BRIEF RESEARCH REPORT article
Front. Mar. Sci.
Sec. Deep-Sea Environments and Ecology
Volume 12 - 2025 | doi: 10.3389/fmars.2025.1666456
Deep-sea sedimentary cave structures: Geology or fish-made?
Provisionally accepted
- 1Bergverk AS, Sandefjord, Norway
- 2Aker BP ASA, Lysaker, Norway
- 3Department of Earth Science, Center for Deep Sea Research, University of Bergen, Bergen, Norway
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At the Central Mohns Ridge, numerous large cave-like structures were observed in deep-sea sediments at approximately 1200 and 1600 m depth. The glacial eelpout (Lycodes frigidus) was found inhabiting some of these caves, with one individual observed guarding a clutch of eggs. This paper examines the origin of these structures, questioning the hypothesis put forward previously that they are formed by geological processes such as catastrophic fluid vent escapes. No significant disruption of the sedimentary layering was observed, and the caves have a semi-horizontal orientation and are of limited size. We propose that these caves are actively excavated or modified by fish for habitation and protection, a behavior documented in other zoarcids and in other fish families. This observation represents, to our knowledge, the first documented case of parental care by egg guarding inside a cave for L. frigidus.
Keywords: Lycodes frigidus, Zoarcidae, deep-sea caves, parental care, predator avoidance, Burrowing behavior, Fluid escape, Bio-construction
Received: 15 Jul 2025; Accepted: 03 Sep 2025.
Copyright: © 2025 Marnor, Souche, Hartz, Jæger and Schmid. 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: Camilla Mult Marnor, Bergverk AS, Sandefjord, Norway
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