DOI: 10.5281/zenodo.15092732
title: BioDCASE 2025 Task 2 : Development set

description: General description 



This repository contains all development data for the task 2 "Supervised Detection of Strongly-Labelled Whale Calls" of the BioDCASE 2025 challenge. It has been derived from the ATBFL library, to make a version more fitted to the challenge. ATBFL is one of the largest annotated datasets in marine bioacoustics, gathering underwater recordings around Antarctica from 2005 to 2017. Overall, the data are composed of :





6591 audio files (6004 in train set + 587 in validation set) totaling 1880 hours of recordings from 11 different deployments organized in site-year datasets (eg, kerguelen-2015);

11 CSV annotation files named after each corresponding site-year dataset. See "Annotation structure" for more details.




Folder structure 

biodcase_development_set.zip

|___biodcase_development_set/

      |____train/

            |____annotations/

                  |____site_year1.csv

                  |____site_year2.csv

                  |____...

            |____audio/

                  |____site-year1/

                        |____*.wav

                  |____site-year2/

                  |____...

      |____validation/

            |____annotations/

                  |____site_year1.csv

                  |____site_year2.csv

                  |____...

            |____audio/

                  |____site-year1/

                        |____*.wav

                  |____site-year2/

                  |____...

        

Annotation structure 
Each annotated sound event is defined by the tuple (dataset,filename,annotation,annotator,low_frequency,high_frequency,start_datetime,end_datetime), with annotation representing the class label and taking a unique value in {bma, bmb, bmz, bmd, bpd, bp20, bp20plus}. Note that these labels correspond to a more machine-readable version of the list {BmA, BmB, BmZ, BmD, BpD, Bp20, Bp20plus} described below in the section Call description. Annotator represents the short name of the expert annotator who have produced the annotation file. There is one single annotator per dataset but a same annotator may have annotated several datasets.

As calls may overlap, the set up is multi-class and multi-label : one file or segment of file file is likely to contain several classes. 

Please note that evaluation metric is IoU 1D over the temporal axis : the frequency component is provided but will not be part of the final evaluation. 

Please note that 7 classes are provided but the evaluation will only take 3 into account as calls can be gathered by similarity following this table : 




bma
bmb
bmz
bmd
bpd
bp20
bp20plus


ABZ call
ABZ call
ABZ call
Downsweep
Downsweep
Bp call
Bp call





 

Calls description

BmA, BmB, and BmZ calls are specific to blue whales (Balaenoptera musculus intermedia, Bm), while Bp20 and Bp20Plus calls are characteristic of fin whales (Balaenoptera physalus quoyi, Bp). Both species also produce downsweeps.

As described by Miller et al. (see "Related Works"), BmA calls consist of a constant-frequency tone between 25 and 28 Hz, without additional units. BmB calls are similar but followed by a partial or full inter-tone downsweep. BmZ calls contain two tonal units: A (higher frequency) and C (lower frequency). Occasionally, a B downsweep unit appears between them, forming a "Z" shape on spectrograms.

Bp20 and Bp20Plus vocalizations are pulsed calls with peak energy at 20 Hz (Bp20) and additional energy at higher frequencies (80–100 Hz) in Bp20Plus.

Downsweeps are characterized by a continuous frequency modulation from f₁ to f₂, where f₁ > f₂. Example spectrograms are available on the here, with more detailed references in Miller et al.

Dataset statistics

Train set




Dataset
Number of audio recordings
Total audio duration  (h)
Positive duration (h:m.s)
Total sound event


ballenyisland2015
205
204
02:46.32
2222


casey2014
194
194
14:12.00
6866


elephantisland2013
2247
187
16:06.58
21966


elephantisland2014
2595
216
28:08.25
20964


greenwich2015
190
32
02:03.11
1128


kerguelen2005
200
200
03:31.37
2960


maudrise2014
200
83
05:42.45
2360


rosssea2014
176
176
08:51.00
104


TOTAL
6004
1292
72:40.20
58570




Validation set




Dataset
Number of audio recordings
Total audio duration  (hour)
Positive duration (h:m.s)
Total sound event


casey2017
187
187
06:06.42
3263


kerguelen2014
200
200
11:23.02
8822


kerguelen2015
200
200
07:23.30
5542


TOTAL
587
587
24:53.14
17627




A more complete version of this table is available here, with more statistics within the different classes and more information on the recording deployments.

Evaluation set

The evaluation set for this task will be released on June 1, 2025. 

Data collection and curation

Original data were collected, curated, annotated and published by Miller, B.S., The IWC-SORP/SOOS Acoustic Trends Working Group., Balcazar, N. et al. An open access dataset for developing automated detectors of Antarctic baleen whale sounds and performance evaluation of two commonly used detectors. Sci Rep 11, 806 (2021). https://doi.org/10.1038/s41598-020-78995-8 (see Related works section)

Minor changes were brought to the original data and annotation set to fit the challenge formatting : 





adopting more consistent naming conventions, particularly for file paths. All .wav filenames now follow the format "YYYY-mm-ddTHH-MM-SS_fff.wv", and the same convention is used in the CSV files under the "filename" column. Additionally, the start and end timestamps for temporal annotation boxes are formatted as "YYYY-mm-ddTHH:MM:SS.ffffff+zz:zz", all in Zulu Time,


pooling together call-type-specific Raven tables into one CSV file per subdataset, named after the site-year annotated,

resampling all audio files at 250 Hz, the minimal original sample rate of several subdatasets. This was done to standardize sample rates and because the vocalizations of interest are very low-frequency calls (15–120 Hz), ensuring no loss of information at  sampling rate of 250 Hz


Open access

Data used in this study are publicly available under a Creative Commons 4.0 Attribution licence. It is attributed to Miller, B.S., The IWC-SORP/SOOS Acoustic Trends Working Group., Balcazar, N. et al.They can be accessed via the Australian Antarctic Data Centre at https://data.aad.gov.au/metadata/records/AcousticTrends_BlueFinLibrary

Contact info 

Please, send any feedback or question to : 

Dorian CAZAU (dorian.cazau@ensta.fr) | Lucie JEAN-LABADYE (lucie.jean-labadye@sorbonne-universite.fr) | Cléa PARCERISAS (clea.parcerisas@vliz.be)