Taylor's law and body size in exploited marine ecosystems |
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Authors: | Joel E. Cohen Michael J. Plank Richard Law |
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Affiliation: | 1. Laboratory of Populations, Rockefeller & Columbia Universities, , New York, New York;2. Department of Mathematics and Statistics, University of Canterbury, , Christchurch, New Zealand;3. Department of Biology, University of York, , York, UK |
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Abstract: | Taylor's law (TL), which states that variance in population density is related to mean density via a power law, and density‐mass allometry, which states that mean density is related to body mass via a power law, are two of the most widely observed patterns in ecology. Combining these two laws predicts that the variance in density is related to body mass via a power law (variance‐mass allometry). Marine size spectra are known to exhibit density‐mass allometry, but variance‐mass allometry has not been investigated. We show that variance and body mass in unexploited size spectrum models are related by a power law, and that this leads to TL with an exponent slightly <2. These simulated relationships are disrupted less by balanced harvesting, in which fishing effort is spread across a wide range of body sizes, than by size‐at‐entry fishing, in which only fish above a certain size may legally be caught. |
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Keywords: | Balanced harvesting density‐mass allometry fishing power law size spectrum size‐at‐entry variance‐mass allometry |
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