An Overview



Sea turtles are large, air-breathing reptiles that inhabit tropical and subtropical seas throughout the world. Their shells consist of an upper part (carapace) and a lower section (plastron). Hard scales (or scutes) cover all but the leatherback, and the number and arrangement of these scutes can be used to determine the species.

Sea turtles come in many different sizes, shapes and colors. The olive ridley is usually less than 100 pounds, while the leatherback typically ranges from 650 to 1,300 pounds! The upper shell, or carapace, of each sea turtle species ranges in length, color, shape and arrangement of scales.

Sea turtles do not have teeth, but their jaws have modified "beaks" suited to their particular diet. They do not have visible ears but have eardrums covered by skin. They hear best at low frequencies, and their sense of smell is excellent. Their vision underwater is good, but they are nearsighted out of water. Their streamlined bodies and large flippers make them remarkably adapted to life at sea. However, sea turtles maintain close ties to land.

Females must come ashore to lay their eggs in the sand; therefore, all sea turtles begin their lives as tiny hatchlings on land.

Reproduction

Only females come ashore to nest; males rarely return to land after crawling into the sea as hatchlings. Most females return to nest on the beach where they were born (natal beach). Nesting seasons occur at different times around the world. Most females nest at least twice during each mating season; some may nest up to ten times in a season. A female will not nest in consecutive years, typically skipping one or two years before returning.

Growth & Development

Researchers do not yet know how long baby turtles spend in the open sea, or exactly where they go. It is theorized that they spend their earliest, most vulnerable years floating around the sea in giant beds of sargasso weeds, where they do little more than eat and grow. Once turtles reach dinner-plate size, they appear at feeding grounds in nearshore waters. They grow slowly and take between 15 and 50 years to reach reproductive maturity, depending on the species. There is no way to determine the age of a sea turtle from its physical appearance. It is theorized that some species can live over 100 years.

Major ecological effects of sea turtle extinction

Sea turtles, especially green sea turtles, are one of the very few animals to eat sea grass. Like normal lawn grass, sea grass needs to be constantly cut short to be healthy and help it grow across the sea floor rather than just getting longer grass blades. Sea turtles and manatees act as grazing animals that cut the grass short and help maintain the health of the sea grass beds. Over the past decades, there has been a decline in sea grass beds. This decline may be linked to the lower numbers of sea turtles.

Sea turtles are part of two ecosystems, the beach/dune system and the marine system. If sea turtles went extinct, both the marine and beach/dune ecosystems would be negatively affected. And since humans utilize the marine ecosystem as a natural resource for food and since humans utilize the beach/dune system for a wide variety of activities, a negative impact to these ecosystems would negatively affect humans.

Why the population is getting decreased?

  1. The most damaging are the nets used in fishing. If caught, turtles are unable to come to the surface to breathe and they will suffocate.
  2. Coral mining and illegal methods of fishing with the use of explosives have already destroyed the foraging grounds of turtles such as coral reefs and sea-grass beds in the ocean
  3. The vast quantities of plastic and trash deposited on the beaches by visitors also threaten the survival of turtle.
  4. Eggs lay on beach are catched by human for eating
  5. The turtles are also poached for their meat, fat, shells and leather. 
  6. Dogs, cats, monkeys, monitor lizards and more dig up the nest and eat the eggs.
  7. Lossing and destroying the nests due to beach erosion and over-wash