Dynamics of spawning migrations in Northeast Arctic cod
The Northeast Arctic (NA) cod is known to undertake long southbound spawning migrations from their feeding grounds in the Barents Sea, to various spawning grounds along the Norwegian coast. Hence it’s native Norwegian name “skrei”, meaning to move or to travel. The spawned eggs and larvae subsequent...
Published in: | Ecology |
---|---|
Main Author: | |
Format: | Doctoral or Postdoctoral Thesis |
Language: | English |
Published: |
The University of Bergen
2010
|
Subjects: | |
Online Access: | http://hdl.handle.net/1956/4583 |
id |
ftunivbergen:oai:bora.uib.no:1956/4583 |
---|---|
record_format |
openpolar |
institution |
Open Polar |
collection |
University of Bergen: Bergen Open Research Archive (BORA-UiB) |
op_collection_id |
ftunivbergen |
language |
English |
topic |
VDP::Mathematics and natural science: 400::Zoology and botany: 480::Marine biology: 497 |
spellingShingle |
VDP::Mathematics and natural science: 400::Zoology and botany: 480::Marine biology: 497 Opdal, Anders Frugård Dynamics of spawning migrations in Northeast Arctic cod |
topic_facet |
VDP::Mathematics and natural science: 400::Zoology and botany: 480::Marine biology: 497 |
description |
The Northeast Arctic (NA) cod is known to undertake long southbound spawning migrations from their feeding grounds in the Barents Sea, to various spawning grounds along the Norwegian coast. Hence it’s native Norwegian name “skrei”, meaning to move or to travel. The spawned eggs and larvae subsequently drift northwards along with the prevailing currents, eventually reaching the Barents Sea as juveniles. From commercial fisheries statistics we see that these spawning grounds once spanned across nearly 2000 km of the west coast of Norway, from Finnmark in the north to Vest-Agder at the very south. Today the latitudinal range of the spawning grounds is significantly reduced, with only a marginal part of the stock spawning as far south as Møre, some 1500 km from the Barents Sea. Coarse estimates from the Institute of Marine Research suggest that around 90 - 95 % of the spawning stock spawn from Lofoten and northwards, utilizing only a third of their original expanse. Also, recent scientific surveys have found that during the last decade, the NA cod have to a great extent stopped spawning at their major traditional grounds in Vestfjorden, Lofoten, and have relocated to more northbound areas. Historically, scientists have shown little interest in the changes in spawning grounds, but due to the major impact this recent shift has had on local fishermen and landing ports, the topic currently attracts noticeable interest from fisheries scientists as well as climate scientists. The NA cod’s previous widespread spawning distribution, together with its historical and contemporary northbound shifts has spurred two major research questions addressed in this thesis. First, why does spawning take place over such a vast geographical area, implying that certain parts of the population undergo spawning migrations several thousands of kilometres further than their conspecifics? Secondly, what has caused the northbound shift in spawning grounds? From general evolutionary theory, we would expect that individuals undertaking longer ... |
format |
Doctoral or Postdoctoral Thesis |
author |
Opdal, Anders Frugård |
author_facet |
Opdal, Anders Frugård |
author_sort |
Opdal, Anders Frugård |
title |
Dynamics of spawning migrations in Northeast Arctic cod |
title_short |
Dynamics of spawning migrations in Northeast Arctic cod |
title_full |
Dynamics of spawning migrations in Northeast Arctic cod |
title_fullStr |
Dynamics of spawning migrations in Northeast Arctic cod |
title_full_unstemmed |
Dynamics of spawning migrations in Northeast Arctic cod |
title_sort |
dynamics of spawning migrations in northeast arctic cod |
publisher |
The University of Bergen |
publishDate |
2010 |
url |
http://hdl.handle.net/1956/4583 |
geographic |
Arctic Barents Sea Lofoten Norway |
geographic_facet |
Arctic Barents Sea Lofoten Norway |
genre |
Arctic Arctic cod Arctic Barents Sea Finnmark Lofoten Northeast Arctic cod Vestfjorden Finnmark Skrei |
genre_facet |
Arctic Arctic cod Arctic Barents Sea Finnmark Lofoten Northeast Arctic cod Vestfjorden Finnmark Skrei |
op_relation |
PAPER I: Ecology 89(12), Jørgensen, C.; Dunlop, E.; Opdal, A. F.; and Fiksen, Ø., The evolution of spawning migrations: state dependence and fishing-induced changes, pp. 3436-3448. Published version. Copyright 2008 by the Ecological Society of America. The published version is also available at: http://dx.doi.org/10.1890/07-1469.1 PAPER II: Journal of Northwest Atlantic Fishery Science 49, Opdal, A. F.; Vikebø, F. B.; and Fiksen, Ø., Relationships between spawning ground identity, latitude and early life thermal exposure in Northeast Arctic cod, pp. 13-22. Published version. Copyright 2008 the authors. Published under the Creative Commons Attribution-Non Commercial 2.5 Canada Licence. The published version is also available at: http://dx.doi.org/10.2960/J.v41.m621 PAPER III: Biology Letters 6(2), Opdal, A. F., Fisheries change spawning ground distribution of northeast Arctic cod, pp. 261-264. Copyright 2009 The Royal Society. Published version. Full text not available in BORA due to publisher restrictions. The published version is available at: http://dx.doi.org/10.1098/rsbl.2009.0789 PAPER IV: Opdal, A. F.; Vikebø, F. B. and Fiksen, Ø. (2010), Historical changes in spawning grounds of Northeast Arctic cod outweigh role of climatic variation for early life thermal exposure. Draft version. Full text not available in BORA. urn:isbn:978-82-308-1662-2 (print version) http://hdl.handle.net/1956/4583 |
