Statistical catch-at-age analysis vs. ADAPT-VPA: the case of Gulf of Maine cod
Abstract Butterworth, D. S., and Rademeyer, R. A. 2008. Statistical catch-at-age analysis vs. ADAPT-VPA: the case of Gulf of Maine cod. – ICES Journal of Marine Science, 65: 1717–1732. In 2003, given an estimate of a spawning-stock biomass (Bsp) of 27% of the maximum sustainable yield (MSY) level ba...
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Online Access: | http://dx.doi.org/10.1093/icesjms/fsn178 http://academic.oup.com/icesjms/article-pdf/65/9/1717/29131540/fsn178.pdf |
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croxfordunivpr:10.1093/icesjms/fsn178 2024-04-28T08:19:36+00:00 Statistical catch-at-age analysis vs. ADAPT-VPA: the case of Gulf of Maine cod Butterworth, Doug S. Rademeyer, Rebecca A. 2008 http://dx.doi.org/10.1093/icesjms/fsn178 http://academic.oup.com/icesjms/article-pdf/65/9/1717/29131540/fsn178.pdf en eng Oxford University Press (OUP) ICES Journal of Marine Science volume 65, issue 9, page 1717-1732 ISSN 1095-9289 1054-3139 Ecology Aquatic Science Ecology, Evolution, Behavior and Systematics Oceanography journal-article 2008 croxfordunivpr https://doi.org/10.1093/icesjms/fsn178 2024-04-02T08:07:11Z Abstract Butterworth, D. S., and Rademeyer, R. A. 2008. Statistical catch-at-age analysis vs. ADAPT-VPA: the case of Gulf of Maine cod. – ICES Journal of Marine Science, 65: 1717–1732. In 2003, given an estimate of a spawning-stock biomass (Bsp) of 27% of the maximum sustainable yield (MSY) level based on an adaptive framework-virtual population analysis (ADAPT-VPA) assessment using data only after 1981, the Gulf of Maine cod (Gadus morhua) stock was deemed “overfished” under the US Magnuson–Stevens Act. However, an alternative statistical catch-at-age assessment (SCAA) at the time, using survey data from 1964, indicated Bsp above . This is investigated, together with other (sometimes conflicting) suggestions made during a number of recent assessment reviews of this stock. The primary reason for the different result is that the ADAPT-VPA assessment imposed asymptotically flat selectivity-at-age when there was strong statistical evidence for dome-shaped selectivity. Once adjusted for this, either assessment method robustly estimates Bsp relatively close to rather than below the “overfished” threshold of 0.5 . SCAA allows the longer series of survey data available to be incorporated, providing a better basis to estimate MSY-related targets and doubling the related precision in some cases. As such targets are important when implementing the Magnuson–Stevens Act, SCAA seems preferable to ADAPT-VPA for assessing this stock. Some broader inferences to be drawn from this comparative process include the need for: (i) careful treatment of the plus-group, especially if selectivity may be dome-shaped; (ii) flexible parameterizations of selectivity-at-age in SCAA to avoid false perceptions of the precision of results; and (iii) care in the use of the Beverton–Holt stock–recruitment function, as it gives inappropriately low estimates of if there is an overall negative trend in the estimates of recruitment plotted against Bsp. Article in Journal/Newspaper Gadus morhua Oxford University Press ICES Journal of Marine Science 65 9 1717 1732 |
institution |
Open Polar |
collection |
Oxford University Press |
op_collection_id |
croxfordunivpr |
language |
English |
topic |
Ecology Aquatic Science Ecology, Evolution, Behavior and Systematics Oceanography |
spellingShingle |
Ecology Aquatic Science Ecology, Evolution, Behavior and Systematics Oceanography Butterworth, Doug S. Rademeyer, Rebecca A. Statistical catch-at-age analysis vs. ADAPT-VPA: the case of Gulf of Maine cod |
topic_facet |
Ecology Aquatic Science Ecology, Evolution, Behavior and Systematics Oceanography |
description |
Abstract Butterworth, D. S., and Rademeyer, R. A. 2008. Statistical catch-at-age analysis vs. ADAPT-VPA: the case of Gulf of Maine cod. – ICES Journal of Marine Science, 65: 1717–1732. In 2003, given an estimate of a spawning-stock biomass (Bsp) of 27% of the maximum sustainable yield (MSY) level based on an adaptive framework-virtual population analysis (ADAPT-VPA) assessment using data only after 1981, the Gulf of Maine cod (Gadus morhua) stock was deemed “overfished” under the US Magnuson–Stevens Act. However, an alternative statistical catch-at-age assessment (SCAA) at the time, using survey data from 1964, indicated Bsp above . This is investigated, together with other (sometimes conflicting) suggestions made during a number of recent assessment reviews of this stock. The primary reason for the different result is that the ADAPT-VPA assessment imposed asymptotically flat selectivity-at-age when there was strong statistical evidence for dome-shaped selectivity. Once adjusted for this, either assessment method robustly estimates Bsp relatively close to rather than below the “overfished” threshold of 0.5 . SCAA allows the longer series of survey data available to be incorporated, providing a better basis to estimate MSY-related targets and doubling the related precision in some cases. As such targets are important when implementing the Magnuson–Stevens Act, SCAA seems preferable to ADAPT-VPA for assessing this stock. Some broader inferences to be drawn from this comparative process include the need for: (i) careful treatment of the plus-group, especially if selectivity may be dome-shaped; (ii) flexible parameterizations of selectivity-at-age in SCAA to avoid false perceptions of the precision of results; and (iii) care in the use of the Beverton–Holt stock–recruitment function, as it gives inappropriately low estimates of if there is an overall negative trend in the estimates of recruitment plotted against Bsp. |
format |
Article in Journal/Newspaper |
author |
Butterworth, Doug S. Rademeyer, Rebecca A. |
author_facet |
Butterworth, Doug S. Rademeyer, Rebecca A. |
author_sort |
Butterworth, Doug S. |
title |
Statistical catch-at-age analysis vs. ADAPT-VPA: the case of Gulf of Maine cod |
title_short |
Statistical catch-at-age analysis vs. ADAPT-VPA: the case of Gulf of Maine cod |
title_full |
Statistical catch-at-age analysis vs. ADAPT-VPA: the case of Gulf of Maine cod |
title_fullStr |
Statistical catch-at-age analysis vs. ADAPT-VPA: the case of Gulf of Maine cod |
title_full_unstemmed |
Statistical catch-at-age analysis vs. ADAPT-VPA: the case of Gulf of Maine cod |
title_sort |
statistical catch-at-age analysis vs. adapt-vpa: the case of gulf of maine cod |
publisher |
Oxford University Press (OUP) |
publishDate |
2008 |
url |
http://dx.doi.org/10.1093/icesjms/fsn178 http://academic.oup.com/icesjms/article-pdf/65/9/1717/29131540/fsn178.pdf |
genre |
Gadus morhua |
genre_facet |
Gadus morhua |
op_source |
ICES Journal of Marine Science volume 65, issue 9, page 1717-1732 ISSN 1095-9289 1054-3139 |
op_doi |
https://doi.org/10.1093/icesjms/fsn178 |
container_title |
ICES Journal of Marine Science |
container_volume |
65 |
container_issue |
9 |
container_start_page |
1717 |
op_container_end_page |
1732 |
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1797583016648769536 |