An aquaculture safety board suggests that to prevent respiratory acidosis in farmed Atlantic salmon, blood pH should not drop below $7.2$.

The board currently recommends that salmon should not be exposed to:

• water with $>15.0{mg\; dm}^{-3}$ of dissolved ${CO}_2$ for more than $12$ hours.
• water with $>40.0{mg\; dm}^{-3}$ of dissolved ${CO}_2$ for more than $2$ hours.

Scientists used a physiological computer model to calculate the dissolved ${CO}_2$ exposure concentrations that would lead to a blood pH of exactly $7.2$ in juvenile and adult salmon.

The table below shows the results of their model:

Table: Dissolved ${CO}_2$ concentration in water / ${mg\; dm}^{-3}$ resulting in a blood pH of $7.2$

The scientists concluded that the safety board's exposure limits for dissolved carbon dioxide should be reduced to protect salmon populations from acidosis.