Density dependence only affects increase rates in baleen whale populations at high abundance levels

Abstract Most baleen whale populations are increasing after the end of industrial whaling, but their recovery patterns challenge long‐standing assumptions about density dependence. It has long been assumed that population growth rates will decline with recovery, until reaching equilibrium (‘carrying...

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Published in:Journal of Applied Ecology
Main Authors: Kanaji, Yu, Williams, Rob, Zerbini, Alexandre N., Branch, Trevor A.
Format: Article in Journal/Newspaper
Language:English
Published: Wiley 2024
Subjects:
Online Access:http://dx.doi.org/10.1111/1365-2664.14744
https://besjournals.onlinelibrary.wiley.com/doi/pdf/10.1111/1365-2664.14744
id crwiley:10.1111/1365-2664.14744
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spelling crwiley:10.1111/1365-2664.14744 2024-09-30T14:32:45+00:00 Density dependence only affects increase rates in baleen whale populations at high abundance levels Kanaji, Yu Williams, Rob Zerbini, Alexandre N. Branch, Trevor A. 2024 http://dx.doi.org/10.1111/1365-2664.14744 https://besjournals.onlinelibrary.wiley.com/doi/pdf/10.1111/1365-2664.14744 en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Journal of Applied Ecology ISSN 0021-8901 1365-2664 journal-article 2024 crwiley https://doi.org/10.1111/1365-2664.14744 2024-09-05T05:06:49Z Abstract Most baleen whale populations are increasing after the end of industrial whaling, but their recovery patterns challenge long‐standing assumptions about density dependence. It has long been assumed that population growth rates will decline with recovery, until reaching equilibrium (‘carrying capacity’, K ). Indeed, the International Whaling Commission assumes that growth rates will slow long before K is reached, with maximum productivity at 0.6 K . This 0.6 K population level is used as an international benchmark that forms the basis of whaling regulations and decisions about whether baleen whale populations are declared depleted. We fit models to four long‐term data sets for baleen whales with multiple abundance estimates that span the range from low to high abundance, finding strong evidence that increase rates remain at near‐maximal levels across a wide range of abundance levels, and only decline as the population nears K . As a result, maximum productivity occurs at 0.69–0.87 of K across these populations, which predicts more rapid recovery for baleen whale populations than currently assumed. The overall mean of these values (0.8 K ) would be a more sensible default choice than the 0.6 K currently assumed. Synthesis and applications . Estimated recovery rates imply that management thresholds currently used are lower than actual maximum productivity and that populations can increase rapidly even at high abundance. However, if population models continue to assume that maximum productivity is at 0.6 K , they will estimate abundance relative to K to be lower than it is, providing conservative assessment results. Our results should stimulate further discussion about the role of maximum sustainable yield as a fundamental concept in fisheries and wildlife management. Article in Journal/Newspaper baleen whale baleen whales Wiley Online Library Journal of Applied Ecology 61 9 2258 2269
institution Open Polar
collection Wiley Online Library
op_collection_id crwiley
language English
description Abstract Most baleen whale populations are increasing after the end of industrial whaling, but their recovery patterns challenge long‐standing assumptions about density dependence. It has long been assumed that population growth rates will decline with recovery, until reaching equilibrium (‘carrying capacity’, K ). Indeed, the International Whaling Commission assumes that growth rates will slow long before K is reached, with maximum productivity at 0.6 K . This 0.6 K population level is used as an international benchmark that forms the basis of whaling regulations and decisions about whether baleen whale populations are declared depleted. We fit models to four long‐term data sets for baleen whales with multiple abundance estimates that span the range from low to high abundance, finding strong evidence that increase rates remain at near‐maximal levels across a wide range of abundance levels, and only decline as the population nears K . As a result, maximum productivity occurs at 0.69–0.87 of K across these populations, which predicts more rapid recovery for baleen whale populations than currently assumed. The overall mean of these values (0.8 K ) would be a more sensible default choice than the 0.6 K currently assumed. Synthesis and applications . Estimated recovery rates imply that management thresholds currently used are lower than actual maximum productivity and that populations can increase rapidly even at high abundance. However, if population models continue to assume that maximum productivity is at 0.6 K , they will estimate abundance relative to K to be lower than it is, providing conservative assessment results. Our results should stimulate further discussion about the role of maximum sustainable yield as a fundamental concept in fisheries and wildlife management.
format Article in Journal/Newspaper
author Kanaji, Yu
Williams, Rob
Zerbini, Alexandre N.
Branch, Trevor A.
spellingShingle Kanaji, Yu
Williams, Rob
Zerbini, Alexandre N.
Branch, Trevor A.
Density dependence only affects increase rates in baleen whale populations at high abundance levels
author_facet Kanaji, Yu
Williams, Rob
Zerbini, Alexandre N.
Branch, Trevor A.
author_sort Kanaji, Yu
title Density dependence only affects increase rates in baleen whale populations at high abundance levels
title_short Density dependence only affects increase rates in baleen whale populations at high abundance levels
title_full Density dependence only affects increase rates in baleen whale populations at high abundance levels
title_fullStr Density dependence only affects increase rates in baleen whale populations at high abundance levels
title_full_unstemmed Density dependence only affects increase rates in baleen whale populations at high abundance levels
title_sort density dependence only affects increase rates in baleen whale populations at high abundance levels
publisher Wiley
publishDate 2024
url http://dx.doi.org/10.1111/1365-2664.14744
https://besjournals.onlinelibrary.wiley.com/doi/pdf/10.1111/1365-2664.14744
genre baleen whale
baleen whales
genre_facet baleen whale
baleen whales
op_source Journal of Applied Ecology
ISSN 0021-8901 1365-2664
op_rights http://onlinelibrary.wiley.com/termsAndConditions#vor
op_doi https://doi.org/10.1111/1365-2664.14744
container_title Journal of Applied Ecology
container_volume 61
container_issue 9
container_start_page 2258
op_container_end_page 2269
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