Chapter 14 - Neglected But Not Forgotten—Southern Africa’s Dusky Dolphins

Abstract

While it is true that there has been no systematic research project on dusky dolphins in Southern Africa, information has been collected opportunistically as a byproduct of a number of other research projects, and this chapter attempts to summarize the knowledge accumulated in the process. Despite being the local type of the species, the region has been singularly wanting in providing further information on this little dolphin. It is interesting to compare aspects of the biology of the dusky dolphin population of Southern Africa with those for the same species of Peru, as these two populations inhabit the two major coastal upwelling systems in the southern hemisphere, but genetically are highly differentiated. Despite a rather small sample from Southern Africa, there also seem to be differences in the reproductive behavior of dusky dolphins from the two regions. The calving season in Southern African waters is some four months later than that of Peru, occurring in late summer rather than spring. The different timing of the breeding seasons between the two populations may be linked to seasonal differences in biological productivity between the two regions, as shown by remote sensing of chlorophyll concentrations. In conclusion, the differences seen between the biology of dusky dolphins of Peru and in the southern Benguela may have evolved as adaptations to foraging in environments with very different variabilities and seasonal availability of prey.