The von Bertalanffy model for incremental data

von Bertalanffy derived this equation in 1938 from simple physiological arguments. It is the most widely used growth curve and is especially important in fisheries studies. There are a number of different ways that this equation can be written (see von Bertalanffy growth equation). When using incremental data the version used is

where t is time,

l is length (or some other measure of size),

K is the growth rate

b a parameter determining the rate of growth at t = 0 and

L∞, termed 'L infinity' in fisheries science, is the asymptotic length at which growth is zero.

In this version of the equation the parameter t0 is not included. However b = exp(kt0) so t0 can be easily calculated.