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ORIGINAL RESEARCH article

Front. Mar. Sci.
Sec. Ocean Observation
Volume 11 - 2024 | doi: 10.3389/fmars.2024.1425259

Development and operation of a novel non-invasive opto-acoustic Underwater Fish Observatory in Kiel Bight, Southwestern Baltic Sea

Provisionally accepted
Joachim P. Gröger Joachim P. Gröger 1,2Boris Cisewski Boris Cisewski 1*Sabah Badri-Hoeher Sabah Badri-Hoeher 3Gordon Böer Gordon Böer 4Karin Boos Karin Boos 5Catriona Clemmesen Catriona Clemmesen 2Ala Cojocaru Ala Cojocaru 6Verena Dauben Verena Dauben 7Peter A. Hoeher Peter A. Hoeher 8Andreas Lehmann Andreas Lehmann 2Sebastian Matz Sebastian Matz 9Hela Mehrtens Hela Mehrtens 2Felix Mittermayer Felix Mittermayer 2Helge Renkewitz Helge Renkewitz 9Hauke Schramm Hauke Schramm 4,8Tobias Strickmann Tobias Strickmann 2Jonni Westphalen Jonni Westphalen 3Thomas Wilts Thomas Wilts 3Julian Winkler Julian Winkler 3Dennis Wolf Dennis Wolf 7Oliver Zenk Oliver Zenk 7
  • 1 Thünen Institute of Sea Fisheries, Bremerhaven, Germany
  • 2 GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
  • 3 Institute of Communications Technology and Microelectronics, Kiel University of Applied Sciences, Kiel, Germany
  • 4 Institute of Applied Computer Science, Kiel University of Applied Sciences, Kiel, Germany
  • 5 City University of Applied Science, Bremen, Germany
  • 6 Phi-Stone AG, Kiel, Germany
  • 7 MacArtney Germany GmbH, Kiel, Schleswig-Holstein, Germany
  • 8 Faculty of Engineering, University of Kiel, Kiel, Schleswig-Holstein, Germany
  • 9 Fraunhofer IOSB, IOSB-AST Ilmenau, Fraunhofer Institute of Optronics, System Technologies and Image Exploitation, Ilmenau, Germany

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

    This study presents a trilateral test array of new opto-acoustic Underwater Fish Observatories (UFOs) that were operated and tested in Kiel Bight as part of the "UFOTriNet" project. While hydroacoustic and optical techniques have so far been used individually to observe and monitor fish stocks, we present a coupled hybrid system consisting of an optical device intended to scan the near-field as a subsample of a spatially larger medium-to-far-field, scanned by an acoustical device. The optical device consists of two residual light amplifying camera modules able to detect and classify various marine species at a high resolution in the range of at max 4 meters in the study area. To compensate for this spatial limitation, the acoustical component consists of a 2D imaging sonar with a maximum range of 50 m, albeit with a lower resolution. Species affiliation, morphometric characteristics of fish and other marine organisms were stereo-optically detected and classified in the nearfield, blended with acoustical activity in medium to far range, and projected onto the entire insonified area using a hybrid algorithm. Through the synchronous acquisition of multiparametric abiotic and biotic data, UFO allows an automatic, continuous, and non-invasive long-term monitoring of various fish and other marine species and their habitats at regional hotspots. An 86-day multiparametric sample revealing an abrupt shift from a clupeid fish to a gelatinous plankton dominated regime in summer / autumn 2021 in Kiel Fjord is used to demonstrate the potential of UFO for various applications.

    Keywords: UFOTriNet, Automated Fish Classification, remote ecosystem monitoring, automated noninvasive fish monitoring, Fish community, Southwestern Baltic Sea

    Received: 29 Apr 2024; Accepted: 29 Jul 2024.

    Copyright: © 2024 Gröger, Cisewski, Badri-Hoeher, Böer, Boos, Clemmesen, Cojocaru, Dauben, Hoeher, Lehmann, Matz, Mehrtens, Mittermayer, Renkewitz, Schramm, Strickmann, Westphalen, Wilts, Winkler, Wolf and Zenk. 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: Boris Cisewski, Thünen Institute of Sea Fisheries, Bremerhaven, Germany

    Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.