Physiological constraints in shrimp cultures

The biological requirements of animals change considerably during development from the egg to the (early) adult stage. Some basic physiological requirements (respiration, excretion of metabolic end products, space requisites, aspects of feeding biology) of cultured animals are considered in relation to design (surface area, depth) and maintenance (water refreshment) of shrimp (and fish) culture units. From general relations between respiration and food intake with body weight, the required changes in medium dimensions or animal density can be derived. It follows that water volume of a rearing system should be kept approximately proportional to biomass, surface area, food and water supply and should remain proportional to the metabolic weight (W^b) of the biomass. Depth and water refreshment should be proportional to, respectively, W^1−b and W^b−1 (b ∼ 0.74). The increase of body weight requires a reduction of animal density proportional to the reciprocal of metabolic weight. This can be achieved, for instance, by stepwise increasing the available surface area of the culture enclosure by 10^0.735 (∼5.4) times and depth by 10^0.265 (∼1.8) times at each 10-fold increase in biomass.