Implications of life history uncertainty when evaluating status in the Northwest Atlantic population of white shark ( Carcharodon carcharias)
Abstract To effectively protect at‐risk sharks, resource managers and conservation practitioners must have a good understanding of how fisheries removals contribute to changes in abundance and how regulatory restrictions may impact a population trajectory. This means they need to know the number of...
Published in: | Ecology and Evolution |
---|---|
Main Authors: | , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Wiley
2020
|
Subjects: | |
Online Access: | http://dx.doi.org/10.1002/ece3.6252 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fece3.6252 https://onlinelibrary.wiley.com/doi/pdf/10.1002/ece3.6252 https://onlinelibrary.wiley.com/doi/full-xml/10.1002/ece3.6252 |
id |
crwiley:10.1002/ece3.6252 |
---|---|
record_format |
openpolar |
spelling |
crwiley:10.1002/ece3.6252 2024-06-02T08:12:15+00:00 Implications of life history uncertainty when evaluating status in the Northwest Atlantic population of white shark ( Carcharodon carcharias) Bowlby, Heather D. Gibson, A. Jamie F. 2020 http://dx.doi.org/10.1002/ece3.6252 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fece3.6252 https://onlinelibrary.wiley.com/doi/pdf/10.1002/ece3.6252 https://onlinelibrary.wiley.com/doi/full-xml/10.1002/ece3.6252 en eng Wiley http://creativecommons.org/licenses/by/4.0/ Ecology and Evolution volume 10, issue 11, page 4990-5000 ISSN 2045-7758 2045-7758 journal-article 2020 crwiley https://doi.org/10.1002/ece3.6252 2024-05-03T11:44:09Z Abstract To effectively protect at‐risk sharks, resource managers and conservation practitioners must have a good understanding of how fisheries removals contribute to changes in abundance and how regulatory restrictions may impact a population trajectory. This means they need to know the number of animals being removed from a population and whether a given number of removals will lead to population increases or declines. For white shark ( Carcharodon carcharias ), theoretical quantities like the intrinsic rate of population increase or rebound potential (ability to increase in size following decline) are difficult to conceptualize in terms of real‐world abundance changes, which limits our ability to answer practical management questions. To address this shortfall, we designed a simulation model to evaluate how our understanding of longevity and life history variability of white shark affects our understanding of population trends in the Northwest Atlantic. Then, we quantified the magnitude of removals that could have caused historical population declines, compared these to biologically based reference points, and explored the removal scenarios which would result in population increase. Our results suggest that removals on the order of 100s of juveniles per year could have resulted in population‐level declines in excess of 60% during the 1970s and 1980s. Conservation actions implemented since the 1990s would have needed to be nearly 100% effective at preventing fishing mortality in order for the population to double in abundance over the last 30 years. Total removals from all fleets needed to be exceptionally small to keep them below biological reference points for white shark in the Northwest Atlantic. The population's inherent vulnerability to fishing pressure reaffirms the need for restrictive national and international conservation measures, even under a situation of abundance increase. Article in Journal/Newspaper Northwest Atlantic Wiley Online Library Ecology and Evolution 10 11 4990 5000 |
institution |
Open Polar |
collection |
Wiley Online Library |
op_collection_id |
crwiley |
language |
English |
description |
Abstract To effectively protect at‐risk sharks, resource managers and conservation practitioners must have a good understanding of how fisheries removals contribute to changes in abundance and how regulatory restrictions may impact a population trajectory. This means they need to know the number of animals being removed from a population and whether a given number of removals will lead to population increases or declines. For white shark ( Carcharodon carcharias ), theoretical quantities like the intrinsic rate of population increase or rebound potential (ability to increase in size following decline) are difficult to conceptualize in terms of real‐world abundance changes, which limits our ability to answer practical management questions. To address this shortfall, we designed a simulation model to evaluate how our understanding of longevity and life history variability of white shark affects our understanding of population trends in the Northwest Atlantic. Then, we quantified the magnitude of removals that could have caused historical population declines, compared these to biologically based reference points, and explored the removal scenarios which would result in population increase. Our results suggest that removals on the order of 100s of juveniles per year could have resulted in population‐level declines in excess of 60% during the 1970s and 1980s. Conservation actions implemented since the 1990s would have needed to be nearly 100% effective at preventing fishing mortality in order for the population to double in abundance over the last 30 years. Total removals from all fleets needed to be exceptionally small to keep them below biological reference points for white shark in the Northwest Atlantic. The population's inherent vulnerability to fishing pressure reaffirms the need for restrictive national and international conservation measures, even under a situation of abundance increase. |
format |
Article in Journal/Newspaper |
author |
Bowlby, Heather D. Gibson, A. Jamie F. |
spellingShingle |
Bowlby, Heather D. Gibson, A. Jamie F. Implications of life history uncertainty when evaluating status in the Northwest Atlantic population of white shark ( Carcharodon carcharias) |
author_facet |
Bowlby, Heather D. Gibson, A. Jamie F. |
author_sort |
Bowlby, Heather D. |
title |
Implications of life history uncertainty when evaluating status in the Northwest Atlantic population of white shark ( Carcharodon carcharias) |
title_short |
Implications of life history uncertainty when evaluating status in the Northwest Atlantic population of white shark ( Carcharodon carcharias) |
title_full |
Implications of life history uncertainty when evaluating status in the Northwest Atlantic population of white shark ( Carcharodon carcharias) |
title_fullStr |
Implications of life history uncertainty when evaluating status in the Northwest Atlantic population of white shark ( Carcharodon carcharias) |
title_full_unstemmed |
Implications of life history uncertainty when evaluating status in the Northwest Atlantic population of white shark ( Carcharodon carcharias) |
title_sort |
implications of life history uncertainty when evaluating status in the northwest atlantic population of white shark ( carcharodon carcharias) |
publisher |
Wiley |
publishDate |
2020 |
url |
http://dx.doi.org/10.1002/ece3.6252 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fece3.6252 https://onlinelibrary.wiley.com/doi/pdf/10.1002/ece3.6252 https://onlinelibrary.wiley.com/doi/full-xml/10.1002/ece3.6252 |
genre |
Northwest Atlantic |
genre_facet |
Northwest Atlantic |
op_source |
Ecology and Evolution volume 10, issue 11, page 4990-5000 ISSN 2045-7758 2045-7758 |
op_rights |
http://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.1002/ece3.6252 |
container_title |
Ecology and Evolution |
container_volume |
10 |
container_issue |
11 |
container_start_page |
4990 |
op_container_end_page |
5000 |
_version_ |
1800758633019998208 |