Developing a size indicator for fish populations
Monitoring temporal and/or spatial variations in fish size-at-age data can often provide fisheries managers with important information about the status of fish stocks and therefore help them identify necessary changes in management policies. However, due to the multivariate nature of size-at-age dat...
Published in: | Scientia Marina |
---|---|
Main Authors: | , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Consejo Superior de Investigaciones Científicas
2008
|
Subjects: | |
Online Access: | https://doi.org/10.3989/scimar.2008.72n2221 https://doaj.org/article/3769fc0f41a74e788843078d4d1142d0 |
id |
ftdoajarticles:oai:doaj.org/article:3769fc0f41a74e788843078d4d1142d0 |
---|---|
record_format |
openpolar |
spelling |
ftdoajarticles:oai:doaj.org/article:3769fc0f41a74e788843078d4d1142d0 2023-05-15T16:19:16+02:00 Developing a size indicator for fish populations Yong Chen Xinjun Chen Liuxiong Xu 2008-06-01T00:00:00Z https://doi.org/10.3989/scimar.2008.72n2221 https://doaj.org/article/3769fc0f41a74e788843078d4d1142d0 EN eng Consejo Superior de Investigaciones Científicas http://scientiamarina.revistas.csic.es/index.php/scientiamarina/article/view/819 https://doaj.org/toc/0214-8358 https://doaj.org/toc/1886-8134 0214-8358 1886-8134 doi:10.3989/scimar.2008.72n2221 https://doaj.org/article/3769fc0f41a74e788843078d4d1142d0 Scientia Marina, Vol 72, Iss 2, Pp 221-229 (2008) size-at-age robust principal component analysis minimum volume ellipsoid analysis size indicator Aquaculture. Fisheries. Angling SH1-691 article 2008 ftdoajarticles https://doi.org/10.3989/scimar.2008.72n2221 2022-12-31T10:38:40Z Monitoring temporal and/or spatial variations in fish size-at-age data can often provide fisheries managers with important information about the status of fish stocks and therefore help them identify necessary changes in management policies. However, due to the multivariate nature of size-at-age data, commonly used single-age-based approaches ignore covariance between sizes of different age groups. Different results may therefore be derived when evaluating temporal variations using different age groups for the comparison. The possibility of atypical errors in size-at-age data due to ageing and measurement errors further complicates the comparison. We propose a two-step approach for developing an indicator for monitoring temporal and/or spatial variation in size-at-age data. A robust approach, minimum volume ellipsoid analysis, is used to identify possible outliers in size-at-age data. Then a weighted principal component analysis is applied to the data with the identified outliers down-weighted. An indicator is defined from the resultant principal components for monitoring temporal/spatial variations in size-at-age data. We illustrate the proposed approach with size-at-age data for cod (Gadus morhua) in the northwest Atlantic, NAFO subdivision 3Ps. The overall size-at-age indicator identified shows that the pre-1980 year classes tend to have a much higher size-at-age than the post-1980 year classes. Article in Journal/Newspaper Gadus morhua Northwest Atlantic Directory of Open Access Journals: DOAJ Articles Scientia Marina 72 2 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
size-at-age robust principal component analysis minimum volume ellipsoid analysis size indicator Aquaculture. Fisheries. Angling SH1-691 |
spellingShingle |
size-at-age robust principal component analysis minimum volume ellipsoid analysis size indicator Aquaculture. Fisheries. Angling SH1-691 Yong Chen Xinjun Chen Liuxiong Xu Developing a size indicator for fish populations |
topic_facet |
size-at-age robust principal component analysis minimum volume ellipsoid analysis size indicator Aquaculture. Fisheries. Angling SH1-691 |
description |
Monitoring temporal and/or spatial variations in fish size-at-age data can often provide fisheries managers with important information about the status of fish stocks and therefore help them identify necessary changes in management policies. However, due to the multivariate nature of size-at-age data, commonly used single-age-based approaches ignore covariance between sizes of different age groups. Different results may therefore be derived when evaluating temporal variations using different age groups for the comparison. The possibility of atypical errors in size-at-age data due to ageing and measurement errors further complicates the comparison. We propose a two-step approach for developing an indicator for monitoring temporal and/or spatial variation in size-at-age data. A robust approach, minimum volume ellipsoid analysis, is used to identify possible outliers in size-at-age data. Then a weighted principal component analysis is applied to the data with the identified outliers down-weighted. An indicator is defined from the resultant principal components for monitoring temporal/spatial variations in size-at-age data. We illustrate the proposed approach with size-at-age data for cod (Gadus morhua) in the northwest Atlantic, NAFO subdivision 3Ps. The overall size-at-age indicator identified shows that the pre-1980 year classes tend to have a much higher size-at-age than the post-1980 year classes. |
format |
Article in Journal/Newspaper |
author |
Yong Chen Xinjun Chen Liuxiong Xu |
author_facet |
Yong Chen Xinjun Chen Liuxiong Xu |
author_sort |
Yong Chen |
title |
Developing a size indicator for fish populations |
title_short |
Developing a size indicator for fish populations |
title_full |
Developing a size indicator for fish populations |
title_fullStr |
Developing a size indicator for fish populations |
title_full_unstemmed |
Developing a size indicator for fish populations |
title_sort |
developing a size indicator for fish populations |
publisher |
Consejo Superior de Investigaciones Científicas |
publishDate |
2008 |
url |
https://doi.org/10.3989/scimar.2008.72n2221 https://doaj.org/article/3769fc0f41a74e788843078d4d1142d0 |
genre |
Gadus morhua Northwest Atlantic |
genre_facet |
Gadus morhua Northwest Atlantic |
op_source |
Scientia Marina, Vol 72, Iss 2, Pp 221-229 (2008) |
op_relation |
http://scientiamarina.revistas.csic.es/index.php/scientiamarina/article/view/819 https://doaj.org/toc/0214-8358 https://doaj.org/toc/1886-8134 0214-8358 1886-8134 doi:10.3989/scimar.2008.72n2221 https://doaj.org/article/3769fc0f41a74e788843078d4d1142d0 |
op_doi |
https://doi.org/10.3989/scimar.2008.72n2221 |
container_title |
Scientia Marina |
container_volume |
72 |
container_issue |
2 |
_version_ |
1766005627929231360 |