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

• Published in: Fisheries Oceanography
• Main Authors: Thiaw, Modou, Auger, Pierre-Amael, Ngom, Fambaye, Brochier, Timothee, Faye, Saliou, Diankha, Ousmane, Brehmer, Patrice
• Other Authors: Institut Sénégalais de Recherches Agricoles Dakar (ISRA), Pontificia Universidad Católica de Valparaíso (PUCV), 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 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), Institut de Recherche pour le Développement (IRD), Unité de modélisation mathématique et informatique des systèmes complexes Bondy (UMMISCO), Institut de Recherche pour le Développement (IRD France-Nord )-Institut de la francophonie pour l'informatique-Université Cheikh Anta Diop Dakar, Sénégal (UCAD)-Université Gaston Bergé (Saint-Louis, Sénégal)-Université Cadi Ayyad Marrakech (UCA)-Université de Yaoundé I-Sorbonne Université (SU), Laboratoire de Physique de l'Atmosphère et de l'Océan Siméon Fongang (LPAO-SF), École Supérieure Polytechnique de Dakar (ESP), Université Cheikh Anta Diop Dakar, Sénégal (UCAD)-Université Cheikh Anta Diop Dakar, Sénégal (UCAD), European Project: 603521,EC:FP7:ENV,FP7-ENV-2013-two-stage,PREFACE(2013)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2017
• Subjects: small-scale; small-scale fisheries; upwelling areas; small pelagic; eastern atlantic; dynamics; ACL; Oceanography; Climatic change; epinephelus-aeneus; generalized additive-models; octopus-vulgaris; recruitment success; regime shifts; round sardinella; Sardinella aurita; Sardinella maderensis; [SDE.BE]Environmental Sciences/Biodiversity and Ecology; North Atlantic; North Atlantic oscillation
• Online Access: https://hal.archives-ouvertes.fr/hal-02613247; https://hal.archives-ouvertes.fr/hal-02613247/document; https://hal.archives-ouvertes.fr/hal-02613247/file/Thiaw_etal_FO_2017.pdf; https://doi.org/10.1111/fog.12218

WOS:000407178900006 International audience 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 Nino 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 4years 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.