Conservation and management of humpback dolphins: the South African perspective

Population biology and socio-ecology of Indo-Pacific humpback dolphins Sous a chinensis were investigated during a 3-year study period in the Algoa Bay region, South Africa. The dolphins inhabit a narrow strip of coastal water s, mostly less than 15 m deep. Groups are small (mean = 7 animals) and thei r daily activities concentrate around shallow rocky reefs-the primary feedi ng grounds. Dependence on these restricted, shallow-water habitats is evide nt throughout the year. Site fidelity is generally weak and is subject to s easonal migration, although female site fidelity seems to be related to rep roductive stage. Births occur predominantly in summer. The social system is highly fluid, structured to some degree by sex and age,'mate-searching' be haviour being the most likely male reproductive strategy. The dolphins inha biting Algoa Bay are part of a substantially larger population that uses a considerable length of the coastal zone. Estimated population parameters ar e generally low, as are modelled population growth rates, and an increase i n the population size seems unlikely. Humpback dolphins appear to be vulner able to negative environmental pressure and the alteration/destruction of i nshore habitats is probably among the greatest threats to them. Conservatio n of this species should be given high priority and be seen as an important part of integrated coastal zone management. Establishment of multiple-use management areas with controlled ecotourism and several priority sites decl ared as strict reserves seems to be the most effective conservation approac h. In order to be successful, conservation and management policies need to recognize the needs and lifestyles of the local inhabitants.