Fitting straight lines to Hiatt growth diagrams: a re-evaluation

Abstract

The growth of crustaceans is often summarized by plotting the size of individuals before moulting against their size after moulting. A new model consisting of a pair of straight lines constrained to meet at some pre-moult size is proposed for fitting the data points on such plots. This model is compared with a hyperbolic model presented by Mauchline (1976) and is shown to fit crustacean growth data significantly better. It is also demonstrated that this model can detect the size of sexual maturity when it is associated with an abrupt change in growth.