West Africa's Atlantic humpback dolphin (Sousa teuszii): Endemic, enigmatic and soon endangered?

Abstract

Atlantic humpback dolphins (Sousa teuszii) are endemic to nearshore West African waters between Western Sahara and Angola. They are considered Vulnerable by the International Union for Conservation of Nature based on restricted geographic range, low abundance and apparent decline in recent decades. We review the human activities most likely to affect the species and consider appropriate conservation actions. Bycatch (incidental capture) in gillnets is the greatest immediate threat. Deaths from entanglement have been documented in Mauritania, Senegal, Guinea-Bissau, Guinea and the Republic of the Congo. In Namibe Province, Angola, 4.8 artisanal fishing boats and two gillnets per km were observed in some areas within 1 km of the coast and gillnets are deployed regularly inside bays used by dolphins. Other concerns include the 'marine bushmeat'- trade, habitat loss/degradation, overfishing, marine pollution, anthropogenic sound and climate change. Conservation challenges include a paucity of scientific data on the species, and widespread human poverty within most range states, resulting in high dependence on artisanal fisheries. Recommended conservation and research priorities include: (1) distribution and abundance surveys in known and potential range states, (2) bycatch monitoring programmes, (3) education/awareness schemes, and (4) protection of core areas via reduction/elimination of nearshore gillnetting.