Estimating illegal and unreported catches from marine ecosystems: a basis for change
Abstract To evaluate the impacts of fishing on marine ecosystems, the total extraction of fish must be known. Putting a figure on total extraction entails the difficult task of estimating, in addition to reported landings, discards, illegal and unmandated catches. Unreported catches cast various typ...
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crwiley:10.1046/j.1467-2979.2002.00093.x 2024-09-15T18:14:23+00:00 Estimating illegal and unreported catches from marine ecosystems: a basis for change Pitcher, Tony J Watson, Reg Forrest, Robyn Valtýsson, Hreiðar Þór Guénette, Sylvie 2002 http://dx.doi.org/10.1046/j.1467-2979.2002.00093.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1046%2Fj.1467-2979.2002.00093.x https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1467-2979.2002.00093.x en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Fish and Fisheries volume 3, issue 4, page 317-339 ISSN 1467-2960 1467-2979 journal-article 2002 crwiley https://doi.org/10.1046/j.1467-2979.2002.00093.x 2024-08-15T04:21:04Z Abstract To evaluate the impacts of fishing on marine ecosystems, the total extraction of fish must be known. Putting a figure on total extraction entails the difficult task of estimating, in addition to reported landings, discards, illegal and unmandated catches. Unreported catches cast various types of shadow, which may be tracked and estimated quantitatively. Some shadows of unreported catches are reviewed, for example, an innovative, well‐funded NGO publicizes illegal catch in the Southern Ocean. For various reasons, official figures often have the implicit but unacceptable assumption that such categories are null. We present an estimation procedure based on adjustment factors taken from observer reports, correspondents and published information that track changes in a regulatory regime, and hence reflect incentives and disincentives to misreport. Monte Carlo simulations address uncertainty using multiple sources of information to provide upper and lower estimates. Once in place, this method provides preliminary estimates that may be refined without disruption. The method is demonstrated for fisheries in Iceland and Morocco. We use a ‘by‐species’ approach for Icelandic cod and haddock, while the Moroccan catch is divided into demersal and pelagic categories. Results suggest that Icelandic cod catches may have been underestimated by between 1 and 14% at different times, and haddock by between 1 and 28%. Underestimation of Moroccan catches appears to have been as much as by 50%. These case studies show that it is possible to obtain estimates of misreporting, even when direct data are lacking. Our method encourages transparency because sources of information are presented so that uncertain values are easily identified, offering a basis for comment, collaboration and refinement in estimating illegal and unreported fishing. Article in Journal/Newspaper Iceland Southern Ocean Wiley Online Library Fish and Fisheries 3 4 317 339 |
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Wiley Online Library |
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English |
description |
Abstract To evaluate the impacts of fishing on marine ecosystems, the total extraction of fish must be known. Putting a figure on total extraction entails the difficult task of estimating, in addition to reported landings, discards, illegal and unmandated catches. Unreported catches cast various types of shadow, which may be tracked and estimated quantitatively. Some shadows of unreported catches are reviewed, for example, an innovative, well‐funded NGO publicizes illegal catch in the Southern Ocean. For various reasons, official figures often have the implicit but unacceptable assumption that such categories are null. We present an estimation procedure based on adjustment factors taken from observer reports, correspondents and published information that track changes in a regulatory regime, and hence reflect incentives and disincentives to misreport. Monte Carlo simulations address uncertainty using multiple sources of information to provide upper and lower estimates. Once in place, this method provides preliminary estimates that may be refined without disruption. The method is demonstrated for fisheries in Iceland and Morocco. We use a ‘by‐species’ approach for Icelandic cod and haddock, while the Moroccan catch is divided into demersal and pelagic categories. Results suggest that Icelandic cod catches may have been underestimated by between 1 and 14% at different times, and haddock by between 1 and 28%. Underestimation of Moroccan catches appears to have been as much as by 50%. These case studies show that it is possible to obtain estimates of misreporting, even when direct data are lacking. Our method encourages transparency because sources of information are presented so that uncertain values are easily identified, offering a basis for comment, collaboration and refinement in estimating illegal and unreported fishing. |
format |
Article in Journal/Newspaper |
author |
Pitcher, Tony J Watson, Reg Forrest, Robyn Valtýsson, Hreiðar Þór Guénette, Sylvie |
spellingShingle |
Pitcher, Tony J Watson, Reg Forrest, Robyn Valtýsson, Hreiðar Þór Guénette, Sylvie Estimating illegal and unreported catches from marine ecosystems: a basis for change |
author_facet |
Pitcher, Tony J Watson, Reg Forrest, Robyn Valtýsson, Hreiðar Þór Guénette, Sylvie |
author_sort |
Pitcher, Tony J |
title |
Estimating illegal and unreported catches from marine ecosystems: a basis for change |
title_short |
Estimating illegal and unreported catches from marine ecosystems: a basis for change |
title_full |
Estimating illegal and unreported catches from marine ecosystems: a basis for change |
title_fullStr |
Estimating illegal and unreported catches from marine ecosystems: a basis for change |
title_full_unstemmed |
Estimating illegal and unreported catches from marine ecosystems: a basis for change |
title_sort |
estimating illegal and unreported catches from marine ecosystems: a basis for change |
publisher |
Wiley |
publishDate |
2002 |
url |
http://dx.doi.org/10.1046/j.1467-2979.2002.00093.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1046%2Fj.1467-2979.2002.00093.x https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1467-2979.2002.00093.x |
genre |
Iceland Southern Ocean |
genre_facet |
Iceland Southern Ocean |
op_source |
Fish and Fisheries volume 3, issue 4, page 317-339 ISSN 1467-2960 1467-2979 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1046/j.1467-2979.2002.00093.x |
container_title |
Fish and Fisheries |
container_volume |
3 |
container_issue |
4 |
container_start_page |
317 |
op_container_end_page |
339 |
_version_ |
1810452151351115776 |