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 |
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ftdoajarticles:oai:doaj.org/article:85042229524140daab78353987c5d90d 2023-05-15T17:45:31+02:00 Implications of life history uncertainty when evaluating status in the Northwest Atlantic population of white shark (Carcharodon carcharias) Heather D. Bowlby A. Jamie F. Gibson 2020-06-01T00:00:00Z https://doi.org/10.1002/ece3.6252 https://doaj.org/article/85042229524140daab78353987c5d90d EN eng Wiley https://doi.org/10.1002/ece3.6252 https://doaj.org/toc/2045-7758 2045-7758 doi:10.1002/ece3.6252 https://doaj.org/article/85042229524140daab78353987c5d90d Ecology and Evolution, Vol 10, Iss 11, Pp 4990-5000 (2020) endangered species conservation exploitation risk fishery removals life history analyses white shark Ecology QH540-549.5 article 2020 ftdoajarticles https://doi.org/10.1002/ece3.6252 2022-12-31T12:14:26Z 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 Directory of Open Access Journals: DOAJ Articles Ecology and Evolution 10 11 4990 5000 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
endangered species conservation exploitation risk fishery removals life history analyses white shark Ecology QH540-549.5 |
spellingShingle |
endangered species conservation exploitation risk fishery removals life history analyses white shark Ecology QH540-549.5 Heather D. Bowlby A. Jamie F. Gibson Implications of life history uncertainty when evaluating status in the Northwest Atlantic population of white shark (Carcharodon carcharias) |
topic_facet |
endangered species conservation exploitation risk fishery removals life history analyses white shark Ecology QH540-549.5 |
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 |
Heather D. Bowlby A. Jamie F. Gibson |
author_facet |
Heather D. Bowlby A. Jamie F. Gibson |
author_sort |
Heather D. Bowlby |
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 |
https://doi.org/10.1002/ece3.6252 https://doaj.org/article/85042229524140daab78353987c5d90d |
genre |
Northwest Atlantic |
genre_facet |
Northwest Atlantic |
op_source |
Ecology and Evolution, Vol 10, Iss 11, Pp 4990-5000 (2020) |
op_relation |
https://doi.org/10.1002/ece3.6252 https://doaj.org/toc/2045-7758 2045-7758 doi:10.1002/ece3.6252 https://doaj.org/article/85042229524140daab78353987c5d90d |
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_ |
1766148576478494720 |