AFSC/NMML: Beluga whale aerial survey in Cook Inlet, Alaska, 1993-2022

The National Marine Fisheries Service (NMFS) has conducted aerial counts of Cook Inlet beluga whales (Delphinapterus leucas) from 1993 to 2012, 2014, 2016, 2018, 2021, and 2022. Nearly all counts were conducted during the month of June. The routine nature of these counts and the consistency in research protocol lend themselves to inter-annual trend analyses. Beginning in 2005, an aerial survey was added during the month of August to document calving groups within the upper Inlet (north of East and West Foreland). Research protocol has been based on paired observers on the shoreward side of the aircraft and a single observer and computer operator on the offshore side independently searching for marine mammals. Data on environmental conditions, time, location, species, and inclinometer angle were collected for each sighting. The counting protocol included multiple passes near each beluga group while simultaneously collecting video footage. The counting system and observer performance has been tested through paired, independent observational effort. Information about the Cook Inlet beluga whale projects conducted at NOAA can be found here: https://www.fisheries.noaa.gov/species/beluga-whale#science.

Aerial counts and video footage of beluga whales provide the fundamental data used to calculate the abundance of and a calving index for the Cook Inlet population. The abundance estimates are applied to trends analyses to determine the status of the stock. Results from this study were the basis for adding this distinct population of whales to the list of Endangered and Threatened Wildlife.

Loaded by FGDC Metadata Uploader, batch 6553, 07-16-2015 18:03

The following FGDC sections are not currently supported in InPort, but were preserved and will be included in the FGDC export:

- Taxonomy (FGDC:taxonomy)

The user is responsible for the results of any application of this data for other than its intended purpose.

NOAA denies liability if the data are misused.

Data can be accessed at http://data.nodc.noaa.gov/cgi-bin/iso?id=gov.noaa.nodc:0133936.

There are no legal restrictions on access to the data. They reside in public domain and can be freely distributed.

User must read and fully comprehend the metadata prior to use. Applications or inferences derived from the data should be carefully considered for accuracy. Acknowledgement of NOAA/NMFS/AFSC as the source from which these data were obtained, in any publications and/or other representations of these data, is suggested.

Access

Two observers were positioned on the shoreward side of the plane and one observer and a data recorder on the offshore side. During many of the surveys, an intercom system provided communication among the observers, data recorder, and pilots, but a selective listening device was used to aurally isolate each observer position. This ensured independent sighting collection to calculate correction factors for missed beluga groups. After reporting a beluga group, the team would go off effort and the plane would fly directly over the group to obtain a sighting location. A racetrack pattern was flown around the whale aggregation and the paired observers would tally the number of animals independently and assign an overall grade to the circling pass (A to F for excellent to poor). The pass quality was based on the overall visibility of the group (accounting for sea state, sighting distance, glare, and the condition of the observation window), irrespective of the number of whales at the surface. Once the two observers recorded four high quality passes (A or B), the crew would rotate and the remaining observer and data recorder would count until they also obtained four high quality passes. In most cases, there were 16 high quality counts for each group of belugas encountered. The number of counting passes was occasionally reduced when group sizes were small (less than 10 animals) or when air traffic precluded additional circling time. All data were recorded real-time into a Microsoft Access database by a specially-designed software program. Edits were performed at the end of each survey day for quality control purposes.

All sighting data for species other than beluga whales were collected opportunistically and should be used with caution. On rare occasions (pre 2005) the GPS lost signal resulting in data gaps in the trackline data.

After each survey day, data were quality controlled by checking all hand entered information from that day including weather, sightings, species, group sizes, observer position, and comment data for errors.

IT Security and Contingency Plan for the system establishes procedures and applies to the functions, operations, and resources necessary to recover and restore data as hosted in the Western Regional Support Center in Seattle, Washington, following a disruption.