Wintering seabirds in West Africa: foraging hotspots off Western Sahara and Mauritania driven by upwelling and fisheries

Cold-water upwelling supports abundant and diverse faunas. Upwelling off Mauritania has been highlighted as being important for seabirds, but very few systematic offshore surveys have been conducted in that region. Mauritanian waters are increasingly targeted by commercial fisheries along the shelf break and, with the likelihood of future exploitation of mineral oils on the continental shelf, the absence of information on seabirds is worrying. This paper describes the distribution of wintering seabirds in the context of fisheries and hydrography. The avifauna was dominated by surface-feeding and shallow plunge-diving, often planktivorous, seabirds, originating from West Palaearctic breeding grounds (Arctic, subarctic and temperate zones). Many seabirds were associated with fishing trawlers around the shelf break, but the fleets were more evenly distributed than the birds, with certain hydrographical parameters influencing or overruling the attraction of trawlers by seabirds. The results support the belief that West African waters are of prime importance for seabirds.