A new study reveals that short-finned pilot whales off Hawaiʻi consume between 82 and 202 squid daily to fuel their deep dives. Researchers tagged eight whales to track their feeding behavior, estimating the regional population devours about 88,000 tonnes of squid annually. Hawaiian waters appear robust enough to sustain this demand, supporting the species' stability.
Short-finned pilot whales (Globicephala macrorhynchus) in Hawaiian waters are voracious squid hunters, plunging to depths of up to 1700 meters in search of prey. A research team from the USA, Spain, Australia, and Denmark, led by William Gough from the University of Hawaiʻi at Mānoa, investigated their dietary needs to assess population health. "These animals have been studied in locations around the world, but relatively little is known about them in Hawaiian waters," Gough noted.
To gather data, the scientists ventured into offshore waters and attached suction-cup tags to eight whales. Each tag captured motion data, video from a lighted camera, hydrophone audio of echolocation clicks, and GPS coordinates. The tags were positioned directly behind the blowhole to record feeding during dives. "Short-finned pilot whales are fairly small and quick, so we really have to pick our moment," Gough recalled. Whale sizes were estimated using a drone 25 meters above the surface.
After recovery—sometimes from as far as 50 miles away—the team analyzed 118 deep dives, averaging 39 per day and reaching up to 864 meters. Tail-beat patterns showed energy expenditure of 73.8 kJ/min during dives and 44.4 kJ/min at rest. Echolocation signals indicated about four squid captures per dive, with each squid providing roughly 560 kJ of digestible energy.
Calculations revealed individual whales need 82 to 202 squid daily, or around 73,730 per year. With up to 8,000 whales in the region, total annual consumption reaches approximately 88,000 tonnes. "These results show that short-finned pilot whales are in relatively good shape in Hawaiʻi, having found an abundant and reliable source of food," Gough concluded. The findings, published in the Journal of Experimental Biology (2025; 228 (21)), underscore the squid populations' resilience in supporting this demand.