Vol. 61, 2022
Abundance Trends and Nesting
Biology of Green Turtles Chelonia mydas (Testudines: Cheloniidae)
During Ten Consecutive Breeding Seasons at Akyatan Beach, Turkey
Can Yılmaz1,2,*, Ayşe Oruç2, and Oguz Turkozan3,4
School of Health Services, Hakkâri University, Keklikpınar Mahallesi
Kampüs Caddesi 30000 Hakkâri, Turkey. *Correspondence: E-mail:
2WWF Turkey, Buyuk Postane Caddesi No:19 Kat 5, 34420 Bahcekapi, Eminonu, Istanbul, Turkey. E-mail: email@example.com (Oruç)
of Biology, Faculty of Science and Arts, Aydın Adnan Menderes
University, 09010 Aydın, Turkey. E-mail: firstname.lastname@example.org
4Cyprus Wildlife Research Institute, Kyrenia, Northern Cyprus, Research Associate, Cyprus
Received 21 February 2022 / Accepted 25 June 2022
Communicated by Yoko Nozawa
obtained from long-term survey studies are valuable for assessing the
population status and trends in critical populations of threatened
species, like sea turtles. Akyatan beach is one of the most important
green turtle nesting beaches in the Mediterranean and has been
monitored since 2006 without interruption. The beach is 22 km long and
more than 100 m wide at some points, and both loggerhead and green
turtles nests on the beach. However, the loggerhead nesting is very
limited in comparison to green turtles. A total of 3866 C. mydas
nests were recorded during ten consecutive years at Akyatan beach, with
a mean of 387 ± 127 nests (range = 201–559). The average nesting
density was 17.6 nests km-1 (range = 9.1–25.4 nests km-1).
In the 3309 nests, a total of 355,259 eggs were counted. The overall
mean clutch size was 112 ± 26.10 eggs. Of these eggs, 50.80% hatched
(depredated nests included), and 78.07% of them were able to reach the
sea. The overall mean hatching success was 73.07 ± 26.20%. The overall
mean incubation duration was 51.4 ± 3.5 days. The clutch sizes and
hatching success differed between years, and there was a significant
trend in mean incubation duration to decrease over ten years of study.
A total of 1585 green turtle nests (41.02% of nests) were totally or
partially depredated by golden jackals and wild boar, while other
predators depredated 20.5% of hatchlings. The nesting data obtained
since 2006 showed strong annual fluctuations ranging from 170 (in 2007)
to 562 (in 2006) with a slightly increasing but statistically
insignificant trend (r = 0.94, p > 0.05). The main threats to the population were depredation by jackals and wild boars.
Key words: Endangered species, Conservation, Sea turtles.
Citation: Yılmaz C, Oruç A, Türkozan O. 2022. Abundance trend and nesting biology of green turtles Chelonia mydas (Testudines: Cheloniidae) during ten consecutive nesting seasons at Akyatan Beach, Turkey. Zool Stud 61:53.