Turtles have inhabited our planet for over 200 million years. Dating back to the early ages of the dinosaurs, turtles have followed a unique and successful evolutionary path that has allowed them to thrive on our planet. Scientists have classified sixteen different orders of reptiles that have evolved in the last 310 million years. The turtles, or Testudines, are one of only four orders that have evolved in such away that they flourish in present time.
There are currently seven recognized species of sea turtles:
Loggerhead (Caretta caretta)
Green (Chelonia mydas)
Leatherback (Dermochelys coriacea)
Hawksbill (Eretmochelys imbricata)
Kemp’s ridley (Lepidochelys kempii)
Olive ridley (Lepidochelys olivacea)
Flatback (Natador depressa)
Sea turtles are air breathing reptiles that live in marine waters. They are distinguished from land tortoises and fresh water turtles by their large flippers and streamlined bodies which enable them to be exceptional swimmers. Their bodies consist of a hard bony or a thick leathery shell that provides some protection to their soft inner body and sensitive organs. Unlike their closest turtle relatives, sea turtles cannot pull their limbs or head into their shell. This makes them more susceptable to predators. Sea turtles have powerful jaws which are useful for crushing food and sometimes for defending themselves. Most species have a thick beak like jaw adapted for crushing hard foods. The Green sea turtle in contrast has a serrated beak that allows it to easily tear seagrasses and algae. The sea turtle species' can be identified from each other visually in five ways; (1) their shell type (2) the number and shape of scutes (bony plates) on their shell (3) the number and shape of scales on their head (4) shell measurements and (5) the number and location of claws on their flippers.
Aside from nesting, sea turtles spend their entire lives in the ocean. Each species has an area that they tend to frequent based on their food sources. These habitats range from coral reefs, bays, lagoons, benthic bottoms, nearshore and offshore waters. The only time healthy sea turtles come ashore is to lay eggs.
Throughout their lives sea turtles migrate from nesting areas to feeding grounds, which are sometimes several thousand miles away. Most turtles migrate along the coasts, but some populations are known to migrate across the ocean. As a species that migrates long distances, these turtles face special problems associated with differing attitudes toward conservation in different countries.
Sea turtles are amazing creatures when it comes to reproduction. They reach sexual maturity between 15-30 years of age. At this point they make a breeding migration to the area they initially hatched from. Female sea turtles will come ashore, generally during the night, to lay 5-8 clutches of eggs each nesting season. When she is ready, she will find a suitable spot above the high tide line to dig a teardrop shaped hole in the sand. Here she will deposit 50-200 eggs depending on the species. Incubation periods range between 45 and 60 days dependent on the temperature of the sand. Temperature will also determine whether the hatchlings will be male or female. Once ready, hatchlings emerge from the nest cavity and make their sea finding journey. It is said that only 1 in 1,000 hatchlings will survive to adulthood. This is due to many threats they face such as predation both on land and in the water, lighting disorientations, beach obstacles, and intensified storm and tidal activity.
Five of the world’s eight remaining sea turtle species - the loggerhead, green, leatherback, hawksbill, and Kemp’s ridley - may be found in Florida's coastal waters. Four of these species are classified as endangered in Florida by both federal and state governments; while the fifth species, the loggerhead, is listed as threatened.
Each year, female sea turtles crawl onto the County's beaches to lay their eggs in the loose dune sands. Several types of human activities can interfere with nesting activity and the ability of hatchlings to find their way into the Gulf. Artificial lighting disorients the hatchlings that depend upon the illuminated horizon for direction. Night pedestrian traffic can cause adult turtles to return to the ocean without nesting. Coastal development and beach nourishment activities that compact the sands can be equally detrimental. To address these problems, Charlotte County adopted a Sea Turtle Protection Ordinance (Ordinance 89-31)
which provides standards and criteria for coastal development, obstructions on the beach such as beach furniture, and restrictions for artificial lights visible from the nesting zone during the nesting season.