Mainguy, Julien and Moral, Rafael de Andrade (2021) An Improved Method for the Estimation and Comparison of Mortality Rates in Fish from Catch‐Curve Data. North American Journal of Fisheries Management, 41 (5). pp. 1436-1453. ISSN 0275-5947

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Abstract

Catch-curve analyses are routinely used to estimate instantaneous mortality (Z) in fish, and as the age-frequency data are often over dispersed, the application of a variance bias-correction factor has been recommended. The extensions of the Poisson generalized linear model (GLMPoisson) may, however, constitute a better alternative, as they model the variance (SE) in counts more adequately with their specific dispersion parameter for more accurate estimations and statistical comparisons. To test this idea, simulated age-frequency data generated under four dispersion scenarios were analyzed according to six currently available methods and compared with the results of a GLMPoisson and five of its extensions to evaluate each method-specific bias in Z SE estimates. Empirical age-frequency data from sampled Walleye Sander vitreus and Arctic Char Salvelinus alpinus populations in Quebec, Canada, were then used ´ to illustrate the applicability of our GLM-based method, which relies on the behavior of Pearson residuals to assess model adequacy and an information-theoretic approach for model selection. All analyses revealed that Z-estimates were generally accurate among the methods considered, except under the most likely situation of quadratic over dispersion met in ecological studies, for which only the negative binomial type 2 and the mean-parametrized Conway– Maxwell–Poisson (CMP) extensions were adequate to estimate both Z and its SE. Linearly over dispersed data were best modeled by the negative binomial type 1 and generalized Poisson (GLMGP) extensions; the GLMCMP and GLMGP were the most appropriate to model under dispersed data, whereas the GLM Poisson adequately modeled equi- dispersed data, similar to the Chapman and Robson (1960) method. Statistical comparisons of Z SE for grouping factors, such as year or site, were correctly achieved when the most adequate and statistically supported GLM Poisson extension was applied. Altogether, the proposed GLM-based method should help to circumvent the identified issues related to SE estimation for statistical inferences about mortality rates for fisheries management decision making.

Item Type:	Article
Additional Information:	Cite as: Mainguy, J. and Moral, R.D.A., 2021. An Improved Method for the Estimation and Comparison of Mortality Rates in Fish from Catch‐Curve Data. North American Journal of Fisheries Management, 41(5), pp.1436-1453.
Keywords:	Comparative analysis; Confidence interval; Datasets;
Academic Unit:	Faculty of Science and Engineering > Mathematics and Statistics Faculty of Science and Engineering > Research Institutes > Hamilton Institute
Item ID:	17905
Identification Number:	https://doi.org/10.1002/nafm.10665
Depositing User:	Rafael de Andrade Moral
Date Deposited:	30 Nov 2023 14:19
Journal or Publication Title:	North American Journal of Fisheries Management
Publisher:	Research Gate
Refereed:	Yes
URI:	Publisher
Use Licence:	This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available here

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