Seascape ecology of Atlantic cod (Gadus morhua) in coastal Skagerrak: population structure, connectivity, and role in fish assemblage
Atlantic cod populations along the Norwegian Skagerrak coast consist of two known ecotypes. During the last decade, there has been a dramatic decline of larger cod and other piscivorous fish species in eastern Skagerrak. In my PhD-project, I set out to study the outer Oslo fjord seascape with a main...
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Format: | Doctoral or Postdoctoral Thesis |
Language: | English |
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Universietet i Agder
2020
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Online Access: | https://hdl.handle.net/11250/3148478 |
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Unvieristy of Agder: AURA |
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ftagderuniv |
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English |
topic |
VDP::Landbruks- og Fiskerifag: 900::Fiskerifag: 920 |
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VDP::Landbruks- og Fiskerifag: 900::Fiskerifag: 920 Synnes, Ann-Elin Seascape ecology of Atlantic cod (Gadus morhua) in coastal Skagerrak: population structure, connectivity, and role in fish assemblage |
topic_facet |
VDP::Landbruks- og Fiskerifag: 900::Fiskerifag: 920 |
description |
Atlantic cod populations along the Norwegian Skagerrak coast consist of two known ecotypes. During the last decade, there has been a dramatic decline of larger cod and other piscivorous fish species in eastern Skagerrak. In my PhD-project, I set out to study the outer Oslo fjord seascape with a main focus on the Atlantic cod (Gadus morhua) populations residing in the system, with the aim to generate fundamental knowledge on ecology, and evaluate potential for restoration of local populations. We conducted studies on genetic structuring of the two known ecotypes of cod present in this area, and combined genetic and oceanographic data to reveal potential spawning sites. Moreover, the absence of top predators gave the opportunity to investigate how the ecosystem compared to a contrasting seascape harboring a system of MPAs. First, we studied the potential for natural selection to act on a specifically designed single nucleotide polymorphism (SNP) panel used to differentiate between the two ecotypes of Atlantic cod, testing if these high-graded SNPs were unreliable for discriminating populations. We found no evidence for selection and concluded that high-graded marker panels under putative natural selection indeed represent a valid tool for identifying population structure in this species. Second, we investigated the fish assemblage in outer Oslo fjord to quantify and characterize the species present and compared the observed patterns to a protected seascape in southern Norway. We found evidence of a mesopredatory release in outer Oslo fjord, likely resulting from fishing down of the larger top predator species. Average length of cod sampled in the partially protected seascape was significantly larger than for cod caught in outer Oslo fjord. Mesopredatory fish species was in general more variable in the outer Oslo fjord seascape, and more stable in the Tvedestrand MPA. Third, we used genetic data from 0-group and 1-group cod coupled with a biophysical model of ocean drift to infer likely sources of cod recruits to ... |
format |
Doctoral or Postdoctoral Thesis |
author |
Synnes, Ann-Elin |
author_facet |
Synnes, Ann-Elin |
author_sort |
Synnes, Ann-Elin |
title |
Seascape ecology of Atlantic cod (Gadus morhua) in coastal Skagerrak: population structure, connectivity, and role in fish assemblage |
title_short |
Seascape ecology of Atlantic cod (Gadus morhua) in coastal Skagerrak: population structure, connectivity, and role in fish assemblage |
title_full |
Seascape ecology of Atlantic cod (Gadus morhua) in coastal Skagerrak: population structure, connectivity, and role in fish assemblage |
title_fullStr |
Seascape ecology of Atlantic cod (Gadus morhua) in coastal Skagerrak: population structure, connectivity, and role in fish assemblage |
title_full_unstemmed |
Seascape ecology of Atlantic cod (Gadus morhua) in coastal Skagerrak: population structure, connectivity, and role in fish assemblage |
title_sort |
seascape ecology of atlantic cod (gadus morhua) in coastal skagerrak: population structure, connectivity, and role in fish assemblage |
publisher |
Universietet i Agder |
publishDate |
2020 |
url |
https://hdl.handle.net/11250/3148478 |
genre |
atlantic cod Gadus morhua |
genre_facet |
atlantic cod Gadus morhua |
op_source |
185 |
op_relation |
Doctoral dissertations at University of Agder;no. 294 Paper I: Jorde, P. E., Synnes, A.-E., Espeland, S. H., Sodeland, M., Knutsen, H. (2018). Can we rely on selected genetic markers for population identification? Evidence from coastal Atlantic cod. Ecology and evolution, 8(24), 12547-12558. 10.1002/ece3.4648. Published version. Full-text is available in AURA as a separate file: http://hdl.handle.net/11250/2596154. Paper II: Synnes, A.E., Olsen, E.M., Jorde, P.E., Knutsen, H., Espeland, S.H., Moland, E. (2023). Contrasting management regimes indicative of a mesopredatory release in temperate coastal fish assemblages. Ecology and Evolution, 13(12), 10745, 1-14. https://doi.org/10.1002/ece3.10745. Submitted version. Full-text is available in AURA as a separate file: https://hdl.handle.net/11250/3113775. Paper III: Synnes, A.E., Huserbråten, M., Knutsen, H., Jorde, P.E., Siodeland, M., Moland, E. (2021). Local recruitment of Atlantic cod and putative source spawning areas in a coastal seascape. ICES Journal of Marine Science. 78(10), 3767-3779. https://doi.org/10.1093/icesjms/fsab226. Submitted version. Full-text is available in AURA as a separate file: https://hdl.handle.net/11250/2987500. Paper IV: Synnes, A.E., Olsen, E.M., Jorde, P.E., Knutsen, H., Moland, E. (Forthcomming). Fate of Atlantic cod (Gadus morhua) recruits assigned to two ecotypes in a Skagerrak coastal seascape. Submitted version. Full-text is not available in AURA as a separate file. Synnes, A.-E. W. (2020). Seascape ecology of Atlantic cod (Gadus morhua) in coastal Skagerrak: Population structure, connectivity, and role in fish assemblage. [Doctoral Dissertation.] Universitetet i Agder. urn:isbn:978-82-7117-996-0 urn:issn:1504-9272 https://hdl.handle.net/11250/3148478 cristin:1837244 |
