This parameter is the theoretical age of the fish at zero size under the assumption that the von Bertalanffy growth curve describes the growth accurately right down to zero length.The definition changes according to candidate growth models, e.g., the Logistic, Johnson, and Gompertz models correspond to the inflection point for each curve; for generalized von Bertalanffy growth model, t₀ has similar interpretation as in the von Bertalanffy assuming the equation to be valid at all ages; a similar assumption is applied to the Richards growth model (Katsanevakis, 2006). The t₀ parameter is largely artificial, in so far as it defines the age at which the organism would be of zero length if it grew throughout its life with the same pattern of growth as in the early stages.