Submerged, stationary echosounder (WBAT, Kongsberg Maritime, 200 kHz) recordings from Oslofjord, Norway between February 2020 and April 2023

A WBAT (Simrad/Kongsberg Maritime) autonomous echosounder was deployed in the inner Oslofjord for several multi-day periods between 2020 and 2023, in total amounting to about 100 days of recordings. Recording stations were in the innermost branch of Oslofjorden, (Bunnefjorden; 150 m depth; 59°47.6°N, 010°43.1°E), as well as at the 100 m deep station Midtmeiet (59°48.6°N, 010°32.5°E), at Spro (160 m; 59°45.4°N, 010°34.4°E) and Elle (155 m; 59°38.7°N, 010°37.4°E). The WBAT was deployed either on the seafloor or in an anchored floating rig. The transducer was facing the surface during all events. The WBAT was usually programmed to record continuously for several days at ping intervals around 0.5 s and pulse durations of 128 or 256 µs, thus allowing high resolution recordings of the movements and distribution of pelagic animals such as krill and fish over time. The acquisition mode was usually set to fast to allow higher ping rates. After recovery, the .ra files were postprocessed to .raw using the EK Mission Planner software. Several events include more than one recording period (phases). During one event, the WBAT was programmed to record only in the four hours around noon at preprogrammed dates, otherwise, recordings were continuous. Calibration values for the WBAT were obtained on the 21.01.2021. The calibration results are stored in the files "CalibrationDataFile-D20210121-T180910_128mus.xml" and "CalibrationDataFile-D20210121-T182003_256mus.xml" and have to be applied to the raw files before analysis. The dataset contains 16 events with in total 17136 raw EK80 files with file sizes between 7 and 105 MB, in total ca. 1.8 TB.