Passive acoustic monitoring (PAM) data were collected by the Perennial Acoustic Observatory in the Antarctic Ocean (PALAOA) near Neumayer Station III at 70.4261° S, 8.2161° W, on the Ekström ice shelf, Antarctica. This long-term observatory was set up in 2005 (Kindermann et al. 2007, hdl:10013/epic.30936.d001). After modifications of the hardware setup in December 2014, PALAOA collected passive acoustic data using a Sono.Vault recorder (manufactured by develogic GmbH, Hamburg, Germany). From 01 January 2021 to 31 December 2021, PALAOA recorded continuously at a sample rate of 96 kHz, at 155 m depth. Further details about the data acquisition and processing of this data set can be found in the accompanying metadata file (see Additional metadata) as well as the data processing report (see Data Processing Report). Passive acoustic data archived here represent data processing Level 1+, according to the standards defined in the associated Standard Operating Procedure (SOP) Glossary (Thomisch et al. 2023a). Further information on data processing with regard to data preparation and standardization can be found in the associated SOP Part 1: Data preparation and standardization (Thomisch et al. 2023b). We thankfully acknowledge the support of the Neumayer Station overwintering teams, and in particular of the radio operators, in maintaining and operating PALAOA.

Each daily .tar contains the 10-minute audio files (.wav format) collected during the respective day.