BRIEF RESEARCH REPORT article

Front. Mar. Sci.

Sec. Marine Megafauna

Volume 12 - 2025 | doi: 10.3389/fmars.2025.1511075

Threatened cetaceans in a potential deep seabed mining region, Clarion Clipperton Zone, Eastern Pacific, August 2023

Provisionally accepted
Kirsten  F. YoungKirsten F. Young1,2*Thomas  WebberThomas Webber1Leonidas  KarantzasLeonidas Karantzas3Severina  MitevaSeverina Miteva4Grant  OakesGrant Oakes2David  SantilloDavid Santillo2Paul  JohnstonPaul Johnston2
  • 1Biosciences, Faculty of Health and Life Sciences, University of Exeter, Exeter, United Kingdom
  • 2Greenpeace Research Laboratories, Exeter, England, United Kingdom
  • 3Greenpeace Greece, 78 Kolonou Str., Athens, Greece
  • 4Greenpeace Bulgaria, P.O. Box 975, Sofia, Bulgaria

The final, formatted version of the article will be published soon.

The Clarion Clipperton Zone (CCZ) of the Eastern Pacific is an ~ 6 million km 2 abyssal area punctuated by seamounts. The CCZ is a focus for potential mining, although these are not, as yet, a commercial reality. Records from online repositories and field guides suggest that up to 30 cetacean species are present in the CCZ, though dedicated surveys have yet to be published. We report the results of a passive acoustic survey for cetaceans conducted over 13 days during summer 2023 in two blocks of the CCZ earmarked for deep seabed mining -NORI-d and TOML-e. The areas surveyed had a mean depth of 4259 m, with no charted seamounts, and 4,328 km of track (273 hours of continuous recordings. In total, there were 74 acoustic detections, with six visual encounters. We report the presence of a sperm whale (Physeter macrocephalus) (one individual), Risso's dolphins (Grampus griseus) (two groups) and common dolphins (Delphinus delphis) (one group, confirmed by visual sighting). We also acoustically encountered 70 dolphin groups that could not be identified to species level. No baleen whales, kogiids or beaked whales were detected during this short survey.Beaked whales are challenging to detect, such that a lack of detections cannot be taken to confirm the absence of such species. We confirm one threatened species present in these blocks of the CCZsperm whales -and suggest that more extensive data are urgently needed to understand the risk of harm to cetaceans that may arise from human activities, including deep-sea mining.

Keywords: deep sea mining1, minerals2, passive acoustic monitoring3, sperm whale4, oceanic dolphin5, Pacific Ocean6, CCZ7

Received: 14 Oct 2024; Accepted: 19 May 2025.

Copyright: © 2025 Young, Webber, Karantzas, Miteva, Oakes, Santillo and Johnston. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Kirsten F. Young, Biosciences, Faculty of Health and Life Sciences, University of Exeter, Exeter, United Kingdom

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