Studying the contribution of different fishing gears to the Sardinella small-scale fishery in Senegalese waters

Ousmane Diankha (1, 2) , Hervé Demarcq (3, 4) , Massal Fall (5) , Djiga Thiao (5) , Modou Thiaw (5) , Bamol Ali Sow (6, 7) , Amadou Thierno Gaye (2, 1) , Patrice Brehmer (8, 4)

1 ESP - École Supérieure Polytechnique de Dakar
2 LPAO-SF - Laboratoire de Physique de l'Atmosphère et de l'Océan Siméon Fongang
3 UMR MARBEC - MARine Biodiversity Exploitation and Conservation
4 IRD - Institut de Recherche pour le Développement
5 ISRA - Institut Sénégalais de Recherches Agricoles [Dakar]
6 UASZ - Université Assane Seck de Ziguinchor [Sénégal]
7 LOSEC - Laboratoire d'Océanographie, des sciences de l'environnement et du climat [Sénégal]
8 LEMAR - Laboratoire des Sciences de l'Environnement Marin (LEMAR)

This study investigated variations of landings of two key species, Sardinella aurita and Sardinella maderensis, in Senegalese waters over a ten-year period (2004-2013). Using generalized additive models, it was found that fishing gear played a major role in explaining differences in monthly landings for both species (51-71% deviance explained). Its effect was more significant in the southern part of Senegal. Fishing effort (number of trips) accounted only for 4-18% of variability in landings. Purse seine (PS) fishing was the most important contributor to the landings of both species. In addition, in the southern area, surrounding gillnet fishing was also important for S. maderensis. Modeling results showed that the relationship between monthly effort and landings was generally positive and leveling off, while it was dome shaped for PSs and surrounding gillnets. Thus, when estimating fishing effort indices for management in Senegal, it is necessary to account for differences in fishing gears and the non-linear relationship between fishing effort and landings.

Mots clés: Surrounding gillnet; Senegal; ACL; Effects of fishing; Generalized additive model; Sardinella aurita; Sardinella maderensis; Purse seine

Domaines: Ecosystèmes; Sciences et techniques des pêches; Biodiversité et Ecologie; Milieux et Changements globaux

Ousmane Diankha, Hervé Demarcq, Massal Fall, Djiga Thiao, Modou Thiaw, et al.. Studying the contribution of different fishing gears to the Sardinella small-scale fishery in Senegalese waters. Aquatic Living Resources, 2017, 30, pp.27. ⟨10.1051/alr/2017027⟩. ⟨hal-01928501⟩