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The first Nansen research survey this year has just come to an end. Twenty seven scientists on board the research vessel - Dr Fridtjof Nansen - spent the past three weeks in Northwest Africa. The scientific crew – which featured scientists and technicians from Norway, Mauritania and Senegal – carried out environmental monitoring and habitat mapping studies in the waters of Mauritania and Senegal. The researchers on board the vessel collected data, relevant information and gained knowledge that will help develop a baseline to mitigate potential impacts of future offshore oil and gas activities on the marine environment. 

During the first week of ocean exploration, the scientists discovered a large cold-water Lophelia pertusa reef with associated rich fauna, including several fish species. The reef, recorded with the use of multi-beam sonar and video transects, was situated in the vicinity of the pipeline corridor of the Grand Tortue Ahmeyim (GTA) gas field development project. For the first time, scientists documented a living reef in the boundary region of Mauritania and Senegal. Lophelia pertusa reefs occur in several locations of the Atlantic Ocean, including the southern hemisphere. They are biodiversity hotspots – both rich with life and at high risk for destruction. A physical damage might cause their immediate decline and long recovery process. For this reason, Lophelia perusa reefs are categorized by the OSPAR Convention for the Protection of the Marine Environment of the North-East Atlantic as ‘a habitat under threat and/or in decline in all the OSPAR Regions where it occurs’ and requires particular management attention. Information on distribution, ecology and conservation status of Lophelia reefs in the tropical/subtropical Atlantic is still poorly known.

During the following weeks, bottom habitat mapping revealed many more healthy coral reefs as well as deep-sea coral gardens near the pipeline corridor and in neighbouring canyons. All samples and data collected, including for sediment and organisms living on and near the sea-bottom, will be analysed and used for the preparation of the baseline report, as a reference for future environmental monitoring in this area. However, the current data on the occurrence of Lophelia reefs can already inform relevant authorities of possible measures required to protect them. 

“It is truly satisfying to see that the data generated from this research can be used by the authorities of Mauritania and Senegal to devise their own environmental management strategies allowing to mitigate the potential impacts of oil and gas activities. It is the best outcome we could have hoped for from this survey,” said Dr Tina Kutti, scientist from the Norwegian Institute of Marine Research (IMR) and the cruise leader of the expedition.

The area of the gas field development project, situated in the offshore waters of both Mauritania and Senegal, was selected as the focus area for the survey by national authorities in these countries, based on advice by local scientists that this zone may host vulnerable bottom-sea ecosystems, such as cold-water coral reefs.

The environmental monitoring survey in West Africa focused on studies of bottom-sea communities, sediment contamination and impacts on fish. The work has been achieved through a close collaboration between the scientists from the Norwegian Institute of Marine Research, the scientists from the Mauritanian Institute of Oceanographic Research and Fisheries (IMROP) and the scientists from the Oceanographic Research Centre of Dakar-Thiaroye (CRODT) of the Senegalese Institute for Agricultural Research (ISRA).

“Through capacity development, achieved by strengthening collaboration between the Norwegian and the local scientists from Mauritania and Senegal working together while onboard, the EAF-Nansen Programme can make a true difference in maintaining healthy marine ecosystems in areas of offshore industrial activities,” underlined Prof. Ketil Hylland, a lead scientist of the EAF-Nansen Program Science Plan Theme 5 - oil/gas activities and their impacts on marine ecosystems.

The strategy chosen to develop the baseline study for potential future impact of oil and gas activities in Northwest Africa is in line with the strategy developed for monitoring oil and gas impacts on bottom habitats in the North Sea region. This strategy has been integrated into Norwegian legislation and is in accordance with OSPAR recommendations.  

Fish blood and bile sampling, as well as species identification. © Ketil Hylland.

Thanks to the advanced technology of the vessel and its modern scientific equipment, the Dr Fridtjof Nansen represents a unique tool for this type of studies. A follow-up survey in the area, once the offshore gas production takes off, will provide relevant information to evaluate potential further impacts of the activity and could provide important information foe future environmental management strategies in the two countries, as applicable.

Scientific reports demonstrating the findings from this survey are now in preparation and will be presented to the relevant authorities in Mauritania and in Senegal by the end of the year.