Seasonal dynamics of growth and mortality suggest contrasting population structure and ecology for cod, pollack, and saithe in a Norwegian fjord
We study the dynamics of Atlantic cod (Gadus morhua L.), pollack (Pollachius pollachius L.), and saithe (Pollachius virens L.) in Masfjorden, a small fjord in western Norway. Annually, cohorts of pollack and cod grow in size and decline in abundance, as expected of closed populations, whereas saithe...
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2012
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ftiiasalaxenburg:oai:pure.iiasa.ac.at:10233 2023-05-15T15:27:36+02:00 Seasonal dynamics of growth and mortality suggest contrasting population structure and ecology for cod, pollack, and saithe in a Norwegian fjord Heino, M. Svasand, T. Nordeide, J.T. Ottera, H. 2012 text https://pure.iiasa.ac.at/id/eprint/10233/ https://pure.iiasa.ac.at/id/eprint/10233/1/IR-12-042.pdf en eng IR-12-042 https://pure.iiasa.ac.at/id/eprint/10233/1/IR-12-042.pdf Heino, M. <https://pure.iiasa.ac.at/view/iiasa/122.html> orcid:0000-0003-2928-3940 , Svasand, T., Nordeide, J.T., & Ottera, H. (2012). Seasonal dynamics of growth and mortality suggest contrasting population structure and ecology for cod, pollack, and saithe in a Norwegian fjord. IIASA Interim Report. IIASA, Laxenburg, Austria: IR-12-042 Monograph NonPeerReviewed 2012 ftiiasalaxenburg 2023-04-07T14:49:41Z We study the dynamics of Atlantic cod (Gadus morhua L.), pollack (Pollachius pollachius L.), and saithe (Pollachius virens L.) in Masfjorden, a small fjord in western Norway. Annually, cohorts of pollack and cod grow in size and decline in abundance, as expected of closed populations, whereas saithe virtually disappear before maturity. Seasonally, in contrast, the dynamics of cod and pollack differ. Pollack shows a regular growth pattern, with most of the growth taking place in summer. Its abundance-at-age shows strong seasonal variations, with a marked increase from spring to summer followed by a decline through autumn and winter. These patterns relate partly to seasonal changes in depth distribution and catchability. Combined with the observation that spawning-stage pollack are abundant in spring, we interpret these patterns to suggest that pollack in Masfjorden represent a dynamically independent unit. Seasonal changes in abundance are less marked for cod, and seasonal changes in depth distribution seem insignificant. However, cod shows an unusual pattern in length-at-age, with no apparent growth in summer and fast growth in autumn. These patterns suggest that the population structure of cod may be more open than that of pollack and may involve mixing of more than one population component. Book atlantic cod Gadus morhua IIASA PURE (International Institute of Applied Systems Analysis: PUblications REpository) Norway |
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Open Polar |
collection |
IIASA PURE (International Institute of Applied Systems Analysis: PUblications REpository) |
op_collection_id |
ftiiasalaxenburg |
language |
English |
description |
We study the dynamics of Atlantic cod (Gadus morhua L.), pollack (Pollachius pollachius L.), and saithe (Pollachius virens L.) in Masfjorden, a small fjord in western Norway. Annually, cohorts of pollack and cod grow in size and decline in abundance, as expected of closed populations, whereas saithe virtually disappear before maturity. Seasonally, in contrast, the dynamics of cod and pollack differ. Pollack shows a regular growth pattern, with most of the growth taking place in summer. Its abundance-at-age shows strong seasonal variations, with a marked increase from spring to summer followed by a decline through autumn and winter. These patterns relate partly to seasonal changes in depth distribution and catchability. Combined with the observation that spawning-stage pollack are abundant in spring, we interpret these patterns to suggest that pollack in Masfjorden represent a dynamically independent unit. Seasonal changes in abundance are less marked for cod, and seasonal changes in depth distribution seem insignificant. However, cod shows an unusual pattern in length-at-age, with no apparent growth in summer and fast growth in autumn. These patterns suggest that the population structure of cod may be more open than that of pollack and may involve mixing of more than one population component. |
format |
Book |
author |
Heino, M. Svasand, T. Nordeide, J.T. Ottera, H. |
spellingShingle |
Heino, M. Svasand, T. Nordeide, J.T. Ottera, H. Seasonal dynamics of growth and mortality suggest contrasting population structure and ecology for cod, pollack, and saithe in a Norwegian fjord |
author_facet |
Heino, M. Svasand, T. Nordeide, J.T. Ottera, H. |
author_sort |
Heino, M. |
title |
Seasonal dynamics of growth and mortality suggest contrasting population structure and ecology for cod, pollack, and saithe in a Norwegian fjord |
title_short |
Seasonal dynamics of growth and mortality suggest contrasting population structure and ecology for cod, pollack, and saithe in a Norwegian fjord |
title_full |
Seasonal dynamics of growth and mortality suggest contrasting population structure and ecology for cod, pollack, and saithe in a Norwegian fjord |
title_fullStr |
Seasonal dynamics of growth and mortality suggest contrasting population structure and ecology for cod, pollack, and saithe in a Norwegian fjord |
title_full_unstemmed |
Seasonal dynamics of growth and mortality suggest contrasting population structure and ecology for cod, pollack, and saithe in a Norwegian fjord |
title_sort |
seasonal dynamics of growth and mortality suggest contrasting population structure and ecology for cod, pollack, and saithe in a norwegian fjord |
publisher |
IR-12-042 |
publishDate |
2012 |
url |
https://pure.iiasa.ac.at/id/eprint/10233/ https://pure.iiasa.ac.at/id/eprint/10233/1/IR-12-042.pdf |
geographic |
Norway |
geographic_facet |
Norway |
genre |
atlantic cod Gadus morhua |
genre_facet |
atlantic cod Gadus morhua |
op_relation |
https://pure.iiasa.ac.at/id/eprint/10233/1/IR-12-042.pdf Heino, M. <https://pure.iiasa.ac.at/view/iiasa/122.html> orcid:0000-0003-2928-3940 , Svasand, T., Nordeide, J.T., & Ottera, H. (2012). Seasonal dynamics of growth and mortality suggest contrasting population structure and ecology for cod, pollack, and saithe in a Norwegian fjord. IIASA Interim Report. IIASA, Laxenburg, Austria: IR-12-042 |
_version_ |
1766358027491868672 |