Estimating illegal and unreported catches from marine ecosystems: A basis for change
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 sha...
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ftunivtasecite:oai:ecite.utas.edu.au:84076 2023-05-15T16:51:59+02:00 Estimating illegal and unreported catches from marine ecosystems: A basis for change Pitcher, TJ Watson, RA Forrest, R Valtysson, HP Guenette, S 2002 https://doi.org/10.1046/j.1467-2979.2002.00093.x http://ecite.utas.edu.au/84076 en eng Wiley-Blackwell Publishing Ltd http://dx.doi.org/10.1046/j.1467-2979.2002.00093.x Pitcher, TJ and Watson, RA and Forrest, R and Valtysson, HP and Guenette, S, Estimating illegal and unreported catches from marine ecosystems: A basis for change, Fish and Fisheries, 3, (4) pp. 317-339. ISSN 1467-2960 (2002) [Refereed Article] http://ecite.utas.edu.au/84076 Agricultural and Veterinary Sciences Fisheries Sciences Aquatic Ecosystem Studies and Stock Assessment Refereed Article PeerReviewed 2002 ftunivtasecite https://doi.org/10.1046/j.1467-2979.2002.00093.x 2019-12-13T21:48:32Z 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 Morocco catch is divided into demersal and pelagic categories. Results suggest that Icelandic cod catches may have been under-estimated 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 eCite UTAS (University of Tasmania) Southern Ocean Fish and Fisheries 3 4 317 339 |
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Open Polar |
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eCite UTAS (University of Tasmania) |
op_collection_id |
ftunivtasecite |
language |
English |
topic |
Agricultural and Veterinary Sciences Fisheries Sciences Aquatic Ecosystem Studies and Stock Assessment |
spellingShingle |
Agricultural and Veterinary Sciences Fisheries Sciences Aquatic Ecosystem Studies and Stock Assessment Pitcher, TJ Watson, RA Forrest, R Valtysson, HP Guenette, S Estimating illegal and unreported catches from marine ecosystems: A basis for change |
topic_facet |
Agricultural and Veterinary Sciences Fisheries Sciences Aquatic Ecosystem Studies and Stock Assessment |
description |
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 Morocco catch is divided into demersal and pelagic categories. Results suggest that Icelandic cod catches may have been under-estimated 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, TJ Watson, RA Forrest, R Valtysson, HP Guenette, S |
author_facet |
Pitcher, TJ Watson, RA Forrest, R Valtysson, HP Guenette, S |
author_sort |
Pitcher, TJ |
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-Blackwell Publishing Ltd |
publishDate |
2002 |
url |
https://doi.org/10.1046/j.1467-2979.2002.00093.x http://ecite.utas.edu.au/84076 |
geographic |
Southern Ocean |
geographic_facet |
Southern Ocean |
genre |
Iceland Southern Ocean |
genre_facet |
Iceland Southern Ocean |
op_relation |
http://dx.doi.org/10.1046/j.1467-2979.2002.00093.x Pitcher, TJ and Watson, RA and Forrest, R and Valtysson, HP and Guenette, S, Estimating illegal and unreported catches from marine ecosystems: A basis for change, Fish and Fisheries, 3, (4) pp. 317-339. ISSN 1467-2960 (2002) [Refereed Article] http://ecite.utas.edu.au/84076 |
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_ |
1766042122943725568 |