2023_programme: Exploring the underwater soundscape in a Portuguese coastal region

• Session: 21. Underwater Noise - Modelling and Measurements
  Organiser(s): Alexander Gavrilov
• Lecture: Exploring the underwater soundscape in a Portuguese coastal region
  Paper ID: 1930
  Author(s): Almeida Diana, Cruz Erica, Vaz Guilherme
  Presenter: Cruz Erica
  Abstract: Due to the increasing of anthropogenic activities in the ocean, animals are exposed to a variety of sounds, such as shipping, seismic exploration, sonar and construction of offshore infra-structures. Noise from these activities may change the ocean noise level, in a particular area. Recently, the European Union aimed to regularize the underwater noise under the Marine Strategy Framework directive, which stablishes several criteria to monitor and assess the spatial distribution, temporal extent and the levels of anthropogenic noise. This is particularly crucial because marine mammals rely on sound to communicate, socialize and searching for food and underwater noise might be produced in the same frequency amplitude as these animals use and hear sounds.\n\nPassive acoustic monitoring (PAM) is widely used to characterize the soundscape of a habitat by assessing noise source, animal vocalisations and other biodiversity sounds, in a given location and time. In this study, we analyse the soundscape of a coastal region in Portugal in two time-frames, using data from PAM hydrophones deployed in Sesimbra region. The presence/absence of dolphins was estimated through the identification of whistles and other vocal repertoire like gulps and grunts and anthropogenic noise level was measured. Environmental metrics, such as weather condition (tide state, wind speed) and AIS (Automatic Ship Identification System) data were used to explain noise levels.\n\nThis study pretends to give an initial view of Sesimbra underwater soundscape, where a resident population of bottlenose dolphins is known and a technology free zone was implemented. The Sado-Estuary nature reserve is located adjacently to the study-area, where cargo ships, fishing and recreational activities are known to occur, highlighting the importance of acoustic monitoring projects in this region. The overall information of this study permit the development and training an automatic algorithm to detect dolphin vocalizations, which requires accurate and rigorous scientific data.
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• Corresponding author: Ms Diana Almeida
  Affiliation: Blue Ocean Sustainable Solutions, Lda
  Country: Portugal
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