Lockdown measures eased the egg-laying of sea turtles in Greece but didn’t cause the observed increase of their nests
ARCHELON has been receiving enquiries from international organizations and nature documentary producers as early as April this year. The last two days many friends, researchers and journalists from Greece and abroad have been asking us about a possible relationship between the lockdown in Greece and the reproduction of loggerhead sea turtles in Greek nesting beaches. Here are the answers to their 4 most frequently asked questions, based on scientific evidence and data that ARCHELON has been collecting without fail since 1984.
Q- Has anything special and interesting been observed in the field this year, something measurably different from loggerhead nesting in previous years?
A- This year,ARCHELON researchers and volunteers have recorded over 1700 nests in Zakynthos, in collaboration with the National Marine Park, and in this respect, this year is the 3rd best year since 1984, when ARCHELON began to systematically record the nests. ARCHELON's long-term monitoring work has made clear that the number of nests fluctuates every year in Laganas Bay, Zakynthos, as is the case with most sea turtle populations in the world.
In Kyparissia Bay, ARCHELON recorded over 3500 nests at the core area of the nesting habitat, i.e. 9.5 km of beach from Kalo Nero to the estuary of Neda, more than any other year since 1984. Although there are annual fluctuations in this area as well, a significant upward trend in the number of nests has been recognized in the last decade.
Q- Can the observed increase in the number of nests recorded by ARCHELON in Zakynthos and in Kyparissia Bay be attributed to the lockdown?
A- The number of nests recorded each year is mainly related to the number of female turtles that reach the nesting beach. Loggerheads nesting in Greece spend their time in their feeding grounds, located mainly in the Gulf of Gabes (North Africa) and the North Adriatic, and every 2-3 years they migrate to the nesting beaches to lay their eggs. Whether and when a female turtle is ready to migrate from its feeding grounds to the nesting beach, depends on various factors. The most important factor is good nutrition, i.e. the storage of sufficient fat that will help it withstand the high energy costs of migration and reproduction, which last from about February to August.
The lockdown and travel restrictions due to COVID-19 were implemented in Europe and around the world in the spring of 2020, i.e. when sea turtles in the Mediterranean had already begun their reproductive migration to the nesting beaches in Greece and elsewhere. It is therefore unlikely that the restrictive measures drove more turtles to carry out this migration as they could not obtain the required energy reserves in such a short time.
Q- Do you mean that the absence of people from the beaches had no effect on the nesting of sea turtles?
A- ARCHELON’s scientific publications and observations all these years have indicated that females avoid going ashore when there are lights, loud noises or umbrellas and sunbeds, and usually select another part of the beach, with less disturbance. For this reason, special measures are adopted in the National Marine Park of Zakynthos and in the Nature Protection Area of Kyparissia Bay. Although the rate of implementation of these measures is higher in the National Marine Park of Zakynthos, violations of the law occur frequently.
In this respect, the conditions for nesting were ideal until the end of June this year because there was almost zero disturbance to the turtles. Therefore, the turtles that had reached the nesting beaches could lay eggs undisturbed. From July onwards, umbrellas and sunbeds appeared in specific parts of the nesting beaches in all the areas monitored by ARCHELON, which makes nesting somewhat difficult.
In conclusion, this years’ absence of human disturbances from nesting beaches, eased the egg-laying of sea turtles but didn’t cause the observed increase of nest numbers, as claimed by several articles that appeared recently in the press and do not have any scientific basis.
Q- Do you expect that the low tourist activity from July onwards will favor a higher number of hatchlings this year?
A- While the question seems simple, it is not. First of all, a high number of nests does not necessarily produce an equally high number of hatchlings. In the 37 years that ARCHELON has been collecting detailed data, there are some years when, even though a high number of nests had been laid, the hatching rate of the eggs was lower than that of other years with fewer nests. The hatching success for 2020 will be calculated after the nests hatch and the data on the number of hatchlings are processed.
But hatchlings are met with another problem on their way to the sea, that of light pollution. In all nesting areas in Greece there are points or even entire beaches where a huge effort is made by ARCHELON researchers and volunteers in order to save the hatchlings that are disoriented by the lights. This year's low tourist activity does not necessarily mean that the lights on the nesting beaches will be reduced. ARCHELON has already appealed to residents, businesses and visitors in all nesting areas, to turn down or turn off the lights after 11 pm until the end of September. This is for us the simultaneous challenge and opportunity of the COVID 19 summer.
- Giannis Chalkias, ARCHELON’s project officer for west Peloponnese, tel.: 6932285817, email: email@example.com
- Nikoletta Sidiropoulou, ARCHELON’s project officer for Zakynthos, tel.: 6982766371, email: firstname.lastname@example.org
Notes to editors:
ARCHELON The Sea Turtle Protection Society of Greece has been systematically monitoring and recording the reproductive activity of the loggerhead sea turtles in Laganas Bay in Zakynthos and Kyparissia Bay since 1984. Later, monitoring also began on the nesting beaches of Crete and southern Peloponnese (Lakonikos Bay, Romanos and Koroni). This has resulted in the development of one of the most comprehensive databases for the species in the world, which has helped us better understand the sea turtles’ biology and ecology in the Mediterranean.
See our recent post on the official ARCHELON facebook page with hatchings emerging from nest on Gerakas beach, Zakynthos: https://www.facebook.com/archelon.gr/videos/1952374221563053/
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