Banca de QUALIFICAÇÃO: DIANA CARVALHO DE FREITAS

OCCURRENCE AND BIOACOUSTIC PATTERNS OF CETACEANS IN THE NORTH AND NORTHEAST REGIONS OF THE BLUE AMAZON

Acoustic behavior, Bioacoustics, Distribution, Mysticetes, Odontocetes, Humpback Whale, Melon-headed Dolphin

Cetaceans can be found in oceanic, coastal and estuarine regions around the world. Currently, 92 species are recognized, and most of these, because they have oceanic habits, are poorly studied. In addition to inhabiting remote areas, cetaceans are present in low densities in large bodies of water and live most of their lives submerged. These characteristics make studying cetaceans a major financial and logistical challenge. Therefore, alternative methods have been proposed to facilitate the collection of ecological and behavioral data, such as: the use of Opportunity Platforms and Passive Acoustic Monitoring (MAP). This work uses data collected with these two tools in order to increase our knowledge about cetaceans that occur in the North and Northeast of the Blue Amazon. Chapter 1 of this document deals with the occurrence of humpback whales in an area further north of the boundary of use considered for the species on the Brazilian coast. The presence of humpbacks was recorded through MAP carried out in the Barreirinhas Basin, Maranhão, in 2016. We describe the song of the males and compare the units sung with the song composition of the males of Itacaré, Bahia. We conclude that the male singers from the Barreirinhas Basin belong to Reproductive Stock A, the only stock that occurs on the Brazilian coast, and suggest an expansion of the area that is commonly considered to be used by Stock A. In Chapter 2, we describe an unprecedented visual and acoustic record of melon-headed dolphins in the equatorial portion of the South Atlantic Ocean. This record was made possible by the use of a Brazilian Navy ship as an Opportunity Platform. The observed group had 300 to 400 individuals and was moving quickly, with an occasional bounce. We present the acoustic parameters of 225 dolphin whistles and compare these data with records made of the species in other oceans. Whistle frequencies ranged from 4.74 to 31.47 kHz and whistle duration from 0.03 to 2.80 seconds, with a mean (±SD) of 0.44 seconds (±0.40 seconds). In addition, we used data from the Marine Mammal Monitoring Support System (SIMMAM), an online database that allows the entry of sighting data, acoustic recording and strandings of cetaceans. In SIMMAM, we searched for occurrence data of the species of interest for this study (humpback whale and melon-headed dolphin) in the North and Northeast regions of Brazil.