Modeling Growth–Time and Weight–Length Relationships in a Single Year-Class Fishery with Examples for North Carolina Pink and Brown Shrimp

Abstract

This paper presents an extension of the classical concepts of growth over time and of a weight–length relationship for a single year-class fishery that explicitly accounts for the stochastic variation known to exist in such a population. It also shows how the extended conceptualization enables one to look at alternative characterizations of a fish population that can be useful when deciding whether or not to allow fishing. Techniques for estimating the extended models efficiently are described, as are procedures for testing for differences in growth and weight–length parameters based on sex and subspecies. The potential use of these models to facilitate the quantification of population biomass is also presented. Data on North Carolina pink and brown shrimp (Penaeus duorarum and P. aztecus) are used to illustrate the concepts and models. Algorithms for effecting several of the proposed procedures are included.Key words: growth, weight, length, biomass, Penaeus duorarum, P. aztecus, von Bertalanffy curve