Europe's high court has ruled that Greece has failed to protect an important nesting site for the loggerhead sea turtle. Nesting sites are of utmost importance, since loggerhead breeding is infrequent and precarious.
Image: Imago/Nature Picture Library
Advertisement
Rough start to life for the loggerhead sea turtle
This species is considered vulnerable in the Mediterranean, in part because its breeding process is infrequent and precarious. So it doesn't help when people build bars adjacent to nesting areas.
Image: picture-alliance/AA/S. Elcin
A loggerhead's life
This sea turtle spends most of its life in saltwater and estuarine habitats, with females briefly coming ashore to lay eggs.
Image: cc by ukanda 2.0
Making landfall
Loggerhead turtles are amazing creatures - but the are also vulnerable, in part because they only lay eggs once every two to three years.
Image: Imago/Nature Picture Library
Back to the sea
After they lay their eggs, the female turtles return to the water.
While they are incubating, the eggs are vulnerable to predators and human incursion.
Image: picture-alliance/AA/S. Elcin
New life
If the egg survives the incubation period, a baby loggerhead is born.
Image: Imago/Nature Picture Library
Dangerous journey
The baby turtle must then make a treacherous journey to the sea, surviving predators along the way. Loud noises from human activity can cause them to get lost.
Image: picture-alliance/dpa/Katia Christodoulou
Almost there
A large number of hatchlings die during the journey to the sea. Those that reach the water can grow to be adults - if they don't starve in their first days.
Image: picture-alliance/AA/S. Elcin
Facing threats
Also as adults, loggerheads face numerous threats in the sea. This loggerhead has been fitted with a prosthetic titanium beak after being mutilated in a boating collision.
Image: picture alliance/abaca/K. Gurbuz
8 images1 | 8
The European Court of Justice, the "supreme court" of the European Union, ruled on Thursday (10.11.2016) that Greece has failed to protect loggerhead sea turtles that lay their eggs in the Bay of Kyparissia.
The bay is protected under the EU's Natura 2000 network, which designates areas that cannot be disturbed because they contain endangered species. But according to the court's ruling, Greek authorities have allowed homes and roads to be built in the area over the past 20 years.
Kyparissia Bay in Greece is the second-most-important breeding ground for loggerhead turtles in the MediterraneanImage: Estelle Angelinas
"The construction and use of such infrastructure, particularly because of the noise, light and human presence entailed, are likely - as are 'wild' camping and the operation of bars - to significantly disturb the loggerhead turtle during breeding," the court said in a statement.
The bay is the second-most-important breeding site for the loggerhead sea turtle, which only lays eggs once every two to three years.
Female sea turtles, which are on average 90 centimeters long, leave the sea at night and move towards the driest area of the beach, where they dig a hole, into which each lays around 120 eggs.
Two months later, the eggs hatch and the young turtles emerge from the sand, heading toward the sea. Because they are vulnerable, a large number of the hatchlings die. For this reason, the turtle has a low reproductive rate.
The loggerhead sea turtle is also found in the Atlantic, Pacific, and Indian oceans. It spends most of its life in saltwater and estuarine habitats, with females briefly coming ashore to lay eggs.
Loggerheads are among the most common species to be held in captivityImage: picture-alliance/dpa/J. Büttner
In addition to disruption of breeding grounds, untended fishing gear is also responsible for many loggerhead deaths. Turtles may also suffocate if they are trapped in fishing trawls. Loggerhead turtles, along with green sea turtles, are the sea turtle species that are most commonly kept in captivity.
The European Commission, the EU's executive branch, first brought a complaint against Greece for failing to protect the turtles in 2011. Since it was not satisfied with the country's response, it took Greece to court.
The court has ruled in the past that Greece was failing to protect sea turtles elsewhere in the country, on the Ionian island of Zakynthos.
The ruling in the Kyparissia Bay case is more serious, because the court found that the regional authorities had no "comprehensive and coherent preventive legislative framework" in place before the commission brought it to court.
However, the court recognized that some legislative action was taken by Greece after the complaint was brought, to prevent further construction.
If Greece fails to limit development around the bay to protect the turtle's habitat, the commission can ask the court to impose fines.
The sea turtles' compass
How do sea turtles return back to their home beach for nesting? They instinctually orientate themselves using the Earth's magnetic field. Now, scientists have learned more about how this works.
Image: Robert Harding
Compass included
Loggerhead turtles use the Earth's magnetic field as a compass. They memorize the patterns of the home beach when they were born, a new study in "Current Biology" says.
Image: Robert Harding
Keen instinct for Earth's magnetism
With help of their magnetic sense, sea turtles return back to their birth beach once they are about 12 years old. Even though their journey starts thousands of miles away, they perceive the intensity and angle of inclination of the Earth's magnetic field lines. These two factors vary regionally - different sections of coast have different magnetic patterns.
Image: picture-alliance/dpa/S. Sauer
Not only turtles
Also other animals have that sense for magnet fields: pigeons, migratory birds, crabs and even dogs or cows can perceive such patterns. Fascinating fact: Cows graze their pasture in a specific direction due to the magnetic field there.
Image: M. Abdollahi
Ultimate test
But what if the magnetic field undergoes slight variation? Researchers at the University of North Carolina analyzed exactly that from 1993 to 2011 along Florida's coast. They found a correlation between the changes in magnetic field and distribution of sea turtle nests. Depending on fluctuation, nesting areas moved closer together, or other times were spread further apart.
Image: picture-alliance/dpa/Katia Christodoulou
Finding a safe place
The study did not imply that the turtles lay their eggs automatically in the exact spot where they were born. Many other factors - such as temperature, sand quality or accessibility of the beach - were also involved in choosing a nesting site, the researchers wrote.
Image: picture-alliance/dpa/S. Sauer
Invisible to us
The Earth's magnetic field originates from electrical currents in metal alloys in the Earth's core. We humans don't have that fine sense of being able to sense this magnetic field - yet we are certainly keen to understand it! The European Space Agency's Swarm mission in 2014 began delivering the highest-resolution-ever images of the Earth's magnetic field.
