Data from: Seasonal and diel cycles of fin whale acoustic occurence near Elephant Island, Antarctica
Citation
Burkhardt, Elke (2021), Data from: Seasonal and diel cycles of fin whale acoustic occurence near Elephant Island, Antarctica, Dryad, Dataset, https://doi.org/10.5061/dryad.cjsxksn3m
Abstract
This study investigates the relevance of the Elephant Island region for Southern Hemisphere fin whales (Balaenoptera physalus) in their annual life cycle. We collected three years of passive acoustic recordings (Jan 2013 to Feb 2016) northwest of EI to calculate time series of fin whale acoustic indices, daily acoustic occurrence, spectrograms, as well as abundance of their 20-Hz pulses. Acoustic backscatter strength, sea ice concentration and chlorophyll a composites provided concurrent environmental information for graphic comparisons. Acoustic interannual, seasonal and diel patterns together with visual information and literature resources were used to define the period of occupancy and to infer potential drivers for their behaviour. Spectral results suggest that these fin whales migrate annually to and from offshore central Chile. Acoustic data and visual information reveal their arrival at EI in December to feed without producing their typical 20-Hz pulse. For all three years, acoustic activity commences in February, peaks in May and decreases in August, in phase with the onset of their breeding season. Our results emphasize the importance of EI for fin whales throughout most of the year. Our recommendation is to consider EI for establishing a marine protected area to expedite the recovery of this vulnerable species.
Methods
See publication.
Usage Notes
Description of data files used in Burkhardt et al. “Seasonal and diel cycles of fin whale acoustic occurence near Elephant Island, Antarctica”
Daily_Acoustic_Presence.xlsx
|
Descriptor |
Content |
|
Day |
Date of day analyses [dd.mm.yyyy] |
|
FinWhale |
1 if at least one fin whale 20-Hz call detected during that day. |
Call_Abundance.xlsx
|
Descriptor |
Content |
|
CorrOrder |
Consecutive numbering of analysed files |
|
DateFile |
Date of start of analysed file [yyyymmdd] |
|
File |
Time of start of analysed file [HHMMSS] UTC |
|
Date |
Consecutive number in analysed days (omitting days not analysed) |
|
UTC_long |
Time of start of analysed file [HH:MM:SS] UTC |
|
UTC |
Time of start of analysed file [HH:MM] UTC floored to the lesser full 10-minutes |
|
TimeEI(UTC-3.40) |
Local time of start of analysed file [HH:MM] LT floored to the lesser full 10-minutes |
|
UTC+3.30fuerAchsen0PunktBei20.30 |
Helper variable facilitating a shift of the x-axis |
|
Obvious Calls (OC) |
Number of obvious 20-Hz calls in 10-min file |
|
Category |
Classification of OC according to legend of Fig. 6 |
|
NAN |
set to 1 if files not analysed for technical reasons |
AWI251-01_AU0231_LTS_SNR.mat
Matlab data file containing Long Term Spectrogram Data from Aural 0231. Variable naming is self-explaining.
MVBS_sn5848_mooring_AWI251-1.mat
Matlab data file containing mean volume backscatter data from ADCP. Variable naming is self-explaining.
Funding
Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Award: not applicable