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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