Michigan  by the Michigan Department of Natural Resources have
reported severe mortalities of lake trout (Salvelinus  namaycush ) in recent years,
largely from gas bubble disease caused by gas supersaturation. Until 1985, the 
systems most commonly used to alleviate this condition were packed column
aeration units and vacuum  degassers. Sensitive species require water that is both
free of gas supersaturation and has high dissolved oxygen.  Packed column
aeration decreases supersaturation to about 104% and simultaneously increases
dissolved  oxygen in the treated water. Vacuum degassers can decrease
supersaturation to less than 100%, but the negative  pressure applied in this
process also reduces the dissolved oxygen. Oxygen injection systems effectively
decrease  nitrogen and total gas pressure to less than 100% and increase oxygen to
saturation or even higher desired  concentrations.

Keywords:

fish-culture, water-treatment, degassing, supersaturation, hatcheries, USA,
Salvelinus-namaycush, oxygenation