Sea turtles are ancient marine reptiles that have navigated the world’s oceans for over 100 million years. They are found across various global waters, inhabiting a range of environments from vast open oceans to shallow coastal areas.
Diverse Marine Habitats
Sea turtles utilize a variety of marine environments throughout their lives. Many species inhabit warm, tropical, and subtropical waters, though some venture into temperate zones.
Coastal areas are important, including shallow waters, bays, lagoons, and estuaries. These nearshore habitats often feature seagrass beds, which serve as foraging grounds for herbivorous species like the green sea turtle. Coral reefs also represent a habitat, especially for species such as the hawksbill sea turtle, which forage on sponges. Mangrove swamps and other brackish areas, where freshwater mixes with saltwater, offer additional diverse environments for some turtles.
Beyond coastal zones, sea turtles also inhabit the open ocean, known as the pelagic zone, particularly during early life stages or for highly migratory species like the leatherback.
Global Species Distribution
Seven sea turtle species exhibit distinct global ranges. Loggerhead sea turtles have a widespread distribution, found in the Atlantic, Indian, and Pacific Oceans, and the Mediterranean Sea, with significant nesting concentrations along the southeastern North American coast and in Oman. Green sea turtles inhabit tropical and subtropical waters globally, with major populations in the Atlantic, Pacific, and Indian Oceans, nesting in over 80 countries. They are often found in coastal areas, particularly around islands with abundant marine plants.
Leatherback sea turtles possess the widest distribution of any reptile, ranging from cold waters off Alaska and Norway to the southern tips of Africa and New Zealand, primarily nesting on tropical and subtropical beaches. Hawksbill sea turtles are predominantly found in tropical and subtropical waters of the Atlantic, Pacific, and Indian Oceans, with a strong association with coral reefs.
The Kemp’s Ridley sea turtle has the most restricted range, mainly occupying the Gulf of Mexico, with nesting primarily occurring in Tamaulipas, Mexico, and occasionally in Texas. Olive Ridley sea turtles are globally distributed in warm and tropical waters of the Pacific, Indian, and South Atlantic Oceans. They are known for their mass nesting events, called arribadas, on a few specific beaches in the eastern Pacific and Indian Oceans. The Flatback sea turtle has the smallest geographic range, living exclusively on the continental shelf waters of northern Australia, southern Indonesia, and Papua New Guinea, where they also nest.
Life Stage Habitat Shifts
A sea turtle’s habitat changes significantly throughout its life, reflecting different needs at various developmental stages. After emerging from their nests on sandy beaches, hatchlings embark on an initial journey to the open ocean, often seeking refuge and food in floating mats of seaweed, such as sargassum, for their first few years. This pelagic phase, sometimes referred to as the “lost years,” takes place far from coastal areas.
As sea turtles grow into juveniles, their habitat preferences can vary depending on the species. Some juveniles may remain in oceanic waters, while others transition to coastal developmental habitats like bays, estuaries, or nearshore waters. For example, juvenile loggerheads may utilize nearshore waters as developmental habitats before moving to deeper foraging areas.
Adult sea turtles typically inhabit shallow coastal waters, including bays, lagoons, and estuaries, returning to these areas for foraging. Females then undertake long migrations to specific sandy beaches to lay their eggs, often returning to the same general area where they were born.