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 http://hdl.handle.net/10261/324628 https://doi.org/10.1016/j.dsr2.2016.08.002 |
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ftcsic:oai:digital.csic.es:10261/324628 2024-02-11T10:06:14+01:00 A hypothesis of a redistribution of North Atlantic swordfish based on changing ocean conditions Schirripa, M.J. Abascal, Francisco Javier Andrushchenko, Irene Díaz, G. Mejuto-García, Jaime Ortiz, M. Santos, Miguel Neves Walter, J. 2017 http://hdl.handle.net/10508/11117 http://hdl.handle.net/10261/324628 https://doi.org/10.1016/j.dsr2.2016.08.002 en eng Centro Oceanográfico de Canarias AM Deep Sea Research Part II: Topical Studies in Oceanography, 140. 2017: 139-150 0967-0645 http://hdl.handle.net/10508/11117 http://hdl.handle.net/10261/324628 doi:10.1016/j.dsr2.2016.08.002 open Pesquerías Abundance indices Centro Oceanográfico de Canarias Environmental factors Stock distribution Swordfish fish deep water marine fisheries fisheries research research article 2017 ftcsic https://doi.org/10.1016/j.dsr2.2016.08.002 2024-01-16T11:47:36Z 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. SI Article in Journal/Newspaper North Atlantic Digital.CSIC (Spanish National Research Council) Deep Sea Research Part II: Topical Studies in Oceanography 140 139 150 |
institution |
Open Polar |
collection |
Digital.CSIC (Spanish National Research Council) |
op_collection_id |
ftcsic |
language |
English |
topic |
Pesquerías Abundance indices Centro Oceanográfico de Canarias Environmental factors Stock distribution Swordfish fish deep water marine fisheries fisheries research |
spellingShingle |
Pesquerías Abundance indices Centro Oceanográfico de Canarias Environmental factors Stock distribution Swordfish fish deep water marine fisheries fisheries research Schirripa, M.J. Abascal, Francisco Javier Andrushchenko, Irene Díaz, G. Mejuto-García, Jaime Ortiz, M. Santos, Miguel Neves Walter, J. A hypothesis of a redistribution of North Atlantic swordfish based on changing ocean conditions |
topic_facet |
Pesquerías Abundance indices Centro Oceanográfico de Canarias 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. SI |
format |
Article in Journal/Newspaper |
author |
Schirripa, M.J. Abascal, Francisco Javier Andrushchenko, Irene Díaz, G. Mejuto-García, Jaime Ortiz, M. Santos, Miguel Neves Walter, J. |
author_facet |
Schirripa, M.J. Abascal, Francisco Javier Andrushchenko, Irene Díaz, G. Mejuto-García, Jaime Ortiz, M. Santos, 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 |
publishDate |
2017 |
url |
http://hdl.handle.net/10508/11117 http://hdl.handle.net/10261/324628 https://doi.org/10.1016/j.dsr2.2016.08.002 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_relation |
Centro Oceanográfico de Canarias AM Deep Sea Research Part II: Topical Studies in Oceanography, 140. 2017: 139-150 0967-0645 http://hdl.handle.net/10508/11117 http://hdl.handle.net/10261/324628 doi:10.1016/j.dsr2.2016.08.002 |
op_rights |
open |
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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1790603801056509952 |