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ORIGINAL RESEARCH article

Front. Mar. Sci.
Sec. Marine Biology
Volume 11 - 2024 | doi: 10.3389/fmars.2024.1459029

Producing Local Bottlenose Dolphin Abundance Estimates to Fill Species Knowledge Gaps in the Eastern Mediterranean Surrounding Türkiye

Provisionally accepted
Aylin Akkaya Aylin Akkaya 1*Ceyda Ozdemir Ceyda Ozdemir 1Leyla Israpilova¹ Leyla Israpilova¹ 1Suzanne Kamsteeg Suzanne Kamsteeg 1Atakan Dalkılıç Atakan Dalkılıç 1Tim Awbery Tim Awbery 1,2
  • 1 Marine Mammals Research Association, Antalya, Türkiye
  • 2 Scottish Association For Marine Science, Oban, United Kingdom

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

    The Mediterranean subpopulations of bottlenose dolphins have recently been upgraded to least concern. Although large scale surveys indisputably provide crucial information on the population status of a species, they represent a snapshot in time. On the other hand, whereas local efforts may be less useful for basin-wide conservation, they often have increased effort and replicated surveys allowing more robust estimation and the ability to monitor population trends. The current study used a standard line transect survey design during 19 dedicated surveys conducted between April 2018 and June 2023 to provide local abundance estimates of bottlenose dolphin in the Eastern Mediterranean Sea surrounding Türkiye. The research boat covered 23,842 km with a survey coverage of 32,488 km 2 across a total of 167 days. Overall, 92 encounters of bottlenose dolphins were recorded, 43 of which took place whilst the vessel was 'on-effort', with a mean group size of four. While there were differences between the observed and expected sighting rates across different survey seasons, there was no clear pattern in the variation across years. Bottlenose dolphins were encountered most frequently towards the easternmost boundaries of Türkiye, but their distribution extended through both coastal and deep-sea waters across to the easternmost extension of Rhodes Basin, where the species was encountered up to 4000 m depth. The corrected abundance estimate of bottlenose dolphins was 2037±518 individuals (CV=0.25, 95% CI ) for the Eastern Mediterranean Sea of Türkiye and varied considerably from previous estimates for the area conducted at a basin-wide level. The local population estimates produced by this study extend our understanding of the status of bottlenose dolphins in the Eastern Mediterranean and are likely to contribute to basin-wide estimations.

    Keywords: delphinid1, design-based approach2, distance sampling3, encounter rates4, Levantine basin5, population size6, spatial distribution7, Tursiops truncatus8

    Received: 03 Jul 2024; Accepted: 12 Nov 2024.

    Copyright: © 2024 Akkaya, Ozdemir, Israpilova¹, Kamsteeg, Dalkılıç and Awbery. 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: Aylin Akkaya, Marine Mammals Research Association, Antalya, Türkiye

    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.