Precise giants: New research reveals how blue whales find food in a vast ocean

Precise giants: New research reveals how blue whales find food in a vast ocean MBARI biological oceanographer John Ryan shares how a team of researchers used bio-logging tags and satellite data to learn how blue whales find dense swarms of krill. Why It MattersDespite protections, blue whales remain endangered, primarily from the risk of collisions with ships. Understanding where and how these ocean giants feed will help resource managers and policymakers safeguard their future. Biological oceanographer John Ryan leads MBARI research to understand the ecology of whales, from monitoring how ocean conditions change the food web to using whale vocalizations to track their movements. Image: Olívia Soares Pereira © 2026 MBARIMBARI’s Blue Whale Observatory uses a suite of technologies to study these endangered animals and their primary food source, krill, in the Monterey Bay region. The findings from this body of research can help resource managers protect these majestic animals.Through the observatory, MBARI scientists and a network of collaborators integrate a variety of sensing methods to collect data about whale behavioral ecology, including:Passive acoustic sensing to listen to whales.Active acoustic sensing to monitor the location and behavior of the whales’ prey.Annual monitoring of the California Current Ecosystem by NOAA Fisheries.Meteorological and oceanographic data to explore the ecosystem processes that influence whale-krill dynamics and interactions.Biologging with electronic sensors attached to whales to record data about their activity and the conditions in the marine environment around them.A new paper in the scientific journal Current Biology highlights findings from the team’s latest study in this ongoing body of work to understand whale ecology. We sat down with John Ryan, a biological oceanographer at MBARI and the lead author of this study, to learn more. What questions were you trying to answer with this research?Blue whales must take in an enormous amount of calories to sustain their massive bodies and long-distance migrations. We know that they need very dense swarms of krill to make the intensive effort of feeding worthwhile, but krill swarms can be difficult to find in the vast ocean. Our team wanted to learn more about how these giant animals locate krill swarms. Do whales sense krill swarms directly, or do they sense specific conditions in the ocean environment that guide them to krill swarms? What kinds of data did you collect for this study?The key data for this study came from two perspectives: the whales themselves and satellites that view the Earth from space. MBARI scientists collaborated with Cascadia Research Collective and Stanford University, who tagged a pair of whales to monitor their foraging behavior. Image courtesy of John Calambokidis/Cascadia Research CollectiveOur collaborators at Cascadia Research Collective and Stanford University deployed temporary, small electronic tags on whales—referred to as biologging—to record whale movement, activity levels, and feeding habits as well as conditions in the immediate surrounding ocean environment. The feeding behavior of the whales also helped us interpret the density of the krill swarms, based on previous research.Orbiting satellites, carrying radar altimeters and NOAA infrared thermal sensors, provided detailed descriptions of the physical environment around the whales. The altimeters defined the ocean surface topography that determined ocean circulation patterns, and the infrared sensors identified the thermal fronts targeted by the foraging whales. What did you find? We were able to carefully piece together this large body of data to look at the relationship between environmental dynamics in the ocean and the whales’ foraging behavior. Think of it as working on a jigsaw puzzle with pieces of all shapes and sizes. Combining these puzzle pieces provided valuable insights into the phenomenal sensory capabilities of blue whales. Data show that these foraging blue whales respond to their constantly circulating environment in precise, systematic ways, pinpointing their feeding efforts along thermal fronts—narrow zones of ocean with strong temperature gradients.The whales would locate a thermal front near the ocean surface, then dive deeper in the water to search for dense krill swarms. They would move from the cool side of the thermal front toward the warm side when searching for krill swarms and would feed intensively once they located them.The whales’ responsiveness to thermal fronts occurred day and night, with or without the result of successful feeding. The precise, systematic movement behaviors of blue whales tell us that they can not only sense temperature, but also track where and how temperatures change near the ocean surface, suggesting a remarkable capacity for memory, comparison, and orientation. What makes you most excited about this research project?Blue whales must locate dense krill swarms that are sparsely distributed in a vast ocean. Among other strategies, they can pinpoint thermal fronts, where temperature gradients are strong and food is plentiful. Image courtesy of Duke Marine Robotics and Remote SensingMy favorite part of studying blue whale behavior is marveling at this magnificent species. I’m very excited about recognizing at least one dimension of blue whale sensory perception. This discovery has broader implications for understanding many species that rely on dense prey aggregations to survive. It opens the door to explore whether this is a fundamental foraging strategy across diverse predator species, enabling them to precisely localize feeding effort where prey are most concentrated.Perhaps most importantly, this discovery enables us to support the protection of these endangered animals through a greater understanding of how they live, and how their lives intersect with human activities that unintentionally threaten the whales. As they went about their lives consuming tonnes of krill, these foraging blue whales moved through habitat that is regularly transited by gigantic ships. This research was made possible by the David and Lucile Packard Foundation through its longtime support of MBARI’s work. Whale biologging tag deployments were funded by NOAA and conducted under NMFS Permit # 21678.Research Publication:Ryan, J.P., A.I. Vanegas Ledesma, W.K. Oestreich, K.J. Benoit-Bird, J.A. Goldbogen, J. Calambokidis, and J.A. Fahlbusch. 2026. High-precision localized feeding by blue whales. Current Biology. https://www.cell.com/current-biology/fulltext/S0960-9822(26)01020-1For additional information or images relating to this article, please email pressroom@mbari.org. Share Like this? Share it! Share on Facebook Share on Twitter Share on LinkedIn Share on Email