Diving behavior of the reef manta ray (Mobula alfredi) in New Caledonia: More frequent and deeper night-time diving to 672 meters

PLoS One. 2020 Mar 18;15(3):e0228815. doi: 10.1371/journal.pone.0228815. eCollection 2020.

Abstract

The interest in reef manta rays (Mobula alfredi) from the scientific community is growing in reaction to the major decline of populations around the world. Studies have highlighted the need to further investigate the spatial ecology of this species to inform conservation and management initiatives. Here we briefly report the results from nine SPLASH10-F-321A pop-off satellite archival tags (PSAT-tags) deployed in New Caledonia that recorded the world's deepest known dives for reef manta rays. All tagged individuals performed dives exceeding 300 m in depth, with a maximum depth recorded of 672 ± 4 m. Diel comparisons revealed that most of the deepest dives occurred during night-time. We hypothesize this deep-diving behaviour is employed to access important food resources at these depths during the night and may also indicate that zooplankton abundance in the surface waters surrounding New Caledonian coral reefs is insufficient to sustain these megafauna. These results add new information on the habitat use of this species in a region where manta behaviour has not previously been studied, and increase the known depth range of M. alfredi by more than 200 m.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Behavior, Animal
  • Coral Reefs
  • Diving / physiology*
  • Feeding Behavior
  • Female
  • Male
  • New Caledonia
  • Satellite Communications
  • Skates, Fish / physiology*

Grants and funding

We express particular thanks to the Keidanren Nature Conservation Fund (KNCF) who funded the study through the SATO YAMA UMI Project and Conservation International. We thank the Southern Province of New Caledonia for their financial support in the form of a scholarship to HL. We also gratefully acknowledge the financial support of MAC3 Impact Philanthropies, William Brooks, Pam Rorke Levy, Audrey and Shannon Wong, Daniel Roozen and Kris Norvig in sponsoring satellite tags, and we thank OceanMax for supplying the Propspeed antifouling coating for our tags. Conservation International played a role in the study design and the data collection but had no role in analysis, decision to publish, or preparation of the manuscript. The remaining funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.