Age readings of Sebastes marinus otoliths: bias and precision between readers and otolith preparation methods
This study presents a comparative age reading on Sebastes marinus from the Icelandic shelf within an otolith exchange program between institutes in Germany, Iceland and Norway. Out of a series of 212 otolith pairs, one otolith of each pair was prepared by the break-and-burn technique, while the othe...
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ftimr:oai:imr.brage.unit.no:11250/100637 2024-09-15T18:14:21+00:00 Age readings of Sebastes marinus otoliths: bias and precision between readers and otolith preparation methods Stransky, Christoph Guðmundsdóttir, Sif Sigurdsson, Thorsteinn Lemvig, Svend Nedreaas, Kjell Harald 2001 81968 bytes application/pdf http://hdl.handle.net/11250/100637 eng eng ICES ICES CM documents 2001/J:41 http://hdl.handle.net/11250/100637 11 s. redfish uer otoliths age determination aldersbestemmelse otolitter VDP::Mathematics and natural science: 400::Zoology and botany: 480::Marine biology: 497 Working paper 2001 ftimr 2024-07-31T03:37:25Z This study presents a comparative age reading on Sebastes marinus from the Icelandic shelf within an otolith exchange program between institutes in Germany, Iceland and Norway. Out of a series of 212 otolith pairs, one otolith of each pair was prepared by the break-and-burn technique, while the other otolith was used for crosssections. Age reading results are compared between readers and otolith preparation methods in terms of bias and precision, using a set of statistical tests and graphical methods. Significant bias was observed for both the comparison between readers and between methods, mainly caused by deviations between age scores in the higher ages (> 20 years). Precision estimates, involving the high longevity of redfish, were relatively good compared to previous age reading comparisons using other species. In contrast, the age dependent percent agreement was poor (< 30%) for a tolerance level of ± 0 years, particularly for the age range 21-30 years. A tolerance level of ± 3 years, however, lead to around 90% agreement for the age range up to 20 years. The fit of age reading scores with the von-Bertalanffy growth curve was relatively good, providing growth parameters comparable to S. marinus from the Norwegian shelf. The observed problems in bias and precision of age readings should to be improved by continuing with similar Sebastes otolith exchange programs and setting up a further age reading workshop to harmonise the interpretation of growth structures. Report Iceland Institute for Marine Research: Brage IMR |
institution |
Open Polar |
collection |
Institute for Marine Research: Brage IMR |
op_collection_id |
ftimr |
language |
English |
topic |
redfish uer otoliths age determination aldersbestemmelse otolitter VDP::Mathematics and natural science: 400::Zoology and botany: 480::Marine biology: 497 |
spellingShingle |
redfish uer otoliths age determination aldersbestemmelse otolitter VDP::Mathematics and natural science: 400::Zoology and botany: 480::Marine biology: 497 Stransky, Christoph Guðmundsdóttir, Sif Sigurdsson, Thorsteinn Lemvig, Svend Nedreaas, Kjell Harald Age readings of Sebastes marinus otoliths: bias and precision between readers and otolith preparation methods |
topic_facet |
redfish uer otoliths age determination aldersbestemmelse otolitter VDP::Mathematics and natural science: 400::Zoology and botany: 480::Marine biology: 497 |
description |
This study presents a comparative age reading on Sebastes marinus from the Icelandic shelf within an otolith exchange program between institutes in Germany, Iceland and Norway. Out of a series of 212 otolith pairs, one otolith of each pair was prepared by the break-and-burn technique, while the other otolith was used for crosssections. Age reading results are compared between readers and otolith preparation methods in terms of bias and precision, using a set of statistical tests and graphical methods. Significant bias was observed for both the comparison between readers and between methods, mainly caused by deviations between age scores in the higher ages (> 20 years). Precision estimates, involving the high longevity of redfish, were relatively good compared to previous age reading comparisons using other species. In contrast, the age dependent percent agreement was poor (< 30%) for a tolerance level of ± 0 years, particularly for the age range 21-30 years. A tolerance level of ± 3 years, however, lead to around 90% agreement for the age range up to 20 years. The fit of age reading scores with the von-Bertalanffy growth curve was relatively good, providing growth parameters comparable to S. marinus from the Norwegian shelf. The observed problems in bias and precision of age readings should to be improved by continuing with similar Sebastes otolith exchange programs and setting up a further age reading workshop to harmonise the interpretation of growth structures. |
format |
Report |
author |
Stransky, Christoph Guðmundsdóttir, Sif Sigurdsson, Thorsteinn Lemvig, Svend Nedreaas, Kjell Harald |
author_facet |
Stransky, Christoph Guðmundsdóttir, Sif Sigurdsson, Thorsteinn Lemvig, Svend Nedreaas, Kjell Harald |
author_sort |
Stransky, Christoph |
title |
Age readings of Sebastes marinus otoliths: bias and precision between readers and otolith preparation methods |
title_short |
Age readings of Sebastes marinus otoliths: bias and precision between readers and otolith preparation methods |
title_full |
Age readings of Sebastes marinus otoliths: bias and precision between readers and otolith preparation methods |
title_fullStr |
Age readings of Sebastes marinus otoliths: bias and precision between readers and otolith preparation methods |
title_full_unstemmed |
Age readings of Sebastes marinus otoliths: bias and precision between readers and otolith preparation methods |
title_sort |
age readings of sebastes marinus otoliths: bias and precision between readers and otolith preparation methods |
publisher |
ICES |
publishDate |
2001 |
url |
http://hdl.handle.net/11250/100637 |
genre |
Iceland |
genre_facet |
Iceland |
op_source |
11 s. |
op_relation |
ICES CM documents 2001/J:41 http://hdl.handle.net/11250/100637 |
_version_ |
1810452117471625216 |