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Please use this identifier to cite or link to this item: http://hdl.handle.net/1807/19305

Title: Life History, Maternal Quality and the Dynamics of Harvested Fish Stocks
Authors: Venturelli, Paul Anthony
Advisor: Shuter, Brian
Abrams, Peter
Department: Ecology and Evolutionary Biology
Keywords: walleye
Sander vitreus
maternal influences
maternal effects
recruitment
density-dependence
temperature
growing degree day
age
lifespan
maturity
sustainable
cod
Gadus morhua
egg
Ricker
reproductive rate
demographics
stock-recruitment
fecundity
mortality
growth
life history
Issue Date: 3-Mar-2010
Abstract: Knowledge of offspring production (recruitment) is fundamental to understanding and forecasting the dynamics of a population. In this thesis, I focus on two demographic characteristics of fish stocks that are important to recruitment: population density and age structure. First, populations produce more recruits at low density, but quantifying this response has proven difficult. Using data from hundreds of populations of walleye (Sander vitreus), an economically important freshwater fish, I demonstrate that the growing-degree-day metric (a temperature index) is better than age at explaining variation in density-dependent growth and maturity both within and among populations. I then incorporate multi-lake measures of density-dependent life history change into a temperature-based biphasic model of growth and reproduction to predict sustainable rates of mortality for walleye throughout most of their range. Second, the age (or size) structure of a population may also affect recruitment because of positive effects of maternal age on offspring production and survival; however, evidence for these ‘maternal influences’ on recruitment is limited. Using both an analytical model and a meta-analysis of stock-recruitment data from 25 species of exploited marine fish, I show that (i) maximum reproductive rate increased with the mean age of adults in a population, and (ii) the importance of age structure increased with a species’ longevity. I then demonstrate a similar effect of maternal influences on reproductive rate in a detailed study of Lake Erie walleye. By highlighting the importance of fisheries-induced demographic change to recruitment, this thesis provides insight into past and present failures. However, it also demonstrates clearly the benefits of proactive management strategies that (i) identify and respect the limits of exploitation, (ii) protect from exploitation reproductively valuable individuals—principles that apply generally to any freshwater, marine, or terrestrial species that is of recreational, commercial, or conservation value.
URI: http://hdl.handle.net/1807/19305
Appears in Collections:Doctoral
Department of Ecology & Evolutionary Biology - Doctoral theses

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