Harvest-induced disruptive selection increases variance in fitness-related traits

Abstract : The form of Darwinian selection has important ecological and management implications. Negative effects of harvesting are often ascribed to size truncation (i.e. strictly directional selection against large individuals) and resultant decrease in trait variability, which depresses capacity to buffer environmental change, hinders evolutionary rebound and ultimately impairs population recovery. However, the exact form of harvest-induced selection is generally unknown and the effects of harvest on trait variability remain unexplored. Here we use unique data from the Windermere (UK) long-term ecological experiment to show in a top predator (pike, Esox lucius) that the fishery does not induce size truncation but disruptive (diversifying) selection, and does not decrease but rather increases variability in pike somatic growth rate and size at age. This result is supported by complementary modelling approaches removing the effects of catch selectivity, selection prior to the catch and environmental variation. Therefore, fishing most likely increased genetic variability for somatic growth in pike and presumably favoured an observed rapid evolutionary rebound after fishery relaxation. Inference about the mechanisms through which harvesting negatively affects population numbers and recovery should systematically be based on a measure of the exact form of selection. From a management perspective, disruptive harvesting necessitates combining a preservation of large individuals with moderate exploitation rates, and thus provides a comprehensive tool for sustainable exploitation of natural resources.
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https://hal-bioemco.ccsd.cnrs.fr/bioemco-00432166
Contributor : Eric Edeline <>
Submitted on : Friday, November 13, 2009 - 11:26:13 PM
Last modification on : Thursday, March 21, 2019 - 1:02:41 PM

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  • HAL Id : bioemco-00432166, version 1

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Eric Edeline, Arnaud Le Rouzic, Ian Winfield, Janice Fletcher, Ben James, et al.. Harvest-induced disruptive selection increases variance in fitness-related traits. Proceedings of the Royal Society B: Biological Sciences, Royal Society, The, 2009, 276 (1676), pp.4163-4171. ⟨bioemco-00432166⟩

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