An algorithm for the von Bertalanffy seasonal cessation in growth function of Pauly et al. (1992)

• The mathematical foundation of the seasonal cessation in growth model proposed by Pauly et al. (1992) is reviewed.
• An algorithm for implementing the seasonal cessation in growth model proposed by Pauly et al. (1992) in any software capable of performing nonlinear least-squares is proposed.
• Use of the algorithm is demonstrated with four sets of seasonal length-at-age data.

Pauly et al. (1992; Australian Journal of Marine and Freshwater Research 43:1151–1156) introduced a modified von Bertalanffy seasonal growth function that allowed for a period of no growth. Pauly et al. (1992) provided special purpose software to fit the model to length-at-age data, but this software is no longer available and specific details to implement a critical aspect of the new growth function were not clear. I provide details for this critical aspect of the function, implement it in the open-source R environment, and briefly demonstrate the use of this function with four data sets. With this, the growth function of Pauly et al. (1992) is now readily available to all scientists with access to software that can fit nonlinear models to data. Thus, this growth function may be implemented in more situations and its fit rigorously compared to the results from other models of fish growth.