Constant proportion harvest policies: Dynamic implications in the Pacific halibut and Atlantic cod fisheries
a b s t r a c t Overfishing, pollution and other environmental factors have greatly reduced commercially valuable stocks of fish. In a 2006 Science article, a group of ecologists and economists warned that the world may run out of seafood from natural stocks if overfishing continues at current rates...
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ftciteseerx:oai:CiteSeerX.psu:10.1.1.1069.928 2023-05-15T15:27:07+02:00 Constant proportion harvest policies: Dynamic implications in the Pacific halibut and Atlantic cod fisheries Abdul-Aziz Yakubu Nianpeng Li Jon M Conrad Mary-Lou Zeeman The Pennsylvania State University CiteSeerX Archives application/pdf http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.1069.928 en eng http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.1069.928 Metadata may be used without restrictions as long as the oai identifier remains attached to it. https://cws.auburn.edu/shared/files?filename%3DConMan_FileDownload_FishPaper.pdf%26id%3D217 text ftciteseerx 2020-04-26T00:18:26Z a b s t r a c t Overfishing, pollution and other environmental factors have greatly reduced commercially valuable stocks of fish. In a 2006 Science article, a group of ecologists and economists warned that the world may run out of seafood from natural stocks if overfishing continues at current rates. In this paper, we explore the interaction between a constant proportion harvest policy and recruitment dynamics. We examine the discrete-time constant proportion harvest policy discussed in Ang et al. We focus on constant proportion policies (CPPs). CPPs have the potential to stabilize complex overcompensatory stock dynamics, with or without the Allee effect, provided the rates of harvest stay below a threshold. If that threshold is exceeded, CPPs are known to result in the sudden collapse of a fish stock when stock recruitment exhibits the Allee effect. In case studies, we analyze CPPs as they might be applied to Gulf of Alaska Pacific halibut fishery and the Georges Bank Atlantic cod fishery based on harvest rates from 1975 to 2007. The best fit models suggest that, under high fishing mortalities, the halibut fishery is vulnerable to sudden population collapse while the cod fishery is vulnerable to steady decline to zero. The models also suggest that CPP with mean harvesting levels from the last 30 years can be effective at preventing collapse in the halibut fishery, but these same policies would lead to steady decline to zero in the Atlantic cod fishery. We observe that the likelihood of collapse in both fisheries increases with increased stochasticity (for example, weather variability) as predicted by models of global climate change. Text atlantic cod Alaska Unknown Gulf of Alaska Pacific |
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English |
description |
a b s t r a c t Overfishing, pollution and other environmental factors have greatly reduced commercially valuable stocks of fish. In a 2006 Science article, a group of ecologists and economists warned that the world may run out of seafood from natural stocks if overfishing continues at current rates. In this paper, we explore the interaction between a constant proportion harvest policy and recruitment dynamics. We examine the discrete-time constant proportion harvest policy discussed in Ang et al. We focus on constant proportion policies (CPPs). CPPs have the potential to stabilize complex overcompensatory stock dynamics, with or without the Allee effect, provided the rates of harvest stay below a threshold. If that threshold is exceeded, CPPs are known to result in the sudden collapse of a fish stock when stock recruitment exhibits the Allee effect. In case studies, we analyze CPPs as they might be applied to Gulf of Alaska Pacific halibut fishery and the Georges Bank Atlantic cod fishery based on harvest rates from 1975 to 2007. The best fit models suggest that, under high fishing mortalities, the halibut fishery is vulnerable to sudden population collapse while the cod fishery is vulnerable to steady decline to zero. The models also suggest that CPP with mean harvesting levels from the last 30 years can be effective at preventing collapse in the halibut fishery, but these same policies would lead to steady decline to zero in the Atlantic cod fishery. We observe that the likelihood of collapse in both fisheries increases with increased stochasticity (for example, weather variability) as predicted by models of global climate change. |
author2 |
The Pennsylvania State University CiteSeerX Archives |
format |
Text |
author |
Abdul-Aziz Yakubu Nianpeng Li Jon M Conrad Mary-Lou Zeeman |
spellingShingle |
Abdul-Aziz Yakubu Nianpeng Li Jon M Conrad Mary-Lou Zeeman Constant proportion harvest policies: Dynamic implications in the Pacific halibut and Atlantic cod fisheries |
author_facet |
Abdul-Aziz Yakubu Nianpeng Li Jon M Conrad Mary-Lou Zeeman |
author_sort |
Abdul-Aziz Yakubu |
title |
Constant proportion harvest policies: Dynamic implications in the Pacific halibut and Atlantic cod fisheries |
title_short |
Constant proportion harvest policies: Dynamic implications in the Pacific halibut and Atlantic cod fisheries |
title_full |
Constant proportion harvest policies: Dynamic implications in the Pacific halibut and Atlantic cod fisheries |
title_fullStr |
Constant proportion harvest policies: Dynamic implications in the Pacific halibut and Atlantic cod fisheries |
title_full_unstemmed |
Constant proportion harvest policies: Dynamic implications in the Pacific halibut and Atlantic cod fisheries |
title_sort |
constant proportion harvest policies: dynamic implications in the pacific halibut and atlantic cod fisheries |
url |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.1069.928 |
geographic |
Gulf of Alaska Pacific |
geographic_facet |
Gulf of Alaska Pacific |
genre |
atlantic cod Alaska |
genre_facet |
atlantic cod Alaska |
op_source |
https://cws.auburn.edu/shared/files?filename%3DConMan_FileDownload_FishPaper.pdf%26id%3D217 |
op_relation |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.1069.928 |
op_rights |
Metadata may be used without restrictions as long as the oai identifier remains attached to it. |
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