Effect of climate variability on decadal changes in small pelagic fisheries in the West African upwelling Ecosystem : the case of Sardinella aurita in Senegal [résumé]

• Main Authors: Thiaw, M., Faye, S., Auger, Pierre-Amaël, Brochier, Timothée, Brehmer, Patrice
• Other Authors: Unité de modélisation mathématique et informatique des systèmes complexes Bondy (UMMISCO), Université Gaston Berger de Saint-Louis Sénégal (UGB)-Université de Yaoundé I (UY1)-Institut de la francophonie pour l'informatique-Université Cadi Ayyad Marrakech (UCA)-Sorbonne Université (SU)-Institut de Recherche pour le Développement (IRD France-Nord )-Université Cheikh Anta Diop de Dakar Sénégal (UCAD), Institut de Recherche pour le Développement (IRD), Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Brehmer, Patrice (ed.), Ba, B. (ed.), Kraus, G. (ed.)
• Format: Conference Object
• Language: English
• Published: HAL CCSD 2016
• Subjects: AFRIQUE DE L'OUEST; SENEGAL; ATLANTIQUE; [SDV.SA.STP]Life Sciences [q-bio]/Agricultural sciences/Sciences and technics of fishery; [SDV.EE]Life Sciences [q-bio]/Ecology; environment; North Atlantic; North Atlantic oscillation
• Online Access: https://hal.science/hal-04372755

ICAWA : International Conference AWA, Dakar, SEN, 13-/12/2016 - 15/12/2016 In Northwest African upwelling system, the populations of Sardinella aurita show evidence of important log-term natural fluctuations in their abundance, which have implications for medium and long-term forecasting of catches. These fluctuations seem to be related, among other factor, to large-scale climatic variability, raising important scientific and economics concerns. Understanding the processes affecting recruitment/abundance is a fundamental objective of fisheries biology. Thus, this study assesses the effect of climatic variability on the abundance of S. aurita in Northwest African upwelling system. Monthly data indicating the abundance of sardinella were first estimated from commercial statistics, using Generalized Linear Model techniques over the period 1966- 2011. Abundance indices 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 times series analyses, linear models and generalized additive models. 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. The trend of the sardinella abundance was significantly correlated with the CUI, especially in autumn and spring. Interannual fluctuations of S. aurita abundance are respectively driven by the precocity and the duration of the upwelling season that is attributed to distinct migration patterns. 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, either related to migration patterns. The wide variations in sardinella biomass are caused by variations in environmental conditions, which should be ...