In what direction should the fishing mortality target change when natural mortality increases within an assessment?
Traditionally, the natural mortality rate (M) in a stock assessment is assumed to be constant. When M increases within an assessment, the question arises how to change the fishing mortality rate target (F Target ). Per recruit considerations lead to an increase in F Target , while limiting total mor...
Published in: | Canadian Journal of Fisheries and Aquatic Sciences |
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crcansciencepubl:10.1139/cjfas-2015-0232 2024-09-15T17:55:31+00:00 In what direction should the fishing mortality target change when natural mortality increases within an assessment? Legault, Christopher M. Palmer, Michael C. Wilberg, Michael 2016 http://dx.doi.org/10.1139/cjfas-2015-0232 http://www.nrcresearchpress.com/doi/full-xml/10.1139/cjfas-2015-0232 http://www.nrcresearchpress.com/doi/pdf/10.1139/cjfas-2015-0232 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Journal of Fisheries and Aquatic Sciences volume 73, issue 3, page 349-357 ISSN 0706-652X 1205-7533 journal-article 2016 crcansciencepubl https://doi.org/10.1139/cjfas-2015-0232 2024-07-11T04:12:01Z Traditionally, the natural mortality rate (M) in a stock assessment is assumed to be constant. When M increases within an assessment, the question arises how to change the fishing mortality rate target (F Target ). Per recruit considerations lead to an increase in F Target , while limiting total mortality leads to a decrease in F Target . Application of either approach can result in nonsensical results. Short-term gains in yield associated with high F Target values should be considered in light of potential losses in future yield if the high total mortality rate leads to a decrease in recruitment. Examples using yellowtail flounder (Limanda ferruginea) and Atlantic cod (Gadus morhua) are used to demonstrate that F Target can change when M increases within an assessment and to illustrate the consequences of different F Target values. When a change in M within an assessment is contemplated, first consider the amount and strength of empirical evidence to support the change. When the empirical evidence is not strong, we recommend using a constant M. If strong empirical evidence exists, we recommend estimating F Target for a range of stock–recruitment relationships and evaluating the trade-offs between risk of overfishing and forgone yield. Article in Journal/Newspaper atlantic cod Gadus morhua Canadian Science Publishing Canadian Journal of Fisheries and Aquatic Sciences 73 3 349 357 |
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Canadian Science Publishing |
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crcansciencepubl |
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English |
description |
Traditionally, the natural mortality rate (M) in a stock assessment is assumed to be constant. When M increases within an assessment, the question arises how to change the fishing mortality rate target (F Target ). Per recruit considerations lead to an increase in F Target , while limiting total mortality leads to a decrease in F Target . Application of either approach can result in nonsensical results. Short-term gains in yield associated with high F Target values should be considered in light of potential losses in future yield if the high total mortality rate leads to a decrease in recruitment. Examples using yellowtail flounder (Limanda ferruginea) and Atlantic cod (Gadus morhua) are used to demonstrate that F Target can change when M increases within an assessment and to illustrate the consequences of different F Target values. When a change in M within an assessment is contemplated, first consider the amount and strength of empirical evidence to support the change. When the empirical evidence is not strong, we recommend using a constant M. If strong empirical evidence exists, we recommend estimating F Target for a range of stock–recruitment relationships and evaluating the trade-offs between risk of overfishing and forgone yield. |
author2 |
Wilberg, Michael |
format |
Article in Journal/Newspaper |
author |
Legault, Christopher M. Palmer, Michael C. |
spellingShingle |
Legault, Christopher M. Palmer, Michael C. In what direction should the fishing mortality target change when natural mortality increases within an assessment? |
author_facet |
Legault, Christopher M. Palmer, Michael C. |
author_sort |
Legault, Christopher M. |
title |
In what direction should the fishing mortality target change when natural mortality increases within an assessment? |
title_short |
In what direction should the fishing mortality target change when natural mortality increases within an assessment? |
title_full |
In what direction should the fishing mortality target change when natural mortality increases within an assessment? |
title_fullStr |
In what direction should the fishing mortality target change when natural mortality increases within an assessment? |
title_full_unstemmed |
In what direction should the fishing mortality target change when natural mortality increases within an assessment? |
title_sort |
in what direction should the fishing mortality target change when natural mortality increases within an assessment? |
publisher |
Canadian Science Publishing |
publishDate |
2016 |
url |
http://dx.doi.org/10.1139/cjfas-2015-0232 http://www.nrcresearchpress.com/doi/full-xml/10.1139/cjfas-2015-0232 http://www.nrcresearchpress.com/doi/pdf/10.1139/cjfas-2015-0232 |
genre |
atlantic cod Gadus morhua |
genre_facet |
atlantic cod Gadus morhua |
op_source |
Canadian Journal of Fisheries and Aquatic Sciences volume 73, issue 3, page 349-357 ISSN 0706-652X 1205-7533 |
op_rights |
http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/cjfas-2015-0232 |
container_title |
Canadian Journal of Fisheries and Aquatic Sciences |
container_volume |
73 |
container_issue |
3 |
container_start_page |
349 |
op_container_end_page |
357 |
_version_ |
1810431795529777152 |