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Environmental hypercapnia (high dissolved [CO 2 ]) results from high-density sturgeon culture in systems using O 2 injection and water re-use. The influence of environmental hypercapnia on the growth of the juvenile white sturgeon, Acipenser transmontanus , (fish initial wet weight, about 4 g) was examined by exposing the fish to different CO 2 concentrations in replicate, flow-through aquaria under normoxic conditions (oxygen tension, above 130 torr P O 2 ) at 19 °C. The fish were fed ad libitum rations of commercial trout pellets (Silvercup). After 28 days exposure to severe hypercapnia ([CO 2 ], 45–75 mg 1 −1 ; pH 7.0), growth was significantly reduced ( P 2 ], 0.52 mg 1 −1 ; pH 8.0; SGR, 2.86), presumably due to decreased food consumption. In two subsequent experiments (initial wet weights, approximately 1 and 3 g), a low water pH (a mean of 7.1, via HCl addition to water) did not significantly affect the growth. |
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