Individual physiological responses were converted into energy equivalents and used in the balanced energy equation:
C = P + R + U + F
where: C = total consumption of food energy; P = Production of both somatic and reproductive tissue R = energy expenditure in respiration U = energy loss in excretion F = energy loss in feaces and pseudofeaces
The absorbed energy, A, is the product of consumption, C, and the absorption efficiency of energy from the food. Production may be expressed as:
P = A - (R + U)
Production can be referred as "Scope for growth" or the energy that the animal can use for growing.
Calculation of C, A, R and U (J/g h) is as follows:
C = CR (L/g h) * POM (mg/L) * 23 J/mg ash-free dry weight; A = C * AE R = VO2 (mlO2 / g h) * 20.33 J/ml O2 U = mg NH4/ g h * 19.4 J/ mg NH4
CR is the volume of water cleared of particles per gram mussel per hour and was calculated according to the expression: