Sea Turtle Facts
|Sea Turtle Species
Loggehead Sea Turtle
Types of Turtles
Seven different sea turtles live and breed in tropical and subtropical oceans of the world.
All seven species have experienced significant population declines over the last couple of decades, and all are considered either vulnerable or endangered.
Habitat destruction or human encroachment in their traditional nesting grounds, along with increased fishing in their foraging areas, where they are accidentally captured as byproducts, and pollution are a few of the multiple factors that scientists cite as the primary factors contributing to their decline.
Turtle protection efforts continue in response to these problems. Pink tape around nesting site along the East Coast of the United States, for example, warn visitors stay clear of the area.
Sea turtles share many physical features. With the exception of the Leatherback, are grow hard shells.
With the exception of the Flatback and Kemp's Ridley turtles, the range of the species extends across the world's oceans.
Their extended range makes gathering behavioral data problematic. However, sea turtle research, including the production of reliable population statistics, continues to improve.
As scientists implement a standard population estimating procedure across regions and species, some of the problems associated with current population estimates will be resolved.
Green Turtles, the world's largest, hard shelled species, grow to three feet in length and weigh in at the 350 pound mark.
Green fatty tissue, a product of their herbivore diet, explains their name. Green turtles swim and nest in tropical areas around the equator.
The World Conservation Union (IUCN) estimates population declines between 48% and 67% over the past couple of decades, although they note problems inherent in calculating global populations.
Lack of definitive global population estimates, however, does not undermine the reliability of data from many of the regional population counts, and their explanations of counting techniques for the thirty two nesting sites included in their survey are transparent and replicable.
Two areas lead the list of largest Green Turtle nesting areas, Costa Rica and the Raine Island area population in the western Pacific Ocean.
Flatbacks (Natator depressus), medium sized marine turtles named for their flat shells, nest exclusively along Australian coastal areas. Their foraging range extends north to the oceans around Papua New Guinea and Indonesia.
The Australian Government lists them as vulnerable, with the eastern population the most stable, the western population the least stable and the northern population large, but in decline.
Flatback population dynamics are influenced by a variety of factors. Like other marine turtles, predatory behavior by local wild dogs, foxes and pigs depresses hatchling populations.
Commercial fishing practices, including the existence of abandoned nets which trap flatbacks in their foraging areas also creates population stresses.
Hawksbill Turtles (Eretmochelys imbricata), inhabit shallow water reefs throughout the tropics.
The name Hawksbill comes from the turtle's pointed beak, which is helpful for prying out sponges, their food of choice, from crevices in the coral reefs.
Their status as one of the most endangered marine turtle species is primarily attributed to human demand for their decorative shells.
Member states of the Convention on International Trade in Endangered Species (CITES) banned trade in tortoiseshells. Recently they turned down a request by the Cuban government to resume limited trade.
The effects of climate change on coral reef ecosystems, the Hawksbill traditional foraging ground, poses another potential long term threat to population stability.
The Kemp's Ridley Sea Turtle (Lepidochelys kempii), only breeds along the Northern Mexico and Southern Texas shores.
Like many Gulf Coast residents, its diet consists primarily of crabs, supplemented by shrimp, jellyfish and other local sea creatures. Its foraging range extends along the Atlantic Coast of the United States.
Ridley breeding habits make them vulnerable to drastic population drops. Both the Olive Ridley and Kemp's Ridley species exhibit centralized mating and nesting practices called arribadas.
Because females typically move, en masse, to a central nesting ground, any environmental threat to the breeding or nesting ground poses a threat to the entire population.
The Olive Ridley sea turtle (Lepidochelys olivacea): ranks among the most populous sea turtle species world wide.
Recent global population declines largely reflect a crash of the eastern Pacific population. Three Mexican states, Guerro, Jalisco and Oaxaca, that border the Pacific Ocean in Southwestern Mexico, once hosted large, and now depleted rookeries.
Leatherback Sea Turtles (Dermochelys coriacea), the world's largest marine turtles, easily reaching lengths over six feet long.
The name leatherback aptly describes its most important physical characteristic. It is the only soft shell sea turtle, and it is also considered warm blooded, with the ability to regulate its body temperature during forays into colder ocean water.
The IUCN listed Leatherbacks as critically endangered in 2000, noting significant population collapses in some of their most important Pacific nesting areas.
The most recent population research shows little population gain during the past decade. The Western Pacific region of Indonesia and Papua New Guinea may host the largest population of breeding females, with estimates at one thousand annually.
© 2007-2012 Patricia A. Michaels