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Scoping it Out: A First-of-its-Kind Survey for False Killer Whales

May 06, 2024

Scientists are on a month-long survey at sea to look for Hawai‘i pelagic false killer whales far outside of their known range. What will they find?

Feeding time A false killer whale grabs a mahimahi hiding under a bucket lid, looking very much like an Avenger in the process! Credit: NOAA Fisheries/Ernesto Vazquez (Permit #25754)

Pacific Islands Fisheries Science Center scientists are spending a month at sea (April 23–May 22) aboard the NOAA Ship Oscar Elton Sette on the Survey for Continued Observation of Pseudorca Extent (SCOPE)They’re searching for pelagic false killer whales in an area they have not surveyed before and using specialized methods to collect biological data from as many false killer whales as possible.

They will use the same methods to look and listen for whales and dolphins on this mission that they have used for many years on other surveys

During SCOPE, they have increased capacity to:

  • Locate false killer whales
  • Take photo-identification images
  • Collect biopsy samples
  • Deploy satellite tags when this species is found
     

These key types of data are limited for pelagic false killer whales—including the Hawaiʻi pelagic population that has a new management area to address bycatch in the Hawaiʻi deep-set longline fishery.

A false killer whale with its dorsal fin and top of its body swimming in the ocean with the NOAA Ship Oscap Elton Sette in the background.
A false killer whale as viewed from a small boat launched from the NOAA Ship Oscar Elton Sette (in background) in order to collect biological data. Credit: NOAA Fisheries/Corey Sheredy (Permit #14097)

Scoping Out New Waters

The SCOPE study area is more than 500 nautical miles southeast of the Oscar Elton Sette’s home port of O‘ahu. Additionally, it is outside of the U.S. Exclusive Economic Zone around the Hawaiian Islands and the Hawaiʻi pelagic false killer whale management areaScientists estimate that false killer whales are relatively abundant in this area, but the scientists do not know which population they belong to. Hawaiʻi pelagic false killer whales may occur in this area along with one or more other pelagic false killer whale populations. The biological data scientists are collecting will help to distinguish the false killer whale populations found during the survey.

Map of Hawai‘i with an outline showing two boundaries around the islands that indicate the U.S. Exclusive Economic Zone and the area of the Hawai‘i pelagic false killer whale management area. The map also shows the rectangular study area southeast of the two boundaries.
Map showing the proximity of the SCOPE study area (gold box) to the Hawaiʻi pelagic false killer whale management area (green line) and the U.S. Exclusive Economic Zone (blue line) around the Hawaiian Islands (top), Johnston Atoll (middle), and Palmyra Atoll (bottom). The survey ship will depart from and return to Oʻahu. Credit: NOAA Fisheries

Why Survey for False Killer Whales? 

The boundary of the Hawaiʻi pelagic false killer whale management area is based on available biological data and reflects the known range of this population. Scientists will ultimately use the data collected during SCOPE to inform future updates to the Hawaiʻi pelagic false killer whale management area. The management area is used to evaluate impacts of the deep-set longline fishery on Hawaiʻi pelagic false killer whales. Bycatch of this population in the deep-set longline fishery currently exceeds the Potential Biological Removal, which indicates this bycatch may be affecting the ability of Hawaiʻi pelagic false killer whales to maintain a healthy population size. The False Killer Whale Take Reduction Team was established to reduce incidental death and serious injury of false killer whales in the Hawaiʻi longline fisheries.

The SCOPE study area is outside of where the deep-set longline fleet regularly fishes. However, results from this survey will play a role in the conservation and management of Hawaiʻi pelagic false killer whales. The scientists hope to learn more about this species and work toward reducing their interactions with longline gear. 

Last updated by Pacific Islands Fisheries Science Center on May 22, 2024