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In this study, we used long-term passive acoustic monitoring (PAM) to improve knowledge about the use and spatiotemporal distribution of Erignathus barbatus vocalisations. Two autonomous passive acoustic recorders were deployed between August 2014 and July 2015 in the inner and outer parts of the Kongsfjorden (Svalbard Islands, Norway) resulting in 1728 h of data recorded and 17,220 vocalisations detected. We investigated the vocalisation occurrence with respect to the presence of ice in the fjord (sea ice and glacier iceberg) and to the light cycle. The vocalisation rate varied significantly daily and monthly, and a correlation to the light and darkness turnover was shown during the period between the end of February and the first part of April. Bearded seal vocalisations, which started on 12 February and ceased on 22 June, intensified with the ice coverage peak but also continued during ice retreat, coinciding with the mating season. Additionally, a spatial displacement was highlighted from the inner to the external part of Kongsfjorden in the second part of May corresponding to the disappearance of sea ice within the fjord. This study highlights the ability of PAM to be a useful tool for both understanding abiotic and biotic processes in the marine environment, and ultimately the potential interactions between them. [ABSTRACT FROM AUTHOR]

In this study the description of underwater vocal repertoire of bearded seal in Svalbard (Norway) was extended. Two autonomous passive acoustic recorders were deployed for one year (August 2014-July 2015) in the inner and outer parts of the Kongsfjorden, and 1728 h were recorded and 17 220 vocalizations were found. Nine different vocalization classes were identified and characterized using ten acoustic parameters. The calls showed heterogeneous spectral features, but share the descending trend of frequency modulation. The different classes emerged were discriminated primarily by bandwidth and duration, and then by minimum frequency, central frequency, and maximum frequency in this order. This study represents a step forward to improve the understanding of the acoustic behaviour and the social function of these calls, and identified long passive acoustic monitoring as an effective method to assess vocal complexity and the ecology of marine species producing sounds. [ABSTRACT FROM AUTHOR]