Reliable growth estimation from mark–recapture tagging data in elasmobranchs

The somatic growth of individuals governs many aspects a species’ life history and is an important parameter in the assessment populations. Population parameters are typically derived by relating length to their age, with ages commonly estimated from bands formed calcified structures such as vertebrae or dorsal fin spines. However, routinely utilized aging methods may not be reliable for elasmobranchs (sharks, rays skates), motivating alternative approaches. This study evaluates performance seven techniques that estimate von Bertalanffy mark-recapture tagging data. Evaluation was done applying each estimation technique to: 1) simulated error-free data comparing versus known parameters; 2) considering individual variability, measurement error, different length-at-capture distributions, well sample sizes 3) 14 North Atlantic elasmobranch stocks discussing respect biological plausibility conventional length-at-age All investigated returned when without error. When errors introduced simulation, Bayesian implementations Fabens' (BFa) Francis’ (BFr) were found most reliable. For observed only BFa gave biologically plausible results all stocks. Overall, suggest estimating parameters, especially data-limited situations which occur elasmobranchs. prior information needed limited expert knowledge on maximum population stock question. A user guide provided facilitate application method.