Sea Turtles
Sea turtles are found in almost every ocean on the planet and are among the oldest sea creatures alive. They are closely related to land turtles, with 250 million of years of evolution. The first sea turtles, however, didn't appear until 200 million years ago.
Often granted mythological status by seafaring cultures, sea turtles have long been integrated into cultural and even religious rites.
Unfortunately, due to their meat and eggs, sea turtles have also served as an important food source. In recent years, their long migration routes through the open ocean have clashed with fishing fleets, causing a steep decline in their numbers. Worldwide, this has taken a dramatic toll on these graceful creatures. Many areas have enacted legislation and set up protection programs to ensure beaches are clear for sea turtles to lay their eggs.
Encounters
An encounter with a sea turtle can be a highlight of any dive, as they are often seen feeding, and swimming gracefully to the surface to breathe. Often curious about divers, sea turtles will often follow divers for long periods of time as they look for food.
Sea Turtles can also be seen laying eggs during certain season and in specific places, where they can 
come ashore in the hundreds to dig holes for up to 200 eggs.
The major families of sea turtles include: Loggerhead turtles; Green turtles; Black turtles; Leatherback turtles; and Olive Ridley turtles.
Class: Reptila
Order: Testudines
Diet: Jaw structure indicates whether sea turtles are omnivorous, carnivorous, or herbivorous. Diet ranges from sponges, tunicates and squid (Hawksbill) to jellyfish, tunicates and soft bodied creatures (Leatherbacks) to sea grasses and algae (Green and Black)
Basic Facts:
Since 1989, fishing trawlers in US waters must use Turtle Excluding Devices (TED's) to allow turtles to escape from fishing nets;
have a gland near their eyes to remove salt from their systems;
only females ever come ashore, with males and juveniles swimming in the open sea;
females always return to the same beach as they were born to lay eggs;
sea turtles hatch en masse to deter predators;
average swim speeds are between 1.5 and 2.3 kilometers per hour (.9 and 1.4 miles per hour);
can dive as deep as 1,000 meters (3,000 feet) in search of prey;
can't retract necks like land turtles, because it impedes swimming speeds.
Sea Turtle Conservation and Research Agencies:
Caribbean Conservation Corporation www.cccturtle.org
SeaTurtle.ORG www.seaturtle.org
Leatherback Trust www.leatherback.org
EarthWatch http://www.earthwatch.org/site/pp.asp?c=dsJSK6PFJnH&b=393551