Estimating age at a specified length from the von Bertalanffy growth function

North American Journal of Fisheries Management
By:  and 

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Abstract

Estimating the time required (i.e., age) for fish in a population to reach a specific length (e.g., legal harvest length) is useful for understanding population dynamics and simulating the potential effects of length-based harvest regulations. The age at which a population reaches a specific mean length is typically estimated by fitting a von Bertalanffy growth function to length-at-age data and then rearranging the best-fit equation to solve for age at the specified length. This process precludes the use of standard frequentist methods to compute confidence intervals and compare estimates of age at the specified length among populations. We provide a parameterization of the von Bertalanffy growth function that has age at a specified length as a parameter. With this parameterization, age at a specified length is directly estimated, and standard methods can be used to construct confidence intervals and make among-group comparisons for this parameter. We demonstrate use of the new parameterization with two data sets.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Estimating age at a specified length from the von Bertalanffy growth function
Series title North American Journal of Fisheries Management
DOI 10.1080/02755947.2017.1342725
Volume 37
Issue 5
Year Published 2017
Language English
Publisher Taylor & Francis
Contributing office(s) Coop Res Unit Leetown
Description 15 p.
First page 1176
Last page 1180