Effects of age-based movement on the estimation of growth assuming random-at-age or random-at-length data

TitleEffects of age-based movement on the estimation of growth assuming random-at-age or random-at-length data
Publication TypeJournal Article
Year of Publication2017
AuthorsLee H.H, Thomas L.R, Piner K.R, Maunder MN
JournalJournal of Fish Biology
Volume90
Pagination222-235
Date Published2017/01
Type of ArticleArticle
ISBN Number0022-1112
Accession NumberWOS:000392427500013
Keywordsage-based growth; Bertalanffy; bias; gear selection; length-based growth; mortality; parameters; selectivity; simulation; Stock assessment; von
Abstract

Simulation methods were used to generate paired data from a simulated population that included the age-based process of movement and the length-based process of gear selection. The age-based process caused bias in the estimates of growth parameters assuming random at length, even when relatively few age classes were affected. Methods that assumed random at age were biased by the subsequent inclusion of the length-based process of gear selection. Additional knowledge of the age structure of the sampled area is needed to ensure an unbiased estimate of the growth parameters when using the length-conditional approach in the presence of age-based movement. Estimates of the variability in the length-at-age relationship were better estimated with the length-conditional than the traditional method even when the assumptions of random at length were violated. Inclusion of paired observations of length and associated age inside the population dynamics model may be the most appropriate way of estimating growth.

DOI10.1111/jfb.13177
Short TitleJ. Fish Biol.
Student Publication: 
No