Do spatial models of growth rate potential reflect fish growth in a heterogeneous environment? A comparison of model results

Authors: Tyler J.A.¹; Brandt S.B.²

Source: Ecology of Freshwater Fish, Volume 10, Number 1, March 2001 , pp. 43-56(14)

Publisher: Wiley-Blackwell

Abstract:

Spatial models of fish growth rate potential have been used to characterize a variety of environments including estuaries, the North American Great Lakes, small lakes and rivers. Growth rate potential models capture a snapshot of the environment but do not include the effects of habitat selection or competition for food in their measures of environment quality. Here, we test the ability of spatial models of fish growth rate potential to describe the quality of an environment for a fish population in which individual fish may select habitats and local competition may affect per capita intake. We compare growth rate potential measurements to simulated fish growth and distributions of model fish from a spatially explicit individual-based model of fish foraging in the same model environment. We base the model environment on data from Lake Ontario and base the model fish population on alewife in the lake. The results from a simulation experiment show that changes in the model environment that caused changes in the average growth rate potential correlated extremely highly (r²0.97) with changes in simulated fish growth. Unfortunately, growth rate potential was not a reliable quantitative predictor of simulated fish growth nor of the fish spatial distribution. The inability of the growth rate potential model to quantitatively predict simulated fish growth and fish distributions results from the fact that growth rate potential does not consider the effects of habitat selection or of competition on fish growth or distribution, processes that operate in our individual-based model and presumably also operate in nature. The results, however, do support the use of growth rate potential models to describe the relative quality of habitats and environments for fish populations.

Keywords: growth rate potential; fish bioenergetics; individual-based model; habitat selection; habitat quality; fish growth; density dependence

Language: English

Document Type: Original article

Affiliations: 1: Worcester Polytechnic Institute, Department of Biology and Biotechnology, Worcester, Massachusetts, 2: NOAA Great Lakes Environmental Research Laboratory, Ann Arbor, Michigan, USA *

Publication date: 2001-03-01

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• In this Subject: Zoology ,  Ecology
• By this author: Tyler J.A. ;  Brandt S.B.

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