The most frequented sites are not necessarily the most studied. In Senegal, towns and villages exist along the 300 kilometres of the Casamance River. And yet little is known about the varied fauna that lives in these waters, despite there being many emblematic species including dolphins, otters, Nile crocodiles and the greatly endangered manatee.
In July 2018, a team comprised of four French and six Senegalese travelled up the first 200 kilometres of the Casamance to collect water samples from various locations: in the middle of the estuary, in side channels and in the heart of the mangrove.
Among the dozens of species of fish, as well as mammals, amphibians and birds thus identified, traces of manatee DNA were found in an area where the species was thought to have disappeared.
The mission enabled us to identify a great diversity of fish and observe their distribution, with widely differing communities observed in different zones. Among the dozens of species of fish, as well as mammals, amphibians and birds thus identified, traces of manatee DNA were found in an area where the species was thought to have disappeared. Lastly, one of the aims of the mission was to test the method in a particularly vast site, despite the small team and meagre means. The gamble paid off !
© Jean-Baptiste Decotte
