engleski

Someone turn the volume down, please! Long-term monitoring of anthropogenic noise and its relationship to bottlenose dolphin distribution in the Cres - Lošinj Archipelago, Northern Adriatic, Croatia

Cres and Lošinj archipelago represents important feeding and breeding ground for the resident population of bottlenose dolphins (Tursiops truncatus). However, in the past decade, this area has been subjected to a strong development of nautical tourism that constitutes the primary source of the underwater anthropogenic noise over the low frequencies (below 1 kHz). This is especially due to the increased number and high mobility of the fast recreational vessels that colonize the area during the summer season. The aim of this study is to identify the critical areas in terms of noise and vessel presence and to correlate this anthropogenic pressure to bottlenose dolphin distribution within the archipelago. A long – term monitoring of Sea Ambient Noise was carried out on ten predefined acoustic locations in the period January 2005 – December 2008. Acoustic recordings have been made by using a RESON TC4032 hydrophone and Pioneer DC- 88 DAT recorder. Collected data has been analyzed with SPECTRA RTA software obtaining the 1/3 octave band analysis for each acoustic sample. Data on noise and vessel presence have been correlated with data on spatial distribution of bottlenose dolphins in the area collected over the same time span. Results indicate that critically noisy areas bear some relationship to the spatial and temporal distribution of bottlenose dolphins.

anthropogenic noise; sea ambient noise; bottlenose dolphins

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