Interpretation of tagging data to study growth of the Atlantic sailfish (Istiophorus platypterus)

Despite the necessity of understanding growth in population dynamics studies and the need for accurate growth parameters to define fishery management bench marks, these are almost absent for the Atlantic sailfish [Istiophorus platypterus (Shaw in Shaw and Nodder, 1792)]. A tagging database that contains more than 1200 returns exists, but has been considered unusable for estimating age primarily because of errors in the estimated size at release and the lack of information on sex. Here, we present an analysis of these errors and provide an algorithm that permits robust growth parameter estimation for Atlantic sailfish. The algorithm yields L _∞ values of 221.0 and 160.8 cm and K values of 0.617 and 0.583 yr⁻¹ for females and males, respectively. The algorithm can be applied to other billfish species which have adequate tagging data.