Distribution shifts and overfishing the northern cod ( Gadus morhua): a view from the ocean
Research on northern cod (Gadus morhua) from 1983 to 1994 indicated that a southward shift in distribution in the early 1990s was real and not an artifact of sequentially fishing down local populations. In the early 1990s, seasonal fishery and survey data showed distribution changes where there was...
Published in: | Canadian Journal of Fisheries and Aquatic Sciences |
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Online Access: | http://dx.doi.org/10.1139/f00-004 http://www.nrcresearchpress.com/doi/pdf/10.1139/f00-004 |
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crcansciencepubl:10.1139/f00-004 2024-09-15T18:07:16+00:00 Distribution shifts and overfishing the northern cod ( Gadus morhua): a view from the ocean Rose, G A deYoung, B Kulka, D W Goddard, S V Fletcher, G L 2000 http://dx.doi.org/10.1139/f00-004 http://www.nrcresearchpress.com/doi/pdf/10.1139/f00-004 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Journal of Fisheries and Aquatic Sciences volume 57, issue 3, page 644-663 ISSN 0706-652X 1205-7533 journal-article 2000 crcansciencepubl https://doi.org/10.1139/f00-004 2024-08-22T04:08:45Z Research on northern cod (Gadus morhua) from 1983 to 1994 indicated that a southward shift in distribution in the early 1990s was real and not an artifact of sequentially fishing down local populations. In the early 1990s, seasonal fishery and survey data showed distribution changes where there was no fishery, and large tonnage and densities (450 000 t, densities fourfold higher than 1980s levels) appeared in the south concurrent with declines in the north. All fishery, acoustic, and trawl survey indices increased in the south, while the stock declined. Southern-caught cod in the early 1990s exhibited northern characteristics: (i) antifreeze production capacities above historical norms and equivalent to those of northern fish, (ii) vertebral counts above historic norms and equalling northern counts, and (iii) declines in size-at-age to levels associated with northern fish. The cause of the shift is thought to be a combination of abiotic (climate) and biotic (capelin (Mallotus villosus)) environmental changes and cumulative long-term fisheries effects on cod behavior. The shifted distributions increased vulnerability to Canadian and foreign fisheries and led to a rapid decline in abundance, both before and after the moratorium on fishing in Canadian waters in 1992. Rebuilding will occur in three steps: environmental restoration, recolonization by adults, and enhanced recruitment across the shelf. Article in Journal/Newspaper Gadus morhua Canadian Science Publishing Canadian Journal of Fisheries and Aquatic Sciences 57 3 644 663 |
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Open Polar |
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Canadian Science Publishing |
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crcansciencepubl |
language |
English |
description |
Research on northern cod (Gadus morhua) from 1983 to 1994 indicated that a southward shift in distribution in the early 1990s was real and not an artifact of sequentially fishing down local populations. In the early 1990s, seasonal fishery and survey data showed distribution changes where there was no fishery, and large tonnage and densities (450 000 t, densities fourfold higher than 1980s levels) appeared in the south concurrent with declines in the north. All fishery, acoustic, and trawl survey indices increased in the south, while the stock declined. Southern-caught cod in the early 1990s exhibited northern characteristics: (i) antifreeze production capacities above historical norms and equivalent to those of northern fish, (ii) vertebral counts above historic norms and equalling northern counts, and (iii) declines in size-at-age to levels associated with northern fish. The cause of the shift is thought to be a combination of abiotic (climate) and biotic (capelin (Mallotus villosus)) environmental changes and cumulative long-term fisheries effects on cod behavior. The shifted distributions increased vulnerability to Canadian and foreign fisheries and led to a rapid decline in abundance, both before and after the moratorium on fishing in Canadian waters in 1992. Rebuilding will occur in three steps: environmental restoration, recolonization by adults, and enhanced recruitment across the shelf. |
format |
Article in Journal/Newspaper |
author |
Rose, G A deYoung, B Kulka, D W Goddard, S V Fletcher, G L |
spellingShingle |
Rose, G A deYoung, B Kulka, D W Goddard, S V Fletcher, G L Distribution shifts and overfishing the northern cod ( Gadus morhua): a view from the ocean |
author_facet |
Rose, G A deYoung, B Kulka, D W Goddard, S V Fletcher, G L |
author_sort |
Rose, G A |
title |
Distribution shifts and overfishing the northern cod ( Gadus morhua): a view from the ocean |
title_short |
Distribution shifts and overfishing the northern cod ( Gadus morhua): a view from the ocean |
title_full |
Distribution shifts and overfishing the northern cod ( Gadus morhua): a view from the ocean |
title_fullStr |
Distribution shifts and overfishing the northern cod ( Gadus morhua): a view from the ocean |
title_full_unstemmed |
Distribution shifts and overfishing the northern cod ( Gadus morhua): a view from the ocean |
title_sort |
distribution shifts and overfishing the northern cod ( gadus morhua): a view from the ocean |
publisher |
Canadian Science Publishing |
publishDate |
2000 |
url |
http://dx.doi.org/10.1139/f00-004 http://www.nrcresearchpress.com/doi/pdf/10.1139/f00-004 |
genre |
Gadus morhua |
genre_facet |
Gadus morhua |
op_source |
Canadian Journal of Fisheries and Aquatic Sciences volume 57, issue 3, page 644-663 ISSN 0706-652X 1205-7533 |
op_rights |
http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/f00-004 |
container_title |
Canadian Journal of Fisheries and Aquatic Sciences |
container_volume |
57 |
container_issue |
3 |
container_start_page |
644 |
op_container_end_page |
663 |
_version_ |
1810444641327120384 |