Sea turtles commence egg-laying prior to expected dates.

Weather in Greece - Early egg-laying observed in sea turtles

A loggerhead sea turtle named Caretta caretta can be seen laying its eggs on the western coast of Greece annually. However, this year, the organization Archelon, which specializes in protecting sea turtles, found a nest of this endangered species on the island of Zakynthos earlier than usual. This could be a sign of changing environmental conditions.

Female sea turtles crawl up to the shore at night to lay their eggs, returning to the same spot they hatched from their eggs 30 years ago. The animals reach sexual maturity at 35 to 39 years old, and their shells grow up to 100 centimeters, weighing as much as 110 kilograms. These turtles laboriously dig holes, deposit around 100 eggs, cover them with sand, and then retreat into the sea. In Greece, this annual event can be observed exceptionally early this time.

Archelon Research Coordinator, Aliki Panagopoulou, shared that this is the first time they discovered a nest so early in May in Laganas Bay on Zakynthos in their records. Just a few days later, they found the first nests on the west coast of the Peloponnese peninsula and northern Crete - both of which were also laid earlier than usual.

"Scientists anticipated in 2016 that the nesting season would change due to climate change," explains Panagopoulou. Sea turtles are extremely sensitive to environmental changes, and their breeding season starting earlier suggests that the turtles are adapting to avoid high summer temperatures. According to the European Climate Report 2023, the average sea surface temperature last year was higher than it's ever been since records began - reaching up to 5.5 degrees above the average value in some places.

The fact that turtles are laying eggs earlier is not too concerning, Panagopoulou notes, but the consequences of heat on the hatchlings are catastrophic. "Higher temperatures in the nest can impact the sex of the offspring. In the future, this change may lead to the demise of the entire population because females would struggle to find males to mate with due to an inequality in the sex ratio."

Hatchlings already face various dangers. When they hatch, they have to walk across the beach to reach the sea. Predatory animals like seagulls and fish are threats, and only a few (very few) of the 1000 hatchlings that emerge reach a reproductive age.

Moreover, environmentalists face more challenges to protect these turtles. Noise from onlookers often causes the mothers to flee the beach, and they abandon their nests. The nests must also be guarded to keep them from being trampled or dug up by dogs. Acts of kindness such as carrying hatchlings into the sea can actually be harmful. The journey across the sand strengthens these newborns.

The primary hazards include environmental pollution, shipping, water sports, and fishing. For example, turtles can get caught in fishing nets.

The organization Archelon, which has been operating for over 40 years, has made progress in protecting these turtles by marking and safeguarding breeding sites. "Most of the sea turtle populations in Greece are now stable or even thriving, like on Crete," Aliki says.

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Environmentalists have expressed concern over the early egg-laying of hawksbill turtles, a type of sea turtle, along the west coast of Greece. This phenomenon was observed in Zakynthos, Greeces's famous turtle nesting site, and has been linked to climate change.

Archelon, an organization dedicated to protecting sea turtles in Greece, has noted an increasing trend of early egg-laying among sea turtles, including the hawksbill turtle. This shift is thought to be a response to rising sea surface temperatures, as predicted by scientists in 2016.

The changing environment and earlier egg-laying could have significant consequences for the hawksbill turtle population, according to Aliki Panagopoulou, Archelon's Research Coordinator. Higher temperatures in the nests could impact the sex ratio of hatchlings, potentially leading to a demise of the population due to an imbalance in the male-female ratio.

The early egg-laying has also made it more challenging for environmentalists to protect these endangered animals. Nests are more susceptible to tampering, and mothers are more likely to abandon their eggs due to disturbances on the beach.

As temperatures continue to rise due to climate change, environmentalists are working to adapt their conservation efforts for hawksbill turtles. This includes educating the public about the importance of maintaining quiet surroundings during nesting seasons and implementing measures to protect these vulnerable turtles from human-induced threats like pollution, shipping, and fishing.

Further research is necessary to understand the long-term effects of climate change on hawksbill turtle populations on the Greek coast. Scientists are closely monitoring the nesting patterns and hatching rates of these sea turtles to better understand how they are adapting to changing environmental conditions.

Climate change is not the only threat to hawksbill turtles. worldwide, these reptiles are listed as critically endangered, mainly due to poaching and habitat destruction. Environmental organizations in Greece and internationally are working together to combat illegal hunting and conserve critical habitat for hawksbill turtles and other sea turtles.

The Athens Zoo participates in hawksbill turtle conservation efforts, housing and breeding the species in captivity for release into the wild on the Greek coast. The zoo also educates visitors about the importance of protecting sea turtles and their habitats to help ensure a future for these iconic animals.

Source: www.stern.de