Seabird distribution and oceanic upwelling off northwest Africa

Large numbers of seabirds from northern Europe, including the UK, winter in a major zone of upwelling off northwest Africa. This area also attracts seabirds on migration to and from wintering areas farther south, as well as immature seabirds which are too young to breed. In spring 2003, the research ship R.V. Meteor visited this upwelling zone off Mauritania. The factors affecting seabird distribution in the region were assessed by comparing observational data on seabirds with a unique combination of other data from the study area. Fish, zooplankton and phytoplankton are concentrated along the shelf edge and upper slope where relatively cool, nutrient-rich, upwelled waters are brought to the surface, and the highest concentrations of seabirds are also found here. Although upwelling, and the associated concentration of food, appears to be the key control on seabird distribution, this pattern is complicated by human fishing activities, which are also concentrated around the shelf edge.