The model describes an aquaculture system with a tank of water in which fish respire and grow. The oxygen content in the tank is described by this model as well as the development in the mass of fish with time.
This consumption of oxygen varies with the oxygen level in the tank and is affected by the kinetics of the respiration proces as described by the Michaelis-Menten equation:
The respiration rate (v) is, as shown in the model, thereby affected by the half-saturation constant (which was determined by the model https://insightmaker.com/insight/47491/Determination-of-Km-value-aquaculture-W2), the maximum respiration rate, determined as the product of the temperature dependent weight-specific respiration rate and the weight of fish and finally the oxygen concentration in the tank.
A flow of water into and out of the tank can be introduced by changing the flow rate from 0.
In the determination of the growth rate of the fish it is assumed that the fish incorporate one mole of carbon for each mole of oxygen respired and that each mole of oxygen respired gives 26,4 g wet biomass.
With no flowing water into and out of the system, a Km-value of 134, a temperature of 15 degrees Celcius, an initial concentration of oxygen in the tank of 500 umol/L and 10 kg of fish in the tank, which contains 1000 L of water, the oxygen gets depleted within the first 20 hours. I think there is a problem with the fish growth in the model since the weight of fish does not change..?
A flow of 50 L/h can be introduced, and this adjustment will lead to a slightly decreasing oxygen level over a simulation period of 4380 h. Yet the fish do not seem to grow.