op_rights |
The author Copyright the author. All rights reserved |
op_doi |
https://doi.org/10.1890/07-1469.110.2960/J.v41.m62110.1098/rsbl.2009.0789 |
container_title |
Ecology |
container_volume |
89 |
container_issue |
12 |
container_start_page |
3436 |
op_container_end_page |
3448 |
_version_ |
1766300630242033664 |
spelling |
ftunivbergen:oai:bora.uib.no:1956/4583 2023-05-15T14:27:04+02:00 Dynamics of spawning migrations in Northeast Arctic cod Opdal, Anders Frugård 2010-12-10 application/pdf http://hdl.handle.net/1956/4583 eng eng The University of Bergen PAPER I: Ecology 89(12), Jørgensen, C.; Dunlop, E.; Opdal, A. F.; and Fiksen, Ø., The evolution of spawning migrations: state dependence and fishing-induced changes, pp. 3436-3448. Published version. Copyright 2008 by the Ecological Society of America. The published version is also available at: http://dx.doi.org/10.1890/07-1469.1 PAPER II: Journal of Northwest Atlantic Fishery Science 49, Opdal, A. F.; Vikebø, F. B.; and Fiksen, Ø., Relationships between spawning ground identity, latitude and early life thermal exposure in Northeast Arctic cod, pp. 13-22. Published version. Copyright 2008 the authors. Published under the Creative Commons Attribution-Non Commercial 2.5 Canada Licence. The published version is also available at: http://dx.doi.org/10.2960/J.v41.m621 PAPER III: Biology Letters 6(2), Opdal, A. F., Fisheries change spawning ground distribution of northeast Arctic cod, pp. 261-264. Copyright 2009 The Royal Society. Published version. Full text not available in BORA due to publisher restrictions. The published version is available at: http://dx.doi.org/10.1098/rsbl.2009.0789 PAPER IV: Opdal, A. F.; Vikebø, F. B. and Fiksen, Ø. (2010), Historical changes in spawning grounds of Northeast Arctic cod outweigh role of climatic variation for early life thermal exposure. Draft version. Full text not available in BORA. urn:isbn:978-82-308-1662-2 (print version) http://hdl.handle.net/1956/4583 The author Copyright the author. All rights reserved VDP::Mathematics and natural science: 400::Zoology and botany: 480::Marine biology: 497 Doctoral thesis 2010 ftunivbergen https://doi.org/10.1890/07-1469.110.2960/J.v41.m62110.1098/rsbl.2009.0789 2023-03-14T17:40:40Z The Northeast Arctic (NA) cod is known to undertake long southbound spawning migrations from their feeding grounds in the Barents Sea, to various spawning grounds along the Norwegian coast. Hence it’s native Norwegian name “skrei”, meaning to move or to travel. The spawned eggs and larvae subsequently drift northwards along with the prevailing currents, eventually reaching the Barents Sea as juveniles. From commercial fisheries statistics we see that these spawning grounds once spanned across nearly 2000 km of the west coast of Norway, from Finnmark in the north to Vest-Agder at the very south. Today the latitudinal range of the spawning grounds is significantly reduced, with only a marginal part of the stock spawning as far south as Møre, some 1500 km from the Barents Sea. Coarse estimates from the Institute of Marine Research suggest that around 90 - 95 % of the spawning stock spawn from Lofoten and northwards, utilizing only a third of their original expanse. Also, recent scientific surveys have found that during the last decade, the NA cod have to a great extent stopped spawning at their major traditional grounds in Vestfjorden, Lofoten, and have relocated to more northbound areas. Historically, scientists have shown little interest in the changes in spawning grounds, but due to the major impact this recent shift has had on local fishermen and landing ports, the topic currently attracts noticeable interest from fisheries scientists as well as climate scientists. The NA cod’s previous widespread spawning distribution, together with its historical and contemporary northbound shifts has spurred two major research questions addressed in this thesis. First, why does spawning take place over such a vast geographical area, implying that certain parts of the population undergo spawning migrations several thousands of kilometres further than their conspecifics? Secondly, what has caused the northbound shift in spawning grounds? From general evolutionary theory, we would expect that individuals undertaking longer ... Doctoral or Postdoctoral Thesis Arctic Arctic cod Arctic Barents Sea Finnmark Lofoten Northeast Arctic cod Vestfjorden Finnmark Skrei University of Bergen: Bergen Open Research Archive (BORA-UiB) Arctic Barents Sea Lofoten Norway Ecology 89 12 3436 3448 |