Asymptotic growth, egg production and trivariate allometry in Esox masquinongy Mitchill

Multivariate growth models based on the Lotka-Volterra equations seem more complicated than necessary for a fruitful analysis of relative growth data. A simpler and more practical approach combines multivariate allometry with parabolic or asymptotic growth with respect to time. A modified von Bertalanffy curve, X = A [1-exp (-t/D)]C, is compatible with allometry and yields a satisfactory description of somatic growth and egg production in the female muskellunge (Esox masquinongy). A multiplicative variation model appears adequate and partial linearization can be used. While the muskellunge reaches a large size, the present analysis suggests that its growth pattern is limited (asymptotic, determinate). The allometry exponents inferred from the multivariate asymptotic growth model differ slightly from those obtained from principal component analysis or from a trivariate linear structural relationship, but the latter may reflect physiological age rather than physical time.