Effect of environmental conditions on the seasonal and inter-annual variability of small pelagic fish abundance off North-West Africa : the case of both Senegalese sardinella
The objective of this study was to assess the effect of environmental variations on the abundance of Sardinella aurita and Sardinella maderensis in Senegalese waters in the upwelling system. Monthly data indicating the abundance of sardinella were first estimated from commercial statistics, using Ge...
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ftird:oai:ird.fr:fdi:010070678 2023-05-15T17:35:30+02:00 Effect of environmental conditions on the seasonal and inter-annual variability of small pelagic fish abundance off North-West Africa : the case of both Senegalese sardinella Thiaw, M. Auger, Pierre-Amaël Ngom, F. Brochier, Timothée Faye, S. Diankha, O. Brehmer, Patrice SENEGAL ATLANTIQUE 2017 http://www.documentation.ird.fr/hor/fdi:010070678 EN eng http://www.documentation.ird.fr/hor/fdi:010070678 oai:ird.fr:fdi:010070678 Thiaw M., Auger Pierre-Amaël, Ngom F., Brochier Timothée, Faye S., Diankha O., Brehmer Patrice. Effect of environmental conditions on the seasonal and inter-annual variability of small pelagic fish abundance off North-West Africa : the case of both Senegalese sardinella. Fisheries Oceanography, 2017, 26 (5), p. 583-601. text 2017 ftird 2020-08-21T06:50:41Z The objective of this study was to assess the effect of environmental variations on the abundance of Sardinella aurita and Sardinella maderensis in Senegalese waters in the upwelling system. Monthly data indicating the abundance of sardinella were first estimated from commercial statistics, using Generalized Linear Model from 1966 to 2011. Abundance indices (AIs) were then compared with environmental indices, at the local scale, a Coastal Upwelling Index (CUI) and a coastal Sea Surface Temperature (SST) index, and on a large scale, the North Atlantic Oscillation (NAO), the Atlantic Multidecadal Oscillation (AMO) and the Multivariate El Niño Southern Oscillation Index (MEI), using correlations and times series analyses. The results showed that the abundance of sardinella is determined by a strong seasonal pattern and inter-annual fluctuations. The abundance of S. aurita peaked in spring and in autumn, whereas that of S. maderensis peaked in the warm season (July-September). The trend of the sardinella abundance was significantly correlated with the CUI, especially in autumn and spring. Interannual fluctuations of S. maderensis and S. aurita abundance are, respectively, driven by the precocity and the duration of the upwelling season that is attributed to distinct migration patterns. Both sardinella species also respond with a delay of around 4 years to the winter NAO index and the autumn CUI, and the AMO index, respectively, both related to migration patterns. The wide variations in sardinella biomass are caused by variations in environmental conditions, which should be considered in the implementation of an ecosystem-based approach in sardinella stocks management. Text North Atlantic North Atlantic oscillation IRD (Institute de recherche pour le développement): Horizon |
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Open Polar |
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IRD (Institute de recherche pour le développement): Horizon |
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ftird |
language |
English |
description |
The objective of this study was to assess the effect of environmental variations on the abundance of Sardinella aurita and Sardinella maderensis in Senegalese waters in the upwelling system. Monthly data indicating the abundance of sardinella were first estimated from commercial statistics, using Generalized Linear Model from 1966 to 2011. Abundance indices (AIs) were then compared with environmental indices, at the local scale, a Coastal Upwelling Index (CUI) and a coastal Sea Surface Temperature (SST) index, and on a large scale, the North Atlantic Oscillation (NAO), the Atlantic Multidecadal Oscillation (AMO) and the Multivariate El Niño Southern Oscillation Index (MEI), using correlations and times series analyses. The results showed that the abundance of sardinella is determined by a strong seasonal pattern and inter-annual fluctuations. The abundance of S. aurita peaked in spring and in autumn, whereas that of S. maderensis peaked in the warm season (July-September). The trend of the sardinella abundance was significantly correlated with the CUI, especially in autumn and spring. Interannual fluctuations of S. maderensis and S. aurita abundance are, respectively, driven by the precocity and the duration of the upwelling season that is attributed to distinct migration patterns. Both sardinella species also respond with a delay of around 4 years to the winter NAO index and the autumn CUI, and the AMO index, respectively, both related to migration patterns. The wide variations in sardinella biomass are caused by variations in environmental conditions, which should be considered in the implementation of an ecosystem-based approach in sardinella stocks management. |
format |
Text |
author |
Thiaw, M. Auger, Pierre-Amaël Ngom, F. Brochier, Timothée Faye, S. Diankha, O. Brehmer, Patrice |
spellingShingle |
Thiaw, M. Auger, Pierre-Amaël Ngom, F. Brochier, Timothée Faye, S. Diankha, O. Brehmer, Patrice Effect of environmental conditions on the seasonal and inter-annual variability of small pelagic fish abundance off North-West Africa : the case of both Senegalese sardinella |
author_facet |
Thiaw, M. Auger, Pierre-Amaël Ngom, F. Brochier, Timothée Faye, S. Diankha, O. Brehmer, Patrice |
author_sort |
Thiaw, M. |
title |
Effect of environmental conditions on the seasonal and inter-annual variability of small pelagic fish abundance off North-West Africa : the case of both Senegalese sardinella |
title_short |
Effect of environmental conditions on the seasonal and inter-annual variability of small pelagic fish abundance off North-West Africa : the case of both Senegalese sardinella |
title_full |
Effect of environmental conditions on the seasonal and inter-annual variability of small pelagic fish abundance off North-West Africa : the case of both Senegalese sardinella |
title_fullStr |
Effect of environmental conditions on the seasonal and inter-annual variability of small pelagic fish abundance off North-West Africa : the case of both Senegalese sardinella |
title_full_unstemmed |
Effect of environmental conditions on the seasonal and inter-annual variability of small pelagic fish abundance off North-West Africa : the case of both Senegalese sardinella |
title_sort |
effect of environmental conditions on the seasonal and inter-annual variability of small pelagic fish abundance off north-west africa : the case of both senegalese sardinella |
publishDate |
2017 |
url |
http://www.documentation.ird.fr/hor/fdi:010070678 |
op_coverage |
SENEGAL ATLANTIQUE |
genre |
North Atlantic North Atlantic oscillation |
genre_facet |
North Atlantic North Atlantic oscillation |
op_relation |
http://www.documentation.ird.fr/hor/fdi:010070678 oai:ird.fr:fdi:010070678 Thiaw M., Auger Pierre-Amaël, Ngom F., Brochier Timothée, Faye S., Diankha O., Brehmer Patrice. Effect of environmental conditions on the seasonal and inter-annual variability of small pelagic fish abundance off North-West Africa : the case of both Senegalese sardinella. Fisheries Oceanography, 2017, 26 (5), p. 583-601. |
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