Description
The Atlantic Ridley Turtle is the smallest sea turtle
found in Canadian waters, reaching a maximum of 75 cm carapace length. The
greyish-green carapace is broader than long,
especially in
adults. It can be distinguished by the 3-5 raised knobs along the
back and serrations along the back edge of the carapace. The plastron is pure white. The
paddle-like
limbs are grey and the males have a long curved claw on each
forelimb and a long prehensile tail.
Confusing Species
The Atlantic Ridley Turtle is similar to the other
hard-shelled sea turtles but is smaller than either the Loggerhead Turtle or the Green Turtle. Neither of these
turtles have
the raised knobs along the back although the Loggerhead has a keel. The shape of the carapace also differs.
Distribution
The Atlantic Ridley is an Atlantic sea turtle.
Although adults rarely venture out of the Gulf of Mexico, juveniles
are occasionally seen along the coast of Nova Scotia and
Newfoundland in the summer.
Habitat
This sea turtle prefers relatively shallow water (less
than 50 m deep) compared with other species. Juveniles hide and
feed in large mats of algae or sea-grass. The preferred nesting
area is a beach of white sand on the seaward side of an elevated
dune where the tides are relatively small.
Reproduction
Individuals probably take 10-12 years to reach sexual
maturity. Most nesting occurs along an 18 km stretch of beach in
the Gulf of Mexico. Females nest every 1-3 years. Several
clutches of up to 185 eggs are laid from April to July. Most
females will emerge from the water to nest on the same night. Sex
determination is temperature-dependent. Unlike other species of
sea turtles, hatchlings may emerge during any kind of weather and
not all hatchlings from a nest emerge at the same time. The young
turtles are 4-5 cm in length.
Natural history
Very little is known about this elusive sea turtle.
Atlantic Ridley's feed primarily on crustaceans such as crabs and
molluscs. Juveniles are occasionally stranded on beaches
apparently after being stunned by an influx of cold water. One
tagged female moved over 5000 km from the Gulf of Mexico to the
coast of Colombia.
Conservation Concerns
The Atlantic Ridley has declined dramatically during
the last 50 years and is considered the most endangered species of
sea turtle. The initial cause of their decline was egg collecting
which has been substantially reduced, but adults are also drowned
in fishing gear. The most serious threat is disruption of their
nesting beaches.
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