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Pascal Data

PASCAL was a dedicated cetacean acoustic survey in the California Current off the U.S. West Coast in August and September 2016. Background information on this survey as well as preliminary analysis are provided in Keating et al. (2018). A map of drift tracks is provided in Figure 1.

Map of the west coast of the United States with plots of all successful PASCAL drifts shown as black and white lines that represent their geoposition during the drift. The west coast Wind Energy Areas are outlined in purple, and shipping traffic lanes are outlined in yellow. Latitude is on the x-axis, and Longitude is on the y-axis. Bathymetry is shown with light blue for the shelf and slope waters, and dark blue for deep ocean waters. A 100 m and 200 m isobath line is provided.
Figure 1: Plot of all successful drifts deployed during the PASCAL Survey. Drifts are shown as black/white lines; Wind Energy Areas are outlined in purple, and shipping lanes for entry to San Francisco Bay and in Southern California Bight are outlined in yellow

Data were analyzed following methods consistent with the Adrift data analysis, with slight modifications to address duty cycled data. The power spectral density plots (PSD) can be found online.

Each of the major odontocete groups were detected during the PASCAL study (Figure 2).

Hourly presence of sperm whales (top left), beaked whales (top right),dolphins (lower left), and NBHF (lower right) for the PASCAL survey. The number of hours for combined deployments is provided on the y-axis, and the date on the x-axis, with seasons shaded in blue for winter, green for upwelling, and yellow for the post-upwelling season (all effort for PASCAL was during the post-upwelling season). Effort is outlined with a black line, and hours of effort with detections are highlighted in red. Daily deployment hours ranged from 24 to over 300 hours per day, depending on the number of acoustic recorders deployed per day. Detection of all species varied based on the number and location of acoustic recorders deployed on that date. The detection of all odontocete species varied over the timeframe of the survey.
Figure 2: Hourly presence of sperm whales, beaked whales, dolphins, and NBHF during the PASCAL 2016 survey. Hourly presence (x axis) of sperm whales (top left), beaked whales (top right), dolphins (lower left), and NBHF (lower right) for months (y axis) and seasons (color bands) during the PASCAL 2016 survey. Black lines represent total available hours (effort) and bottom graph shows total effort for survey. Blue shading represents winter, green represents upwelling, and yellow represents the post-upwelling oceanographic season.

Blue whale detections were dominated by song, as the low hourly presence of D calls indicates that A/B (song) calls dominated the blue whale detections (Figure 3). Likewise, detection of fin whales was dominated by 20 Hz calls (Figure 3). There were no calls associated with Bryde’s or Gray whales.

Hourly presence of blue whales (top left), blue whale D calls (top right), fin whale 20 Hz calls (lower left), and fin whale 40 Hz calls (lower right) for the PASCAL survey. The number of hours for combined deployments is provided on the y-axis, and the date on the x-axis, with seasons shaded in blue for winter, green for upwelling, and yellow for the post-upwelling season (all effort for PASCAL was during the post-upwelling season). Effort is outlined with a black line, and hours of effort with detections are highlighted in red. Daily deployment hours ranged from 24 to over 300 hours per day, depending on the number of acoustic recorders deployed per day. Detection of all species varied based on the number and location of acoustic recorders deployed on that date. The proportion of total hours with blue whale song (A/B calls, or non- D calls) and fin whale song (20 Hz calls) were very high at the end of the survey effort, while blue whale D calls and fin whale 40 Hz calls remained low for the entire survey.
Figure 3: Hourly presence of blue whales (all calls), blue whale D calls, fin whale 20 Hz, and fin whale 40 Hz during the PASCAL 2016 survey. Hourly presence (x axis) of blue whales (all calls, top left), (b) blue whale D calls (top right), fin whale 20 Hz (lower left), and fin whale 40 Hz (lower right) for months (y axis) and seasons (color bands) during the PASCAL 2016 survey. Black lines represent total available hours (effort) and bottom graph shows total effort for survey. Blue shading represents winter, green represents upwelling, and yellow represents the post-upwelling oceanographic season.

There were few hourly detections of humpback whales (hourly presence plots can be found in our GitHub Repository. Most of the PASCAL deployments were further offshore than the Adrift deployments, and this offshore distribution may be the reason for such low detection rates.

There were a few calls associated with sei and minke whales. There is little known about the vocal repertoire of sei whales in the Pacific Ocean, although a single encounter with four loud low-frequency downsweeps were detected and considered as ‘possible’ sei whale vocalizations (see spectrogram in GitHub Repository. Minke whale boings are seasonal vocalizations and more frequently detected during the winter.

A complete list of successful drifting acoustic recorder deployments during the PASCAL survey are provided in Table B‑1 . Sites include Washington (WAS), Columbia River (COL), Oregon (ORE), Humboldt (HUM), Mendocino (MND), Point Arena (PTA), Monterey Bay (MBY), Morro Bay (MOB), Channel Islands (CHI), San Diego (SND), and Baja California Norte (BCN). See Figure XXX for more information on regions.