[MARMAM] New publication: Spatial Distribution and Encounter Rates of Delphinids and Deep Diving Cetaceans in the Eastern Mediterranean Sea of Turkey and the Extent of Overlap With Areas of Dense Marine Traffic

Tim Awbery tim.awbery91 at gmail.com
Wed Jul 20 08:00:55 PDT 2022

Dear MARMAM community,

On behalf of my co-authors, I am delighted to share that our manuscript has
recently been published in Frontiers in Marine Science:

Awbery, T., Akkaya, A., Lyne, P., Rudd, L., Hoogenstrijd, G., Nedelcu, M.,
Kniha, D., Erdoğan, M.A., Persad, C., Amaha Ozturk, A. and Öztürk, B.
(2022). Spatial Distribution and Encounter Rates of Delphinids and Deep
Diving Cetaceans in the Eastern Mediterranean Sea of Turkey and the extent
of overlap with areas of dense marine traffic. Frontiers in Marine Science,
*9:860242*. https://doi.org/10.3389/fmars.2022.860242


Marine traffic has been identified as a serious threat to Mediterranean
cetaceans with few mitigation strategies in place. With only limited
research effort within the Eastern Basin, neither baseline species
knowledge nor the magnitude of threats have been comprehensively assessed.
Delineating the extent of overlap between marine traffic and cetaceans
provides decision makers with important information to facilitate
management. The current study employed the first seasonal boat surveys
within the Eastern Mediterranean Sea of Turkey, incorporating visual and
acoustic survey techniques between 2018 and 2020 to understand the spatial
distribution of cetacean species. Additionally, marine traffic density data
were retrieved to assess the overlap with marine traffic. Encounter rates
of cetaceans and marine traffic density were recorded for each 100
km<sup>2</sup> cell within a grid. Subsequently, encounter and marine
traffic density data were used to create a potential risk index to
establish where the potential for marine traffic and cetacean overlap was
high. Overall, eight surveys were undertaken with a survey coverage of
21,899 km<sup>2</sup> between the Rhodes and Antalya Basins. Deep diving
cetaceans (sperm and beaked whales) were detected on 28 occasions, with 166
encounters of delphinids of which bottlenose, striped and common dolphins
were visually confirmed. Spatially, delphinids were distributed throughout
the survey area but encounter rates for both deep diving cetaceans and
delphinids were highest between the Rhodes and Finike Basins. While sperm
whales were generally detected around the 1000m contour, delphinids were
encountered at varying depths. Overall, two years of monthly marine traffic
density were retrieved with an average density of 0.37 hours of monthly
vessel activity per square kilometer during the study period. The mean
density of vessels was 0.32 and 1.03 hours of monthly vessel activity per
square kilometer in non-coastal and coastal waters respectively. The
Eastern Mediterranean Sea has several important shipping lanes within the
study area. Two priority areas for deep diving cetacean and a large
priority area for cetaceans were identified in the waters between Marmaris
and Finike where high cetacean encounters and dense marine traffic
overlapped. The current study revealed important habitats for cetaceans
within the data deficient Eastern Mediterranean Sea and delineated
potential risk area where marine traffic should be limited.

I would like to add that the people that have made this project happen
extend far beyond the authors listed here, and we would like to thank all
of the volunteers, captains and crew that have been involved in the survey
effort  and all of the other individuals that have been on hand to offer
advice in one form or another.

The full article is open access, and available online:


Best wishes,

Tim Awbery

PhD Researcher

SAMS Marine Mammals Research Team

Scottish Association for Marine Science, Oban, Argyll, PA37 1QA

tim.awbery at sams.ac.uk
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