Investigating the effect of recruitment variability on length-based recruitment indices for antarctic krill using an individual-based population dynamics model.

Antarctic krill (Euphausia superba; herein krill) is monitored as part of an on-going fisheries observer program that collects length-frequency data. A krill feedback management programme is currently being developed, and as part of this development, the utility of data-derived indices describing po...

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Published in:PLoS ONE
Main Authors: Stéphane Thanassekos, Martin J Cox, Keith Reid
Format: Article in Journal/Newspaper
Language:English
Published: Public Library of Science (PLoS) 2014
Subjects:
R
Q
Online Access:https://doi.org/10.1371/journal.pone.0114378
https://doaj.org/article/39ab482cbe6c42858d14cc0809daa015
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spelling ftdoajarticles:oai:doaj.org/article:39ab482cbe6c42858d14cc0809daa015 2023-05-15T13:41:14+02:00 Investigating the effect of recruitment variability on length-based recruitment indices for antarctic krill using an individual-based population dynamics model. Stéphane Thanassekos Martin J Cox Keith Reid 2014-01-01T00:00:00Z https://doi.org/10.1371/journal.pone.0114378 https://doaj.org/article/39ab482cbe6c42858d14cc0809daa015 EN eng Public Library of Science (PLoS) http://europepmc.org/articles/PMC4254992?pdf=render https://doaj.org/toc/1932-6203 1932-6203 doi:10.1371/journal.pone.0114378 https://doaj.org/article/39ab482cbe6c42858d14cc0809daa015 PLoS ONE, Vol 9, Iss 12, p e114378 (2014) Medicine R Science Q article 2014 ftdoajarticles https://doi.org/10.1371/journal.pone.0114378 2022-12-30T20:57:52Z Antarctic krill (Euphausia superba; herein krill) is monitored as part of an on-going fisheries observer program that collects length-frequency data. A krill feedback management programme is currently being developed, and as part of this development, the utility of data-derived indices describing population level processes is being assessed. To date, however, little work has been carried out on the selection of optimum recruitment indices and it has not been possible to assess the performance of length-based recruitment indices across a range of recruitment variability. Neither has there been an assessment of uncertainty in the relationship between an index and the actual level of recruitment. Thus, until now, it has not been possible to take into account recruitment index uncertainty in krill stock management or when investigating relationships between recruitment and environmental drivers. Using length-frequency samples from a simulated population - where recruitment is known - the performance of six potential length-based recruitment indices is assessed, by exploring the index-to-recruitment relationship under increasing levels of recruitment variability (from ±10% to ±100% around a mean annual recruitment). The annual minimum of the proportion of individuals smaller than 40 mm (F40 min, %) was selected because it had the most robust index-to-recruitment relationship across differing levels of recruitment variability. The relationship was curvilinear and best described by a power law. Model uncertainty was described using the 95% prediction intervals, which were used to calculate coverage probabilities and assess model performance. Despite being the optimum recruitment index, the performance of F40 min degraded under high (>50%) recruitment variability. Due to the persistence of cohorts in the population over several years, the inclusion of F40 min values from preceding years in the relationship used to estimate recruitment in a given year improved its accuracy (mean bias reduction of 8.3% when including ... Article in Journal/Newspaper Antarc* Antarctic Antarctic Krill Euphausia superba Directory of Open Access Journals: DOAJ Articles Antarctic PLoS ONE 9 12 e114378
institution Open Polar
collection Directory of Open Access Journals: DOAJ Articles
op_collection_id ftdoajarticles
language English
topic Medicine
R
Science
Q
spellingShingle Medicine
R
Science
Q
Stéphane Thanassekos
Martin J Cox
Keith Reid
Investigating the effect of recruitment variability on length-based recruitment indices for antarctic krill using an individual-based population dynamics model.
topic_facet Medicine
R
Science
Q
description Antarctic krill (Euphausia superba; herein krill) is monitored as part of an on-going fisheries observer program that collects length-frequency data. A krill feedback management programme is currently being developed, and as part of this development, the utility of data-derived indices describing population level processes is being assessed. To date, however, little work has been carried out on the selection of optimum recruitment indices and it has not been possible to assess the performance of length-based recruitment indices across a range of recruitment variability. Neither has there been an assessment of uncertainty in the relationship between an index and the actual level of recruitment. Thus, until now, it has not been possible to take into account recruitment index uncertainty in krill stock management or when investigating relationships between recruitment and environmental drivers. Using length-frequency samples from a simulated population - where recruitment is known - the performance of six potential length-based recruitment indices is assessed, by exploring the index-to-recruitment relationship under increasing levels of recruitment variability (from ±10% to ±100% around a mean annual recruitment). The annual minimum of the proportion of individuals smaller than 40 mm (F40 min, %) was selected because it had the most robust index-to-recruitment relationship across differing levels of recruitment variability. The relationship was curvilinear and best described by a power law. Model uncertainty was described using the 95% prediction intervals, which were used to calculate coverage probabilities and assess model performance. Despite being the optimum recruitment index, the performance of F40 min degraded under high (>50%) recruitment variability. Due to the persistence of cohorts in the population over several years, the inclusion of F40 min values from preceding years in the relationship used to estimate recruitment in a given year improved its accuracy (mean bias reduction of 8.3% when including ...
format Article in Journal/Newspaper
author Stéphane Thanassekos
Martin J Cox
Keith Reid
author_facet Stéphane Thanassekos
Martin J Cox
Keith Reid
author_sort Stéphane Thanassekos
title Investigating the effect of recruitment variability on length-based recruitment indices for antarctic krill using an individual-based population dynamics model.
title_short Investigating the effect of recruitment variability on length-based recruitment indices for antarctic krill using an individual-based population dynamics model.
title_full Investigating the effect of recruitment variability on length-based recruitment indices for antarctic krill using an individual-based population dynamics model.
title_fullStr Investigating the effect of recruitment variability on length-based recruitment indices for antarctic krill using an individual-based population dynamics model.
title_full_unstemmed Investigating the effect of recruitment variability on length-based recruitment indices for antarctic krill using an individual-based population dynamics model.
title_sort investigating the effect of recruitment variability on length-based recruitment indices for antarctic krill using an individual-based population dynamics model.
publisher Public Library of Science (PLoS)
publishDate 2014
url https://doi.org/10.1371/journal.pone.0114378
https://doaj.org/article/39ab482cbe6c42858d14cc0809daa015
geographic Antarctic
geographic_facet Antarctic
genre Antarc*
Antarctic
Antarctic Krill
Euphausia superba
genre_facet Antarc*
Antarctic
Antarctic Krill
Euphausia superba
op_source PLoS ONE, Vol 9, Iss 12, p e114378 (2014)
op_relation http://europepmc.org/articles/PMC4254992?pdf=render
https://doaj.org/toc/1932-6203
1932-6203
doi:10.1371/journal.pone.0114378
https://doaj.org/article/39ab482cbe6c42858d14cc0809daa015
op_doi https://doi.org/10.1371/journal.pone.0114378
container_title PLoS ONE
container_volume 9
container_issue 12
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