The cetaceans of Ghana, a validated faunal checklist

Abstract

The cetaccans of Ghana and the Gulf of Guinea have, until recently, remained unstudied. Periodical monitoring of artisanal fisheries for bycatches in seven Ghanaian artisanal fishing ports and landing sites over 1996-2004 has provided photographic and specimen evidence to validate occurrence of 18 species (17 odontocetes, 1 mysticcete) in a tropical, predominantly pelagic cetaccan fauna. At least nine species and subspecies had not previously been documented for Ghana (with asterisk), and four species are authenticated for the first time in the Gulf of Guinea (double asterisk), i.e., Tursiops truncates, Stenella clymene, S. longirostris longirostris*, S. altenuata, S. frontalis, Delphinus capensis capensis*, Lagenodelphis hosei, steno bredanensis, Grampus grisceus, Peponocephala electra*, Feresa alternuata**, Globicephala macronhynchus, Orcinus orca*, Pseudorca crassidens*, Kogia sima**, Physter macrocephalus*, Ziphius cavirostris** and megaptera movaeangliae”. Also, the limited published information on distribution, natural history and conservation status is critically reviewed for each taxon. Indications are that most species encountered off Ghana may be widely distributed in the Gulf of Guinea, most notably the long-beaked common dolphin. The vulnerable Atlantic humpback dolphin, Sousa teuszil, remains unreacorded in Ghana and neighbouring nations despite apparently suitable coastal habitat. It is suggested that localized extinction may be blamed, possibly the result of accumulative bycatches and disturbance. A number of other cetaccan species not yet encountered could occasionally occur in Ghana’s waters, e.g., Balaenoptera brydei, Mesoplodon densimstris, Kogia breviceps, Stenella corruleoalba and Delphinus delphis.