Allee effects and the Allee-effect zone in northwest Atlantic cod
According to the theory of compensatory dynamics, depleted populations should recover when the threat responsible for their decline is removed because per capita population growth is assumed to be highest when populations are at their smallest viable sizes. Yet, many seriously depleted fish populati...
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Online Access: | https://hdl.handle.net/11250/3001740 https://doi.org/10.1098/rsbl.2021.0439 |
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ftimr:oai:imr.brage.unit.no:11250/3001740 2023-05-15T15:27:13+02:00 Allee effects and the Allee-effect zone in northwest Atlantic cod Perälä, Tommi Hutchings, Jeffrey Kuparinen, Anna 2022 application/pdf https://hdl.handle.net/11250/3001740 https://doi.org/10.1098/rsbl.2021.0439 eng eng Biology Letters. 2022, 18 (2), . urn:issn:1744-9561 https://hdl.handle.net/11250/3001740 https://doi.org/10.1098/rsbl.2021.0439 cristin:2024399 0 18 Biology Letters 2 Peer reviewed Journal article 2022 ftimr https://doi.org/10.1098/rsbl.2021.0439 2022-07-06T22:40:30Z According to the theory of compensatory dynamics, depleted populations should recover when the threat responsible for their decline is removed because per capita population growth is assumed to be highest when populations are at their smallest viable sizes. Yet, many seriously depleted fish populations have failed to recover despite threat mitigation. Atlantic cod (Gadus morhua) stocks off Newfoundland, despite 30 years of dramatically reduced fishing mortality and numerous fishery closures, have not recovered, suggesting that drivers other than fishing can regulate the growth of collapsed fish populations, inhibiting or preventing their recovery. Here, using Bayesian inference, we show strong evidence of Allee effects in a south Newfoundland cod population, based on data on recruitment and spawning stock biomass. We infer the Allee-effect threshold, below which recovery is impaired. We demonstrate the necessity of data at low population sizes to make inferences about the nature of low-abundance dynamics. Our work indicates that Allee effects are not negligible in commercially exploited fish populations, as commonly projected, and that they represent an inhibitory force that can effectively prevent recovery from overfishing. Our findings contrast with prevailing fisheries management practices that assume compensatory dynamics at low abundances with potential to seriously overestimate the recovery potential of collapsed populations. publishedVersion Article in Journal/Newspaper atlantic cod Gadus morhua Newfoundland Northwest Atlantic Institute for Marine Research: Brage IMR Biology Letters 18 2 |
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Open Polar |
collection |
Institute for Marine Research: Brage IMR |
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ftimr |
language |
English |
description |
According to the theory of compensatory dynamics, depleted populations should recover when the threat responsible for their decline is removed because per capita population growth is assumed to be highest when populations are at their smallest viable sizes. Yet, many seriously depleted fish populations have failed to recover despite threat mitigation. Atlantic cod (Gadus morhua) stocks off Newfoundland, despite 30 years of dramatically reduced fishing mortality and numerous fishery closures, have not recovered, suggesting that drivers other than fishing can regulate the growth of collapsed fish populations, inhibiting or preventing their recovery. Here, using Bayesian inference, we show strong evidence of Allee effects in a south Newfoundland cod population, based on data on recruitment and spawning stock biomass. We infer the Allee-effect threshold, below which recovery is impaired. We demonstrate the necessity of data at low population sizes to make inferences about the nature of low-abundance dynamics. Our work indicates that Allee effects are not negligible in commercially exploited fish populations, as commonly projected, and that they represent an inhibitory force that can effectively prevent recovery from overfishing. Our findings contrast with prevailing fisheries management practices that assume compensatory dynamics at low abundances with potential to seriously overestimate the recovery potential of collapsed populations. publishedVersion |
format |
Article in Journal/Newspaper |
author |
Perälä, Tommi Hutchings, Jeffrey Kuparinen, Anna |
spellingShingle |
Perälä, Tommi Hutchings, Jeffrey Kuparinen, Anna Allee effects and the Allee-effect zone in northwest Atlantic cod |
author_facet |
Perälä, Tommi Hutchings, Jeffrey Kuparinen, Anna |
author_sort |
Perälä, Tommi |
title |
Allee effects and the Allee-effect zone in northwest Atlantic cod |
title_short |
Allee effects and the Allee-effect zone in northwest Atlantic cod |
title_full |
Allee effects and the Allee-effect zone in northwest Atlantic cod |
title_fullStr |
Allee effects and the Allee-effect zone in northwest Atlantic cod |
title_full_unstemmed |
Allee effects and the Allee-effect zone in northwest Atlantic cod |
title_sort |
allee effects and the allee-effect zone in northwest atlantic cod |
publishDate |
2022 |
url |
https://hdl.handle.net/11250/3001740 https://doi.org/10.1098/rsbl.2021.0439 |
genre |
atlantic cod Gadus morhua Newfoundland Northwest Atlantic |
genre_facet |
atlantic cod Gadus morhua Newfoundland Northwest Atlantic |
op_source |
0 18 Biology Letters 2 |
op_relation |
Biology Letters. 2022, 18 (2), . urn:issn:1744-9561 https://hdl.handle.net/11250/3001740 https://doi.org/10.1098/rsbl.2021.0439 cristin:2024399 |
op_doi |
https://doi.org/10.1098/rsbl.2021.0439 |
container_title |
Biology Letters |
container_volume |
18 |
container_issue |
2 |
_version_ |
1766357673428647936 |