Third annual boat survey of the Delta Saloum, Senegal includes more capacity building, habitat mapping and photo-identification

Third annual boat survey of the Delta Saloum, Senegal includes more capacity building, habitat mapping and photo-identification

Sousa teuszii surface in front of a fish landing and smoking site in the Delta Saloum, Senegal. Photo copyright Diana Seck, AACF/CCAHD

From March 9-29th, 2023, team members conducted the third boat-based survey of the Saloum Delta, building on previous surveys conducted in July 2021 and March-April 2022. The boat surveys are part of a wider project to understand the distribution, threats, habitat use and abundance of Sousa teuszii in the Saloum Delta. The project is funded by Fundación Loro Parque, and is hosted and implemented by the African Aquatic Conservation Fund (AACF) with support from the CCAHD.

The 2023 survey covered a total of 1650 kms of track line and resulted in a total of 29 sightings of Sousa teuszii, and thousands of photos that will be analysed and entered into the photo-identification catalogue.  Individual dolphins can be recognized by the scarring and marks on their dorsal fins, and Senegalese AACF staff member Diana Seck is using the photos collected in 2021 and 2022 to conduct a mark-recapture analysis as part of her Master’s degree course through the University of Algarve, Portugal. This technique will allow insight into individual’s movements and habitat use within the survey area and will ultimately yield a population estimate for the number of dolphins living in the Delta Saloum.

The team was also joined by Regis Kema Kema, who is working toward his PhD focusing on cetaceans in Gabon while also working to oversee cetacean research with Gabon’s National Parks Agency (ANPN).  Long days on the boat followed by evenings of data downloading, entry and processing provided plenty of opportunities for the team to exchange knowledge and experience, ranging from photography tips to the most efficient ways to archive and visualize data in GIS.

Staff from local marine protected areas also joined the survey, allowing them to participate in the research and helping to consolidate local sighting and stranding reporting networks.  Regis and local MPA staff were also able to exchange experiences related to the management of protected areas in Gabon and Senegal.

During the 2023 survey, the team also recovered one passive acoustic recorder and (re-) deployed three recorders.  These have been placed in areas where dolphin sightings have been documented both by local communities and previous surveys, and it is expected that they will provide insight into dolphin presence around the clock and in relation to tidal cycles.  For the first time the team also deployed an acoustic device from the boat while working with dolphin groups, hopefully ensuring that ‘voucher data’ is now available to confirm that any vocalisations recorded by the passive moored devices are indeed those of Sousa teuszii.


Diana and Lucy from AACF, Senegal, Demba the Senegalese boat driver, and Regis from Gabon. Photo by Gianna Minton.

Regis Kema Kema from Gabon, and Diana Seck from AACF, Senegal enter data and map the data at the end of the day. Photo by Gianna Minton.

Atlantic humpback dolphin in a typical environment in the Saloum Delta- close to shore, which can include mangrove stands and arid scrubland.

The team took thousands of photos with an aim toward expanding the photo-identification catalogue that will allow recognition of individuals over time to map their movements and habitat use and to generate an abundance estimate. Photos by Diana Seck, AACF/CCAHD.

Regis Kema Kema from the Gabon National Parks Agency and Samba Ndiaye from the Gandoule MPA in the Delta Saloum share experiences of managing marine protected areas. Photo by Lucy Keith-Diagne.

Lucy Keith-Diagne shares a CCAHD regional marine mammal ID guide with a staff member from the Palmarin Marine Protected Area.

Diana prepares a little FPOD for deployment. It will record dolphin vocalisations over the next 3 months.