evaluation de la diversite des cetaces dans les eaux environnantes de nosy-be, nosy mitsio et nosy iranja, nord-ouest de madagascar

Abstract

As part of the project of establishment of Marine Protected area Ankarea and Ankivonjy in the
Northwest of Madagascar, a study of cetaceans was done at Nosy Mitsio, Nosy-Be and Nosy Iranja from 2011
to 2013. The research was conducted at the three sites for 98 days spread over three seasons with observation
769.99 hours efforts 8 077.80 km transect and identified 12 species of cetaceans: Balaenoptera musculus,
Balaenoptera omourai is a newly identified species in the Western Indian Ocean, Megaptera novaeangliae,
Physeter macrocephalus, Globicephala macrorhynchus, Lagenodelphis hosei, Sousa plumbea, Tursiops
aduncus, Tursiops truncatus, Ziphius cavirostris, Stenella longirostris and Stenella attenuata. 209 observations
of cetacean 8163 individuals were carried out with 62 baleen whale; Stenella represent the majority of small
cetaceans observed. We saw a large abundance of observation in Nosy Iranja with 0,324 group per hour, 0.279
group per hour on Nosy Be and only 0.085 group per hour Nosy Mitsio. Baleen wha