Scientists survey for false killer whales beyond known range in Hawai‘i waters

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

Aboard the NOAA Ship Oscar Elton Sette from April 23 to May 22, Pacific Islands Fisheries Science Center scientists are conducting their survey for Continued Observation of Pseudorca Extent (SCOPE).

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 area.

Scientists estimate that false killer whales are relatively abundant in this area, but the scientists do not know which population they belong to.

While aboard the NOAA vessel, scientists 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.

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.

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 allowable levels and is the focus of the False Killer Whale Take Reduction Team.

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.