Passive acoustic monitoring of killer whales in the Gulf of Alaska 2019-2021

Hannah Myers, University of Alaska Fairbanks

Defining a marine mammal population’s calling rate can enable acoustic density
estimation. We used killer whale dialects, long-term photo-identification, and year-round acoustic data across multiple locations to establish calling rates for three killer whale populations. This dataset includes acoustic detections of the AD8 and AD16 pods of southern Alaska resident (fish-eating) killer whales, as well as detections of the Gulf of Alaska transient (mammal-eating) and AT1 transient (mammal-eating) populations.

These populations and pods were recognized using published call catalogues as well as field recordings during which the animals present were photographically identified.

The number of discrete calls in each four- or five-min recording was counted. For resident killer whales, the number of animals present is the number of animals photographically documented that year in the pod; for transients, it is the mean number of animals documented over long-term vessel survey efforts.

Establish calling rates for passive acoustic density estimation of three populations of killer whales.

This dataset includes some overlap with "Passive acoustic monitoring of killer whales in the northern Gulf of Alaska" which collects data from 2016 - 2020 while this dataset collects data from June 2019 - Aug 2021.

For transient populations, the mean number (non-integer) of animals in vessel survey encounters was calculated and stored in number_of_animals. obs_count for these records is blank, indicating presence-only.

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 OBIS-SEAMAP)
population	Killer whale population
species	Species name
sp_tsn	Taxonomic Serial Number added by OBIS-SEAMAP
location	Passive acoustic monitoring sensor location name
latitude	Approximate latitude of sensor in decimal degrees
longitude	Approximate longitude of sensor in decimal degrees
date	Date of the detection
ak_decimal_time	Start time of the detection in hours
time	Time of the sighting at GMT
total_calls	Total calls
calling_time_sec	Calling time in seconds
recording_length_sec	Recording length in seconds
mean_snr_nist_quick	definition not provided
obs_count	Number of animals; Blank for transient populations
number_of_animals	Number of animals in original format. mean number of animals encountered in vessel surveys for transient populations
pod	Pod ID
other_pods_present	definition not provided
geom	Geometry field added by OBIS-SEAMAP