A hypothesis of a redistribution of North Atlantic swordfish based on changing ocean conditions
Conflicting trends in indices of abundance for North Atlantic swordfish starting in the mid-to late 1990s, in the form of fleet specific catch-per-unit-effort (CPUE), suggest the possibility of a spatial shift in abundance to follow areas of preferred temperature. The observed changes in the directi...
Published in: | Deep Sea Research Part II: Topical Studies in Oceanography |
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Online Access: | http://hdl.handle.net/10508/11117 https://doi.org/10.1016/j.dsr2.2016.08.002 |
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ftieo:oai:repositorio.ieo.es:10508/11117 2023-05-15T17:30:11+02:00 A hypothesis of a redistribution of North Atlantic swordfish based on changing ocean conditions Schirripa, M.J. Abascal, F.J. (Francisco Javier) Andrushchenko, I. (Irene) Díaz, G. Mejuto-García, J. (Jaime) Ortiz, M. Santos, M.N. (Miguel Neves) Walter, J. 2017 http://hdl.handle.net/10508/11117 https://doi.org/10.1016/j.dsr2.2016.08.002 eng eng Centro Oceanográfico de Canarias 0967-0645 http://hdl.handle.net/10508/11117 Deep Sea Research Part II: Topical Studies in Oceanography, 140. 2017: 139-150 doi:10.1016/j.dsr2.2016.08.002 Atribución-NoComercial-SinDerivadas 3.0 España http://creativecommons.org/licenses/by-nc-nd/3.0/es/ open access CC-BY-NC-ND Abundance indices Environmental factors Stock distribution Swordfish fish deep water marine fisheries fisheries research research article AM 2017 ftieo https://doi.org/10.1016/j.dsr2.2016.08.002 2022-12-07T00:50:10Z Conflicting trends in indices of abundance for North Atlantic swordfish starting in the mid-to late 1990s, in the form of fleet specific catch-per-unit-effort (CPUE), suggest the possibility of a spatial shift in abundance to follow areas of preferred temperature. The observed changes in the direction of the CPUEs correspond with changes in trends in the summer Atlantic Multidecadal Oscillation (AMO), a long term mode of variability of North Atlantic sea surface temperature. To test the hypothesis of a relation between the CPUE and the AMO, the CPUEs were made spatially explicit by re-estimating using an “areas-as-fleets” approach. These new CPUEs were then used to create alternative stock histories. The residuals of the fit were then regressed against the summer AMO. Significant, and opposite, relations were found in the regressions between eastern and western Atlantic areas. When the AMO was in a warm phase, the CPUEs in the western (eastern) areas were higher (lower) than predicted by the assessment model fit. Given the observed temperature tolerance limits of swordfish, it is possible that either their preferred habitat, prey species, or both have shifted spatial distributions resulting in conflicting CPUE indices. Because the available CPUE time series only overlaps with one change in the sign of the AMO (~1995), it is not clear whether this is a directional or cyclical trend. Given the relatively localized nature of many of the fishing fleets, and the difficulty of separating fleet effects from changes in oceanography we feel that it is critical to create CPUE indices by combining data across similar fleets that fish in similar areas. This approach allowed us to evaluate area-specific catch rates which provided the power to detect basin-wide responses to changing oceanography, a critical step for providing robust management advice in a changing climate. Article in Journal/Newspaper North Atlantic Instituto Español de Oceanografía: e-IEO Deep Sea Research Part II: Topical Studies in Oceanography 140 139 150 |
institution |
Open Polar |
collection |
Instituto Español de Oceanografía: e-IEO |
op_collection_id |
ftieo |
language |
English |
topic |
Abundance indices Environmental factors Stock distribution Swordfish fish deep water marine fisheries fisheries research |
spellingShingle |
Abundance indices Environmental factors Stock distribution Swordfish fish deep water marine fisheries fisheries research Schirripa, M.J. Abascal, F.J. (Francisco Javier) Andrushchenko, I. (Irene) Díaz, G. Mejuto-García, J. (Jaime) Ortiz, M. Santos, M.N. (Miguel Neves) Walter, J. A hypothesis of a redistribution of North Atlantic swordfish based on changing ocean conditions |
