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Defining the geographical range for a population of sea turtles in the ocean is difficult. Sea turtles are highly migratory animals, and the life histories of all the species exhibit complex movements and migrations through geographically disparate habitats. By virtue of the highly migratory behavior of the adult turtles, and the shifting habitat requirements of post-hatchlings and the populations of sea turtles are difficult to track because of the national boundaries, such as the Nation of Cuba and other such international boundaries.
Sea turtles belong to family Cheloniidae. Six of the seven known species of sea turtle reside in this family, and range throughout the world's oceans, extending virtually to the tips of the southern continents and northwards almost to Scandinavia. The largest species is the loggerhead (Caretta caretta), and although those caught today seem relatively small, much bigger individuals have been recorded in the past. A skull originating from a loggerhead captured in Australian waters measures nearly thirty cm or one foot in diameter, and the turtle it self probably weighed as much as five hundred-forty kilograms or one thousand ninety-two pounds.
In contrast, the Atlantic or Kemp's ridley (Lepidochelys kempi) rarely exceeds eighty-one kilograms or one hundred eighty pounds. As its name suggests, this species is confined to the Atlantic notably around the Gulf of Mexico. And is not often seen but is not extremely rare either. It is sometimes seen off European coasts. It may have become isolate after the closure of the Panamanian land bridge about four million years ago.
The Olive ridley (Lepidochelys olivavea) is larger in size, and has a much wider distribution, extending into the Pacific Ocean. Relatively little is known about the habits of this tropical species, in contrast to those of the equally wide-ranging green turtle (Chlonia mydas), which have been very extensively studies in various parts of its range. A number of interesting areas in the northern central part of the Gulf of California, including the fact that the turtles actually become dormant when the temperature of the sea falls. They burrow into the seabed and remain there from about November to March.
The size of the green turtle can vary quite considerably trough its range. Those found on the beaches of Ascension Island and Surinam are the largest, with the record being held by a green turtle from the former locality, which measured One hundred thirty-eight centimeters or fifty-five inches across its carapace. This may be related in part to the lack of predation on the species when it nests on Ascension Island. Certainly, even bigger individuals occurred in the past probably weighing as much as four hundred fifty-three kilograms or a thousand pounds. These were often found around the cast of Cedar Key. Florida, where today the species has become scarce, and only small individuals are recorded.
Where turtles are hunted, there is little opportunity for individuals to grow to a large size. In spite of being highly prolific, and laying over One thousand eggs in the course of a breeding season, green turtles are vulnerable to the effects of predators. Studies have shown that, in some cases about one quarter of the population can be killed annually, while the turtles themselves only lay every three years on average. It is easy to see how severe population decline can follow a sustained period of harvesting. Threats to sea turtles are broadly defined as any factor that jeopardizes the survival of the sea turtles or impedes the recovery of their populations. Twenty-six kinds of threats have been identified. Some of the more major problems are urbanized islands such as Hawaii, Guam, And the CNMI, or the Common Wealth of the Northern Mariana Islands. Another problem is Islands that are under construction and becoming urbanized islands such as American Samoa except Rose Atoll, Republic of Palau, the uninhabited islands of CNMI, and also the Federated States of Micronesia, and the Republic of the Marshall Islands, the RMI and the FSM.
In sea turtles Mating precedes egg-laying by twenty five days. Adult female green turtles emerge at night to excavate nests and deposit eggs during the warmer months of the year at sites usually far removed from their resident foraging pastures. The problem with urban development on Islands where turtles lay their eggs is that if a turtle
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Sea turtles, Cryptodira, Pantestudines, Cheloniidae, Sea turtle, Green sea turtle, Threats to sea turtles, Turtle, Loggerhead sea turtle, Kemps ridley sea turtle, Ridley sea turtle, Olive ridley sea turtle
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