Back on the Boat in the Saloum Delta!

Back on the Boat in the Saloum Delta!

By Diana Seck, AACF

In February, 2025 CCAHD partner, the African Aquatic Conservation Fund (AACF) organised the fifth annual boat survey campaign for the study of Atlantic humpback dolphins (Sousa teuszii) in the Saloum Delta. For 18 days, the team navigated transects in the waters of the Delta to collect essential data on the population of this Critically Endangered species.  Using the CCAHD protocol for boat-based research, we spent a total of 132 hours in the mangrove channels of Delta Saloum, of whcih 83.5 hours were spent searching ‘on effort’ and the rest of the time was spent working with animals or navigating at speed to and from the start of transects. The total distance travelled was 1,542.6 km, with 995.7 km travelled on effort. The team comprised between 5 and 7 people each day, including the core AACF team, an intern, and a doctoral student from the University of St Andrews. We also welcomed marine protected area and national park staff, as well as a German television crew who came to document our work, thus helping to raise awareness of the critical conservation status of Sousa teuszii.

During the survey, we recorded a total of 17 dolphin sightings throughout the Delta. This data is crucial for monitoring the evolution of the population and identifying possible changes in their distribution. As in previous years, photo-identification was a key tool, and we took thousands of photos to assist with the identification and recognition of individual dolphins and to assess their habitat use and ranging patterns. We also strengthened our collaboration with staff from the Delta’s Marine Protected Areas (MPAs) and the Saloum Delta National Park, who play an essential role in protecting critical habitats for Sousa teuszii. Through individual meetings and hosting staff on the research boat, we were able to exchange valuable information on the presence of dolphins, anthropogenic pressures and management measures to reduce the threats to the species.

During the survey the team also recovered 2 bottom-mounted recorders (2 SoundTraps and 1 FPod) at strategic locations, in coordination with the managers of the MPAs and the Delta National Park. These recorders will enable us to analyse the dolphins’ communication and assess their activity in areas where direct observations are limited. Recordings were also made during dolphin encounters to build up a library of ‘voucher’ recordings that can be used in the development of a species classifier for Atlantic humpback dolphins.  The data collected is now being analyzed by the University of St. Andrews in the context of a regional collaboration on for passive acoustic monitoring of coastal marine mammals. The German television team captured footage of these operations, highlighting the challenges and methods used to protect this critically endangered species.

The AACF and CCAHD team is deeply grateful to the Loro Parque Foundation and the Hurtigruten Foundation for making this survey possible.