General Information About Sea Turtles

Sea Turtles

Sea turtles, often referred to as “living fossils,” have been around for approximately 120 million years*, playing a pivotal role in marine and coastal ecosystems. Despite their ancient lineage, all seven existing species have faced endangerment since the mid-1900’s, primarily due to human activities.

*Desmatochelys padillai (Cadena, E.A. and J.F. Parham. 2015. Oldest known marine turtle? A new protostegid from the Lower Cretaceous of Colombia. PaleoBios32.)

Species and Habitats
Sea turtles predominantly inhabit the ocean throughout their lives, but they come to beaches to lay their eggs. Some of the most significant nesting sites for loggerhead sea turtles (Caretta caretta) and green sea turtles (Chelonia mydas) can be found along the Mediterranean coast of Türkiye.
Typically, only females come to the beaches, but on rare occasions, males can also be observed on the shores. Male and female sea turtles share a general similarity in appearance and size. However, males can be easily distinguished with their long tails.
There are seven sea turtle species in the world and they all exhibit distinct feeding preferences, encompassing a range of options within their diets. Generally, their food sources may include algae, aquatic plants, jellyfish, sea urchins, anemones, mollusks, crustaceans, and various fish species.


Mating and Nesting
The process of mating occurs several weeks before the nesting begins, near the nesting beaches or in designated gathering areas. Mating sea turtles can often be seen on the water’s surface, although underwater mating is also common. Nesting season in the Northern Hemisphere generally lasts from May to August. They lay their eggs primarily during the nighttime, although daytime nesting can occasionally be observed.
Nearing the beach to lay her eggs, the female sea turtle is highly sensitive to external stimuli. After depositing her eggs, she covers them with damp sand, and compact it securely. The female then returns to the sea, camouflaging her nest. Sea turtles generally nest every 2-3 years, and may nest more than once in the same season.


Incubation Period and Hatchlings
Newly laid sea turtle eggs are typically spherical, white, soft, and coated with mucus. Each nest contains approximately 100 eggs, with an incubation period lasting between 1.5 to 2 months. At the end of this period, hatchlings emerge by breaking through their shells and typically leave the nest within an average of 5 days. Guided by the horizon’s light, hatchlings make their way towards the sea. Artificial light sources behind the beach can lead to their disorientation and, tragically, result in fatalities.
Sea turtles play a crucial role in the ecosystem, contributing to the balance of marine and coastal environments. In the sea, they regulate populations of their prey species (jellyfish, crustaceans, sponges, etc.) by curbing their excessive growth, and plant-feeding species contribute to the health of seagrass meadows by “mowing” them, aiding in their healthy development. On land, sea turtles enrich sandy beaches, which are typically nutrient-poor habitats, by providing an influx of minerals through the eggshells they lay. Conscious efforts are essential to protect these magnificent creatures, which face endangerment due to human activities.



The Threatened Lives of Sea Turtles
Despite surviving in the world’s waters for millions of years, sea turtles face severe threats due to escalating human activities since the mid-1900’s. These precious creatures have become endangered due to being hunted for their meat, shells, skin, and oil, alongside poaching of their eggs for consumption. Unconscious management of coasts and the seas, pollution on land and in the sea, and fishing practices intensify this situation.
Every year, thousands of sea turtles drown because of shrimp nets, trawls, and hooked fishing lines. The marine environment poses significant hazards for both young and adult sea turtles. Boat accidents and propellers can cause injuries and fatalities, while natural predators such as killer whales, sharks, birds, and fish further threaten their existence. Marine pollution, particularly plastic waste mistaken for food, can damage their internal organs, leading to death, or impede health by hindering nutrient absorption. On land, sea turtle hatchlings face predation from natural predators such as foxes, badgers, seagulls, gulls, raccoons, carrion crows, and ghost crabs, while increasing numbers of dogs exacerbate predation rates.
Breeding grounds of sea turtles, namely beaches, are gradually diminishing due to factors like climate change, marine debris, coastal development, erosion, and tourism pressure. Human activities, particularly coast guarding activities and night lights, adversely impact the breeding process. To ensure the survival of these species, it is crucial to implement diverse conservation efforts in breeding, feeding, wintering, and migration areas. Sustaining conservation efforts and controlling human activities are paramount for the continued survival of these remarkable animals.