Recent years have seen an increase in the number of green turtles nesting in Cyprus, but new research reveals that this recovery is primarily reliant on an Egyptian lagoon where many turtles graze.
An endangered species, green turtles spend the majority of their lives feeding in one location, yet they return to the beach where they gave birth to lay eggs.
The University of Exeter and the North Cyprus Society for the Protection of Turtles (SPOT) conducted a new study in which they monitored and tagged females that were laying eggs at important rookeries (breeding beaches) in Cyprus. They discovered that 74% of these females foraged at Lake Bardawil in Egypt.
The study discovered that the number of nests has virtually tripled since the early 1990s; nonetheless, turtle populations are vulnerable if conditions at a few feeding places, particularly Lake Bardawil, alter because of their reliance on it.
According to Dr. Robin Snape of the Centre for Ecology and Conservation at Exeter’s Penryn Campus in Cornwall, “from roughly 2010, our tracking of turtles from Cyprus has shown a significant rise in the number foraging at Lake Bardawil.”
“The number of adult turtles foraging around Cyprus and Turkey has decreased at the same time, presumably as a result of significant turtle bycatch (unintentional catch) in local fisheries.”
“The protection of nesting places in Cyprus and the circumstances at Lake Bardawil appear to be the main causes of the general increase in nest numbers.”
The lake may eventually fill to capacity, at which point the population growth of green turtles may halt.
Turtles and other marine animals can swim in and out of Lake Bardawil, a lagoon with a man-made outlet that leads to the ocean.
Although it was originally built as a fishery in the 1950s, adult green turtles—which can grow to be over a meter long and weigh more than 100 kilograms—now find it to be an excellent seagrass habitat.
The latest research tracked 19 female turtles that were nesting at significant rookeries on the Karpaz Peninsula in Cyprus using long-term satellite tagging.
One turtle traveled the longest journey ever recorded for a Mediterranean green turtle, traveling 1,500 miles (2,400 km) to the island of Djerba in Tunisia while the majority of the turtles headed to Lake Bardawil.
The average annual nest numbers grew from 186 to 554 when compared to the earliest three-year nest count averages (1993–1995) and nest counts conducted as part of this study (2017–2019).
According to Professor Annette Broderick of the University of Exeter, “Given the importance of Lake Bardawil for green turtles in the Eastern Mediterranean, it’s crucial that the ecosystem there be maintained in a way that protects turtles and promotes the lives of fishers.”
Green turtle populations could rise and depend less on this one place if bycatch is reduced and other habitats are protected, according to the report.
The MAVA Foundation and the Natural Environment Research Council provided funding for the study.
The article is titled “Mediterranean green turtle population recovery increasingly depends on Lake Bardawil, Egypt,” and it was published in the journal Global Ecology and Conservation.