topic_facet |
Abundance indices Environmental factors Stock distribution Swordfish fish deep water marine fisheries fisheries research |
description |
Conflicting trends in indices of abundance for North Atlantic swordfish starting in the mid-to late 1990s, in the form of fleet specific catch-per-unit-effort (CPUE), suggest the possibility of a spatial shift in abundance to follow areas of preferred temperature. The observed changes in the direction of the CPUEs correspond with changes in trends in the summer Atlantic Multidecadal Oscillation (AMO), a long term mode of variability of North Atlantic sea surface temperature. To test the hypothesis of a relation between the CPUE and the AMO, the CPUEs were made spatially explicit by re-estimating using an “areas-as-fleets” approach. These new CPUEs were then used to create alternative stock histories. The residuals of the fit were then regressed against the summer AMO. Significant, and opposite, relations were found in the regressions between eastern and western Atlantic areas. When the AMO was in a warm phase, the CPUEs in the western (eastern) areas were higher (lower) than predicted by the assessment model fit. Given the observed temperature tolerance limits of swordfish, it is possible that either their preferred habitat, prey species, or both have shifted spatial distributions resulting in conflicting CPUE indices. Because the available CPUE time series only overlaps with one change in the sign of the AMO (~1995), it is not clear whether this is a directional or cyclical trend. Given the relatively localized nature of many of the fishing fleets, and the difficulty of separating fleet effects from changes in oceanography we feel that it is critical to create CPUE indices by combining data across similar fleets that fish in similar areas. This approach allowed us to evaluate area-specific catch rates which provided the power to detect basin-wide responses to changing oceanography, a critical step for providing robust management advice in a changing climate. |
format |
Article in Journal/Newspaper |
author |
Schirripa, M.J. Abascal, F.J. (Francisco Javier) Andrushchenko, I. (Irene) Díaz, G. Mejuto-García, J. (Jaime) Ortiz, M. Santos, M.N. (Miguel Neves) Walter, J. |
author_facet |
Schirripa, M.J. Abascal, F.J. (Francisco Javier) Andrushchenko, I. (Irene) Díaz, G. Mejuto-García, J. (Jaime) Ortiz, M. Santos, M.N. (Miguel Neves) Walter, J. |
author_sort |
Schirripa, M.J. |
title |
A hypothesis of a redistribution of North Atlantic swordfish based on changing ocean conditions |
title_short |
A hypothesis of a redistribution of North Atlantic swordfish based on changing ocean conditions |
title_full |
A hypothesis of a redistribution of North Atlantic swordfish based on changing ocean conditions |
title_fullStr |
A hypothesis of a redistribution of North Atlantic swordfish based on changing ocean conditions |
title_full_unstemmed |
A hypothesis of a redistribution of North Atlantic swordfish based on changing ocean conditions |
title_sort |
hypothesis of a redistribution of north atlantic swordfish based on changing ocean conditions |
publisher |
Centro Oceanográfico de Canarias |
publishDate |
2017 |
url |
http://hdl.handle.net/10508/11117 https://doi.org/10.1016/j.dsr2.2016.08.002 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_relation |
0967-0645 http://hdl.handle.net/10508/11117 Deep Sea Research Part II: Topical Studies in Oceanography, 140. 2017: 139-150 doi:10.1016/j.dsr2.2016.08.002 |
op_rights |
Atribución-NoComercial-SinDerivadas 3.0 España http://creativecommons.org/licenses/by-nc-nd/3.0/es/ open access |
op_rightsnorm |
CC-BY-NC-ND |
op_doi |
https://doi.org/10.1016/j.dsr2.2016.08.002 |
container_title |
Deep Sea Research Part II: Topical Studies in Oceanography |
container_volume |
140 |
container_start_page |
139 |
op_container_end_page |
150 |
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1766126017558085632 |