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Estimating fishing and natural mortality rates, and catchability coefficient, from a series of observations on mean length and fishing effort

Gedamke and Hoenig (2006) (Transactions of the American Fisheries Society, 135: 476-487) developed a non-equilibrium version of the Beverton and Holt estimator of total mortality rate, Z, based on mean length and thereby increased the usefulness of length-based methods. In this study, we extend thei...

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Main Authors: Then, Amy Yee Hui, Hoenig, John Maurice, Huynh, Quang C
Format: Article
Published: Oxford University Press 2017
Subjects:
Q Science (General)
QH Natural history
Online Access:http://eprints.um.edu.my/20481/
https://doi.org/10.1093/icesjms/fsx177
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spelling my.um.eprints.204812019-02-25T07:08:31Z http://eprints.um.edu.my/20481/ Estimating fishing and natural mortality rates, and catchability coefficient, from a series of observations on mean length and fishing effort Then, Amy Yee Hui Hoenig, John Maurice Huynh, Quang C Q Science (General) QH Natural history Gedamke and Hoenig (2006) (Transactions of the American Fisheries Society, 135: 476-487) developed a non-equilibrium version of the Beverton and Holt estimator of total mortality rate, Z, based on mean length and thereby increased the usefulness of length-based methods. In this study, we extend their model by replacing period-specific Z parameters with the year-specific parameterization Z y = qf y + M where q is the catchability coefficient, f y is the fishing effort in year y, F (=qf) is the fishing mortality rate, and M is the natural mortality rate. Thus, the problem reduces to estimating just three parameters: q, M and residual variance. We used Monte Carlo simulation to study the model behaviour. Estimates of q and M are highly negatively correlated and may or may not be reliable; however, the estimates of corresponding Z's are more precise than estimates of F and are generally reliable, even when uncertainty about the mean lengths is high. This length-based method appears to work best for stocks with rapid growth rate. Contrast in effort data may not be necessary for reliable estimates of Z's. This approach forms a bridge between data-limited models and more complex models. We apply the method to the Norway lobster Nephrops norvegicus stock in Portugal as an example. Oxford University Press 2017 Article PeerReviewed Then, Amy Yee Hui and Hoenig, John Maurice and Huynh, Quang C (2017) Estimating fishing and natural mortality rates, and catchability coefficient, from a series of observations on mean length and fishing effort. ICES Journal of Marine Science, 75 (2). pp. 610-620. ISSN 1054-3139 https://doi.org/10.1093/icesjms/fsx177 doi:10.1093/icesjms/fsx177
institution Universiti Malaya
building UM Library
collection Institutional Repository
continent Asia
country Malaysia
content_provider Universiti Malaya
content_source UM Research Repository
url_provider http://eprints.um.edu.my/
topic Q Science (General)
QH Natural history
spellingShingle Q Science (General)
QH Natural history
Then, Amy Yee Hui
Hoenig, John Maurice
Huynh, Quang C
Estimating fishing and natural mortality rates, and catchability coefficient, from a series of observations on mean length and fishing effort
description Gedamke and Hoenig (2006) (Transactions of the American Fisheries Society, 135: 476-487) developed a non-equilibrium version of the Beverton and Holt estimator of total mortality rate, Z, based on mean length and thereby increased the usefulness of length-based methods. In this study, we extend their model by replacing period-specific Z parameters with the year-specific parameterization Z y = qf y + M where q is the catchability coefficient, f y is the fishing effort in year y, F (=qf) is the fishing mortality rate, and M is the natural mortality rate. Thus, the problem reduces to estimating just three parameters: q, M and residual variance. We used Monte Carlo simulation to study the model behaviour. Estimates of q and M are highly negatively correlated and may or may not be reliable; however, the estimates of corresponding Z's are more precise than estimates of F and are generally reliable, even when uncertainty about the mean lengths is high. This length-based method appears to work best for stocks with rapid growth rate. Contrast in effort data may not be necessary for reliable estimates of Z's. This approach forms a bridge between data-limited models and more complex models. We apply the method to the Norway lobster Nephrops norvegicus stock in Portugal as an example.
format Article
author Then, Amy Yee Hui
Hoenig, John Maurice
Huynh, Quang C
author_facet Then, Amy Yee Hui
Hoenig, John Maurice
Huynh, Quang C
author_sort Then, Amy Yee Hui
title Estimating fishing and natural mortality rates, and catchability coefficient, from a series of observations on mean length and fishing effort
title_short Estimating fishing and natural mortality rates, and catchability coefficient, from a series of observations on mean length and fishing effort
title_full Estimating fishing and natural mortality rates, and catchability coefficient, from a series of observations on mean length and fishing effort
title_fullStr Estimating fishing and natural mortality rates, and catchability coefficient, from a series of observations on mean length and fishing effort
title_full_unstemmed Estimating fishing and natural mortality rates, and catchability coefficient, from a series of observations on mean length and fishing effort
title_sort estimating fishing and natural mortality rates, and catchability coefficient, from a series of observations on mean length and fishing effort
publisher Oxford University Press
publishDate 2017
url http://eprints.um.edu.my/20481/
https://doi.org/10.1093/icesjms/fsx177
_version_ 1643691291898281984
score 13.211869

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