The numbers of two species of Mediterranean sea turtle have increased over the past three decades – but recovery is happening at different rates in Cyprus, new research shows.
The number of nests on 28 beaches shows that green turtle nests increased 162% from 1993 to 2019, while loggerhead carp nests increased 46%.
The research team – from the University of Exeter, the Society for the Protection of Turtles (SPOT), and Eastern Mediterranean University – says the difference is likely due to higher death rates in loggerhead turtles of all ages.
In the past turtles were hunted for meat and mussels in this region, today this is forbidden in the entire Mediterranean area. Coupled with the maintenance of the breeding beaches, populations have recovered – but scientists say better protection at sea is still needed.
“The recovery of these populations is very encouraging,” said Dr. Lucy Omeyer from the Center for Ecology and Conservation on Exeters Penryn campus in Cornwall.
“However, the different recovery rates suggest that loggerheads are facing additional threats compared to those exposed to green turtles.
“The adult green turtle seagrass diet may explain this in part, as green turtles are less likely to be caught as bycatch (accidental catch by fishermen) as they live most of their lives in very specific habitats that are also protected.
“Green turtles are also more likely than loggerheads to return to the same breeding beaches and stay close to the beach, while loggerhead carp roam around fishing grounds during the breeding season.”
The study found “stable” reproduction rates in loggerheads, suggesting that deaths in turtles of all ages (rather than lack of juveniles) “hamper the recovery of this species.”
Dr. SPOT’s Damla Beton said, “Our other studies have shown that many adult loggerheads die in the fishery when visiting Cyprus to breed, as well as in foraging areas across the region.
“So it’s not surprising that this mortality is reflected in nesting trends.
Despite the recovery of green turtles, their total population in the Mediterranean is estimated to be only 3,400 adults, while their main breeding and feeding grounds are limited to a handful of locations.
The study was supported by the North Cyprus Ministry of the Environment.
The paper published in the magazine Animal welfare , is entitled, “To study the differences in the population recovery rate of two sympatric nesting sea turtle species.”