Deep Panuke whale Acoustic 2003

Marielle Thillet, Deep Panuke Project, Encana Corporation

We present marine mammal observation statistics, high-frequency seismic source characteristics, and example denoising of marine mammal acoustical recordings using data collected during the mitigation and monitoring program for a 3-D seismic survey by Encana Corporation, Calgary, Alberta, Canada, in the northwest Atlantic during 2003. Marine mammals were observed both visually and acoustically. No marine mammal incidents or adverse reactions were observed during the survey.

Acoustical observations were made by the Seamap Passive
Acoustic Cetacean Monitoring System (SPACMS), consisting of
two hydrophones placed 50 m apart, towed ahead of and to one
side of the seismic source. Visual and acoustical detections were uncorrelated, indicating the complementary nature of the two observational techniques. Visual detections were more common per hour of effort than acoustical detections. Acoustical detection rates showed no significant day–night difference.

Marine mammals appeared to have avoided very close ranges (100 m) from the seismic array during seismic acquisition, but the overall number of marine mammals in the observable radius (1–2 km) did not change significantly when the seismic source was “on” compared to “off.” Marine mammals were observed in larger groups and appeared to have become less vocal when the seismic source was active. It should be noted however, that the results from this data gathering effort may be affected by potential sources of bias (such as the combination of data from toothed and baleen whales).

Signal processing of seismic source signatures indicated some
high-frequency energy content consistent with expectations from
earlier work. This analysis confirmed that most of the seismic
energy was concentrated at lower frequencies (500 Hz). No
low-frequency comparisons with near-field data could be made
due to the geometry of the SPACMS recording hydrophones
and seismic source, which resulted in the Lloyd’s mirror effect
obliterating low-frequency components in the SPACMS records.
A wavelet-based denoising method was applied to improve the visibility of marine mammal vocalizations on a spectrogram display.

N/A

Visual data collected in this survey are registered on OBIS-SEAMAP separately as the Deep Panuke whale sightings 2003 dataset.

Overview

This section explains attributes included in the original dataset. OBIS-SEAMAP restricts the attributes available to the public to date/time, lat/lon and species names/counts only. Should you need other attributes described here, you are encouraged to contact the data provider.

Attributes described below represent those in the original dataset provided by the provider.
Only minimum required attributes are visible and downloadable online. Other attributes may be obtained upon provider's permission.

Attributes in dataset

Attribute (table column)	Description
oid	Unique ID number (generated by SEAMAP)
obs_date	date of observation
time_fmt	Time in GMT
obs_time	time of observation
depth	Water depth in meters
location	Lat/Long of Vessel
latitude	Latitude in decimal degrees
longitude	Longitude in decimal degrees
report_no	Sighting Report No.
animal_location	Lat/Long of Mammal
observed	Acoustic or Visualization Indication of Species
sp_obs	Species observed
sp_tsn	ITIS taxonomic serial number. This field added by OBIS-SEAMAP
obs_count	Number of animals
heading	Vessel Heading
bearing	Bearing of Mammal to Vessel
range	Range of Mammal
comments	Comments