op_rights |
Attribution-NonCommercial-NoDerivatives 4.0 Internasjonal http://creativecommons.org/licenses/by-nc-nd/4.0/deed.no © 2020 Ann-Elin Wårøy Synnes |
op_doi |
https://doi.org/10.1002/ece3.1074510.1093/icesjms/fsab226 |
_version_ |
1810431677162323968 |
spelling |
ftagderuniv:oai:uia.brage.unit.no:11250/3148478 2024-09-15T17:55:23+00:00 Seascape ecology of Atlantic cod (Gadus morhua) in coastal Skagerrak: population structure, connectivity, and role in fish assemblage Synnes, Ann-Elin 2020 application/pdf https://hdl.handle.net/11250/3148478 eng eng Universietet i Agder Doctoral dissertations at University of Agder;no. 294 Paper I: Jorde, P. E., Synnes, A.-E., Espeland, S. H., Sodeland, M., Knutsen, H. (2018). Can we rely on selected genetic markers for population identification? Evidence from coastal Atlantic cod. Ecology and evolution, 8(24), 12547-12558. 10.1002/ece3.4648. Published version. Full-text is available in AURA as a separate file: http://hdl.handle.net/11250/2596154. Paper II: Synnes, A.E., Olsen, E.M., Jorde, P.E., Knutsen, H., Espeland, S.H., Moland, E. (2023). Contrasting management regimes indicative of a mesopredatory release in temperate coastal fish assemblages. Ecology and Evolution, 13(12), 10745, 1-14. https://doi.org/10.1002/ece3.10745. Submitted version. Full-text is available in AURA as a separate file: https://hdl.handle.net/11250/3113775. Paper III: Synnes, A.E., Huserbråten, M., Knutsen, H., Jorde, P.E., Siodeland, M., Moland, E. (2021). Local recruitment of Atlantic cod and putative source spawning areas in a coastal seascape. ICES Journal of Marine Science. 78(10), 3767-3779. https://doi.org/10.1093/icesjms/fsab226. Submitted version. Full-text is available in AURA as a separate file: https://hdl.handle.net/11250/2987500. Paper IV: Synnes, A.E., Olsen, E.M., Jorde, P.E., Knutsen, H., Moland, E. (Forthcomming). Fate of Atlantic cod (Gadus morhua) recruits assigned to two ecotypes in a Skagerrak coastal seascape. Submitted version. Full-text is not available in AURA as a separate file. Synnes, A.-E. W. (2020). Seascape ecology of Atlantic cod (Gadus morhua) in coastal Skagerrak: Population structure, connectivity, and role in fish assemblage. [Doctoral Dissertation.] Universitetet i Agder. urn:isbn:978-82-7117-996-0 urn:issn:1504-9272 https://hdl.handle.net/11250/3148478 cristin:1837244 Attribution-NonCommercial-NoDerivatives 4.0 Internasjonal http://creativecommons.org/licenses/by-nc-nd/4.0/deed.no © 2020 Ann-Elin Wårøy Synnes 185 VDP::Landbruks- og Fiskerifag: 900::Fiskerifag: 920 Doctoral thesis 2020 ftagderuniv https://doi.org/10.1002/ece3.1074510.1093/icesjms/fsab226 2024-08-28T23:45:33Z Atlantic cod populations along the Norwegian Skagerrak coast consist of two known ecotypes. During the last decade, there has been a dramatic decline of larger cod and other piscivorous fish species in eastern Skagerrak. In my PhD-project, I set out to study the outer Oslo fjord seascape with a main focus on the Atlantic cod (Gadus morhua) populations residing in the system, with the aim to generate fundamental knowledge on ecology, and evaluate potential for restoration of local populations. We conducted studies on genetic structuring of the two known ecotypes of cod present in this area, and combined genetic and oceanographic data to reveal potential spawning sites. Moreover, the absence of top predators gave the opportunity to investigate how the ecosystem compared to a contrasting seascape harboring a system of MPAs. First, we studied the potential for natural selection to act on a specifically designed single nucleotide polymorphism (SNP) panel used to differentiate between the two ecotypes of Atlantic cod, testing if these high-graded SNPs were unreliable for discriminating populations. We found no evidence for selection and concluded that high-graded marker panels under putative natural selection indeed represent a valid tool for identifying population structure in this species. Second, we investigated the fish assemblage in outer Oslo fjord to quantify and characterize the species present and compared the observed patterns to a protected seascape in southern Norway. We found evidence of a mesopredatory release in outer Oslo fjord, likely resulting from fishing down of the larger top predator species. Average length of cod sampled in the partially protected seascape was significantly larger than for cod caught in outer Oslo fjord. Mesopredatory fish species was in general more variable in the outer Oslo fjord seascape, and more stable in the Tvedestrand MPA. Third, we used genetic data from 0-group and 1-group cod coupled with a biophysical model of ocean drift to infer likely sources of cod recruits to ... Doctoral or Postdoctoral Thesis atlantic cod Gadus morhua Unvieristy of Agder: AURA |