Declining Weight-at-age in Northern Cod and the Potential Importance of the Early Years and Size-selective Fishing Mortality
Weight-at-age of northern cod (Gadus morhua) declined between 1979 and 1993 for all age-classes, with the greatest reduction in size-specific growth evident at ages 3, 4 and 5. The extent to which the declines in weights at these young ages have been responsible for smaller weights in older age-clas...
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ftciteseerx:oai:CiteSeerX.psu:10.1.1.568.9911 2023-05-15T15:27:34+02:00 Declining Weight-at-age in Northern Cod and the Potential Importance of the Early Years and Size-selective Fishing Mortality Martha M. Krohn Stephen R. Kerr The Pennsylvania State University CiteSeerX Archives application/pdf http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.568.9911 http://archive.nafo.int/open/studies/s29/krohn.pdf en eng http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.568.9911 http://archive.nafo.int/open/studies/s29/krohn.pdf Metadata may be used without restrictions as long as the oai identifier remains attached to it. http://archive.nafo.int/open/studies/s29/krohn.pdf Key words Atlantic cod growth size-specific growth text ftciteseerx 2016-01-08T12:24:01Z Weight-at-age of northern cod (Gadus morhua) declined between 1979 and 1993 for all age-classes, with the greatest reduction in size-specific growth evident at ages 3, 4 and 5. The extent to which the declines in weights at these young ages have been responsible for smaller weights in older age-classes was determined. On average 68 % of the decline in weight of 4- to 8-year-olds was attributable to a decline in weight-at-age in previous years. Differences in weight-at-age among cohorts suggested that cohorts that are small early in life tend to remain small, and that size in early years greatly influences future production. These findings suggest that the environment for growth may have worsened specifically for these young ages, highlighting the importance of studying what is affecting growth processes in the early years. These results also point to the possibility that size-selective fishing on the 3- to 5-year-olds may have played an important role in the decline in weight-at-age. Text atlantic cod Gadus morhua Unknown |
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English |
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Key words Atlantic cod growth size-specific growth |
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Key words Atlantic cod growth size-specific growth Martha M. Krohn Stephen R. Kerr Declining Weight-at-age in Northern Cod and the Potential Importance of the Early Years and Size-selective Fishing Mortality |
topic_facet |
Key words Atlantic cod growth size-specific growth |
description |
Weight-at-age of northern cod (Gadus morhua) declined between 1979 and 1993 for all age-classes, with the greatest reduction in size-specific growth evident at ages 3, 4 and 5. The extent to which the declines in weights at these young ages have been responsible for smaller weights in older age-classes was determined. On average 68 % of the decline in weight of 4- to 8-year-olds was attributable to a decline in weight-at-age in previous years. Differences in weight-at-age among cohorts suggested that cohorts that are small early in life tend to remain small, and that size in early years greatly influences future production. These findings suggest that the environment for growth may have worsened specifically for these young ages, highlighting the importance of studying what is affecting growth processes in the early years. These results also point to the possibility that size-selective fishing on the 3- to 5-year-olds may have played an important role in the decline in weight-at-age. |
author2 |
The Pennsylvania State University CiteSeerX Archives |
format |
Text |
author |
Martha M. Krohn Stephen R. Kerr |
author_facet |
Martha M. Krohn Stephen R. Kerr |
author_sort |
Martha M. Krohn |
title |
Declining Weight-at-age in Northern Cod and the Potential Importance of the Early Years and Size-selective Fishing Mortality |
title_short |
Declining Weight-at-age in Northern Cod and the Potential Importance of the Early Years and Size-selective Fishing Mortality |
title_full |
Declining Weight-at-age in Northern Cod and the Potential Importance of the Early Years and Size-selective Fishing Mortality |
title_fullStr |
Declining Weight-at-age in Northern Cod and the Potential Importance of the Early Years and Size-selective Fishing Mortality |
title_full_unstemmed |
Declining Weight-at-age in Northern Cod and the Potential Importance of the Early Years and Size-selective Fishing Mortality |
title_sort |
declining weight-at-age in northern cod and the potential importance of the early years and size-selective fishing mortality |
url |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.568.9911 http://archive.nafo.int/open/studies/s29/krohn.pdf |
genre |
atlantic cod Gadus morhua |
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atlantic cod Gadus morhua |
op_source |
http://archive.nafo.int/open/studies/s29/krohn.pdf |
op_relation |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.568.9911 http://archive.nafo.int/open/studies/s29/krohn.pdf |
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Metadata may be used without restrictions as long as the oai identifier remains attached to it. |
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