Given:

In DEB book Chap 3, {95}, we will see that the (volumetric) structural length of an isomorph at constant food density X develops during the juvenile and adult stage as

$$V^{1/3}(t) = f V_m^{1/3} - (f V_m^{1/3} - V_b^{1/3}) \exp \{ - t \dot{r}_B \}$$

where the von Bertalanffy growth rate $\dot{r}_B$ is given by $\dot{r}_B = (3/\dot{k}_M + 3 f V_m^{1/3}/\dot{v})^{-1}$, and the maximum length V_m^1/3 by $V_m^{1/3} = \frac{\dot{v}} {g \dot{k}_M}$, and scaled functional response f is given by $f = \frac{X} {X + K}$, where X is the food density and K the saturation coefficient. Time t and food density X are variables (although Xis kept constant), and saturation coefficient K, energy conductance $\dot{v}$, maintenance rate coefficient $\dot{k}_M$, investment ratio g, (volumetric) length at birth V_b^1/3 are parameters.