Variation in growth for Hecate Strait English sole (Parophrys vetulus) with implications for stock assessment

In this study we analysed length-at-age data to characterise the growth of English sole (Parophrys vetulus) and to examine the implications of incorpo rating uncertainty about growth into English sole stock assessment. Unlike previous analyses of English sole that employed Von Bertalanffy growth. we used a flexible parameterisation of growth after Schnute (1981) that better accommodated observed patterns in the length-at-age data. The model parame ters always exist, even when the most appropriate growth form does not incl ude a maximum size asymptote. and they have statistically stable properties . Also, the model parameters are expressed as quantities that have direct b iological interpretation. Based on examination of annual growth parameter e stimates, we concluded that a change in ageing methodology, sample bias and low sample size precluded analysis of the response of growth to environmen t and density-dependent effects. We also discuss the implications of uncert ainty in the growth parameters on a yield per recruit analysis. (C) 2000 El sevier Science B.V. All rights reserved.