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de Noronha Gamito Afonso dos Santos, Manuel Eduardo
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- Changes in the acoustic behavior of resident bottlenose dolphins near operating vesselsPublication . Luís, Ana Rita; Couchinho, Miguel N.; Santos, Manuel Eduardo dosPublished for the Society for Marine Mammalogy, Marine Mammal Science is a source of significant new findings on marine mammals resulting from original research on their form and function, evolution, systematics, physiology, biochemistry, behavior, population biology, life history, genetics, ecology and conservation. The journal features both original and review articles, notes, opinions and letters. It serves as a vital resource for anyone studying marine mammals.
- Raise your pitch! Changes in the acoustic emissions of resident bottlenose dolphins in the proximity of vesselsPublication . Veiga Sobreira, Filipa; Luís, Ana R.; Alves, Inês S.; Couchinho, Miguel N.; dos Santos, Manuel E.Maritime traffic is a major contributor of anthropogenicdisturbance for cetaceans, especially for coastal populations,such as that of resident common bottlenose dolphins(Tursiops truncatus) in the Sado estuary (Portugal). Animalshave been found to adjust their vocal behavior by changingvocal rates, or call frequency and/or duration, to overcomemasking effects of underwater noise. To evaluate the poten-tial impacts of boat traffic on the acoustic behavior of thesedolphins, emission rates and acoustic characteristics of whis-tles and burst-pulsed signals were analyzed with and withoutboats operating nearby. In this study, no significant differ-ences were found for emission rates of each type of vocalelement in the presence of vessels. However, significant dif-ferences were found in acoustic parameters, namely changesin frequency and duration, for whistles and for pulsed sounds(creaks, grunts, squeaks, and gulps). These changes, such as ashift in vocal frequencies and production of shorter signals,may represent behavioral strategies to compensate for thenoisy environment. Although resident bottlenose dolphins inthe Sado region seem to have developed some tolerance tovessel noise, continuous noise exposure and noise-inducedfrequency shifts in vocal outputs could have indirect fitnesscosts for this population