Selecting the best growth model for elasmobranches
- Published
- Accepted
- Subject Areas
- Aquaculture, Fisheries and Fish Science
- Keywords
- von Bertalanffy growth model, Robertson growth model, Gompertz growth model, sharks, skates and rays
- Copyright
- © 2015 Liu et al.
- Licence
- This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ PrePrints) and either DOI or URL of the article must be cited.
- Cite this article
- 2015. Selecting the best growth model for elasmobranches. PeerJ PrePrints 3:e1550v1 https://doi.org/10.7287/peerj.preprints.1550v1
Abstract
Age and growth information is essential for accurate stock assessment of fish, and growth model selection may influence the result of stock assessment. Previous descriptions of the age and growth of elasmobranches relied mainly on the von Bertalanffy growth model (VBGM). However, it has been noted that sharks, skates and rays exhibit significant variety in size, shape, and life-history traits. Given this variation, the VBGM may not necessarily provide the best fit for all elasmobranches. This study attempts to improve the accuracy of age estimates by testing four growth models—the VBGM, two-parameter VBGM, Robertson (Logistic) and Gompertz models—to fit observed and simulated length-at-age data for 37 species of elasmobranches. The best growth model was selected based on corrected Akaike’s Information Criterion (AICc), the AICc difference, and the AICc weight. The VBGM and two-parameter VBGM provide the best fit for species with slow growth and extended longevity (L∞ > 100 cm TL, 0.05 < k < 0.15 yr-1), such as pelagic sharks. For fast-growing small sharks (L∞ < 100 cm TL, kr or kg > 0.2 yr-1) in deep waters and for small-sized demersal skates/rays, the Robertson and the Gompertz models provide the best fit. The best growth models for small sharks in shallow waters are the two-parameter VBGM and the Robertson model, while all the species best fit by the Gompertz model are skates and rays.
Author Comment
This study attempts to improve the accuracy of age estimates by using four growth functions - VBGF, two-parameter VBGF, Robertson (Logistic) and Gompertz functions - to fit observed and simulated length-at-age data for 43 stocks (including 38 species) of elasmobranchs. The best growth function was then selected based on Akaike’s Information Criterion (AIC), and Akaike weight. The VBGF and two-parameter VBGF provide the best fit for species with slow growth and extended longevity such as pelagic sharks. For fast growing small sharks in deep waters, and for small-size demersal skates/rays, the Robertson and the Gompertz functions provide the best fit. The best growth functions for small sharks in shallow waters are the two-parameter VBGF and Robertson function. The species best fit by the Gompertz model are all skates and rays. This MS has been submitted to PeerJ for peer review.