Deep diving behaviour in oceanic manta rays and its potential function

October 2025

Calvin S. Beale, Ferawati Runtuboy, Abraham Sianipar, Angela J. E. Beer, Mark Erdmann, Edy Setyawan, Lydia Green, Clinton A. J. Duffy, Samantha Andrzejaczek, Barbara Ann Block, Kerstin Forsberg, Mark Meekan, Adrian C. Gleiss

Keywords: Manta Ray • Oceanic Manta Ray • Deep Diving Behaviour • Navigation, • Satellite Telemetry, • Movement Ecology • Marine Megafauna

Summary: This study investigated the function of deep-diving behaviour in oceanic manta rays (Mobula birostris) using data from 24 satellite-tagged individuals in Indonesia, Peru, and New Zealand. Of nearly 47,000 recorded dives, 79 exceeded 500 m. These extreme dives featured rapid descents, brief pauses at depth, and slow ascents, without signs of feeding. They occurred more often far from continental shelves and before long-distance movements, suggesting a navigational or environmental-surveying function rather than foraging, providing new insight into manta movement ecology.

Abstract

“Deep dives are performed by a range of marine megafauna, yet their function remains poorly understood. Proposed functions include foraging, predator avoidance, and navigation, but limited fine-scale data have hindered rigorous testing of these hypotheses. Here, depth time-series data from eight recovered and 16 non-recovered satellite tags deployed on oceanic manta rays (Mobula birostris) in Indonesia, Peru, and New Zealand were examined to characterise extreme dives and identify their potential function. From a total of 46,945 dives, 79 extreme dives (>500 m) were recorded, 11 of which were documented from recovered tags and associated high sampling frequency. Extreme dives were distinguished by rapid descents (up to 2.9 ms⁻¹), brief horizontal “steps” at depth, gradually slowing ascents, and extended periods spent near the surface both before and after diving. Unlike typical foraging dives, no substantial bottom phase was observed, and vertical oscillations—expected if feeding at depth—were absent. Extreme dives also occurred more frequently within increasing distance from the continental shelf edge as well as preceding periods of high 72 h distance travelled, indicating they may inform subsequent movements. We propose that extreme dives enable oceanic manta rays to survey the properties of the water column, likely gathering environmental cues—such as temperature, dissolved oxygen, or geomagnetic gradients—to guide navigation and/or the decision to leave or remain in a general area. In open-ocean environments where external reference points are absent, such costly but infrequent dives may provide critical information for long-distance movements. Our results offer new insights into the role of extreme diving behaviour in oceanic manta rays and highlight the importance of fine-scale data for understanding deep-diving behaviours in marine megafauna.”

Full publication

Author Affiliations

  • Harry Butler Institute, Murdoch University

  • Raja Ampat Manta Project, The Manta Trust Affiliate Project

  • University of Papua

  • Environmental and Conservation Sciences, Murdoch University

  • Bogor Agricultural Institute

  • Elasmobranch Institute Indonesia

  • Maritime and Fisheries Polytechnic

  • Re:Wild

  • Institute of Marine Science, The University of Auckland – Waipapa Taumata Rau

  • Manta Watch Charitable Trust

  • Marine Species Team, Department of Conservation

  • Hopkins Marine Station, Stanford University

  • Planeta Océano

  • Migramar

  • University of Western Australia Oceans Institute

Funding (found in the acknowledgements of the paper)