Dolphins in the coastal area of Guiné Bissau

This paper describes the results of a study conducted in the Archipelago of Bijagos in Guinea Bissau. Bottle-nosed dolphins were observed 13 times and Atlantic hump-backed dolphins 56 times. The humpbacked dolphin was mainly observed in the more sheltered parts of the area, in turbid as well as in clear water. in Guine Bissau, bottle-nosed dolphins seem to avoid the more sheltered areas. The observed distribution of the two species here suggests a certain degree of spatial separation. The occurrence of both species as a function of the tidal cycle. Most sightings were made during low tide, when fish (the food of the dolphins) is concentrated in the deeper parts of the area. Because we never saw dolphins outside the gullies and creeks, the higher proportion of sightings during low tide probably is the result of the increased feeding activity during this period. The largest Sousa group numbered at least 15. The average number was 4.1-4.5 dolphins per sighting.