# Automatic Detection and Unsupervised Clustering-Based Classification of Cetacean Vocal Signals +
### Data Collection  
The underwater acoustic data used are obtained from two open-source databases--Mobysound database ([[http://www.mobysound.org/](http://www.mobysound.org/)]([http://www.mobysound.org/](http://www.mobysound.org/)) accessed on 1 January 2023) and Watkins Marine Mammal Sound database ([[https://cis.whoi.edu/science/B/whalesounds/index.cfm](https://cis.whoi.edu/science/B/whalesounds/index.cfm)]([https://cis.whoi.edu/science/B/whalesounds/index.cfm](https://cis.whoi.edu/science/B/whalesounds/index.cfm)) accessed on 1 January 2023). Mobysound database is a reference archive for studying the automatic recognition of marine mammal sounds [30]. The Mobysound database provides open-source information on different types of sounds from various species of marine mammals in a wide range of geographic areas. Watkins Marine Mammal Sound Database, built by [PERSON], is a resource that contains approximately 2000 unique recordings of more than 60 species of marine mammals [31]. The waveform of vocal signals was selected from five cetacean species, including common dolphin (_Delphinus delphis_), right whale (_Eubalena glacialis_), [PERSON]'s dolphin (_Grampus griseus_), pilot whale (_Globicphala macrorhynchus_), and beaked whale (_Mesoplodon densirostris_). The audio files of [PERSON]'s beaked whale (BW), pilot whale (PW), and [PERSON]'s dolphin (RD) are from the 3 rd International Workshop on Detection, Classification, Localization, and Density Estimation (DCLDE) of Marine Mammals using passive acoustics in Mobysound. Right whale (RW) upsweep sound and a set of background noise data with no whales come up from the 6 th workshop in Mobysound. The audio files of common dolphins (CD) are from Watkins Marine Mammal Sound Database. The reason we chose these species is they are common species of cetaceans, and these species' data are complete and adequate, so they are fit for our experiment requirements. Firstly, the amount of data is large enough that each species has a minimum duration of more than half an hour. Secondly, the recordings may include different types of vocal signals, such as echolocation click, whistle, and burst pulse. These recordings have been visually confirmed as originating from some specific single species, which means the vocal signals from a recording belong to the same species. According to the relative README files, it is known that each sound file is a single continuous recording--a sequence of digital samples from one or more hydrophones saved in WAVE format. In the same audio file, there are different types of vocalizations. The total data are contained within 194 waveform files of 25.3 h duration, or approximately 1.54 G of data. Nevertheless, due to ambient noise and non-stationary characteristics, the wave data in sound files cannot yet be utilized directly in automatic call recognition research. Consequently, automatic detection and feature extraction are essential for unsupervised classification.  
The original data are collected using one recording configuration in or near one geographic area over one relatively short time span. Some details will vary from one sound dataset to another; for example, recorders of right whales were deployed in arrays of six or ten devices, a single channel having been stripped out and converted to 16 bit wav file format with a sample rate of 2 kHz. More details of other datasets can be found in the descriptions of databases in [30; 31].