Modeling time-varying growth using a generalized von Bertalanffy model with application to bloater (Coregonus hoyi) growth dynamics in Lake Michigan

Canadian Journal of Fisheries and Aquatic Sciences
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Abstract

A concurrent increase in lakewide abundance and decrease in size-at-age of bloater (Coregonus hoyi) in Lake Michigan have suggested density-dependent growth regulation. We investigated these temporal patterns by fitting a dynamic von Bertalanffy model and length–weight relationship with time-varying parameters to mean length- and weight-at-ages (ages 1–7) from annual surveys (1965-–1999). We modeled yearling length, asymptotic size (L‰), and the parameters of a power relationship between mean weight and mean length (α and β) as changing slowly over time using a random walk model. The Brody growth coefficient (k) was modeled as a linear function of L‰ with year-specific random deviations. Our results support a positive relationship between L‰ and k, indicating that under conditions supporting larger asymptotic lengths, individuals approach the asymptote more rapidly. We explored the relationship between year-specific growth parameters and indices of lakewide bloater abundance and found evidence of density-dependent growth. However, in the most recent years, L‰ and yearling length have remained low in Lake Michigan despite low bloater abundances, suggesting the occurrence of a fundamental shift in the food web.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Modeling time-varying growth using a generalized von Bertalanffy model with application to bloater (Coregonus hoyi) growth dynamics in Lake Michigan
Series title Canadian Journal of Fisheries and Aquatic Sciences
DOI 10.1139/f03-003
Volume 60
Issue 1
Year Published 2003
Language English
Publisher NRC Research Press
Publisher location Ottawa, ON
Contributing office(s) Great Lakes Science Center
Description 12 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Canadian Journal of Fisheries and Aquatic Sciences
First page 55
Last page 66
Country United States;Canada