Sea Turtle Biology
There are seven species of sea turtles worldwide. They are: (left to right) leatherback, Kemp’s ridley, green, hawksbill, loggerhead, and olive ridley sea turtles.
All sea turtles found are listed as either threatened or endangered under the Endangered Species Act.
Human threats, including oil spills, have significantly reduced many sea turtle populations in recent centuries.
Sea turtle populations takes a long time to recover because they grow slowly and do not reproduce every year.
Sea Turtle Life History
Sea turtles rely on a variety of habitats that can be damaged by man’s activities.
Nesting Females, Eggs, and Hatchlings
With the exception of basking green turtles in Hawaii, the only time turtles crawl ashore is for the females to lay their eggs. Females lay their clutches of eggs every 2-4 years on beaches, then return to the ocean. The embryos develop buried in the sand for around 45-60 days. Hatchlings emerge from their nests, quickly crawl to the surf, and begin a marathon swim to find refuge within offshore areas.
Juveniles, Surface-Pelagic Life Stage
Most post-hatchling turtles live at the surface of the open ocean. Turtles at this stage have limited diving ability, and spend more than 80% of their time at or near the surface.
Large Juveniles and Adults
Large juvenile and adult sea turtles spend most of their time in shallower water, along the continental shelf or nearshore environments. At this age they have developed into active swimmers, diving frequently to depths greater than 65 feet.
Sea turtles have extremely accurate navigational systems that allow them to migrate between widely separated feeding and breeding grounds.