Vulnerable wildlife concentrations at the Mauritanian Shelf - Atlas of area sensitivity to surface pollutants. NIOZ Report 2022-04 Version 7

Maritime transport associated with the Grand Tortue Ahmeyim (GTA) gas development project will increase risks for marine wildlife (seabirds and cetaeceans) of the existing threat for accidental spills by international maritime transport, or condensate spills or leakages due to for example ruptures of the wet gas pipeline as a result from fishing activities, accidents, or sabotage.

When an accidental spill occurs, this vulnerability atlas will provide decision makers with easy to digest information on particularly sensitive area, enabling them to see, at a glance, and even before anything happened, when and where sea areas are at risk and where to prioritise clean-up/containment efforts in a crisis situation to protect marine wildlife and fishery resources.

The vulnerability of seabirds to oil (or hydrocarbon) pollution in Mauritania was assessed by parameterising an Oil Vulnerability Index (OVI), used in combination with area specific spatial information on the distribution and density of marine birds (estimates of relative abundance based on state of the art, effort-corrected survey data). The resulting maps predict which areas are most at risk from hydrocarbon spills when they occur.

Traditionally, vulnerability atlases for hydrocarbon pollution are based solely on (sensitive) seabird abundance data, while the presence and abundance of other megafauna is often put aside. Given the global importance of the Mauritanian slope and shelf area, sightings of cetaceans are added as exact plots, to integrate data and to highlight particular biodiversity hotspot areas.