Some Galápagos 'yellow' sea turtles remain homebodies, surprising scientists
Sea turtles are famous for being prodigious wanderers. Guided by Earth's magnetic field, ocean currents and the sun, they tend to crisscross the seas in search of food, returning to the region of their birth every few years to breed. So when scientists discovered a population of sea turtles that appear to be very much homebodies, they were taken aback.
Recent research reveals that yellow-morph green sea turtles found in the Galápagos are more inclined to stay close to their birthplace than previously thought. These sea turtles, one of two genetically distinct forms of green sea turtles, typically roam vast distances in the Pacific Ocean to breed. However, a study published in Frontiers in Amphibian and Reptile Science found that these Galápagos yellow-morph green sea turtles remain within the Galápagos Marine Reserve for up to three years.
This discovery comes as a surprise to scientists, who had expected the turtles to migrate to distant beaches in the western Pacific for reproduction. The study, led by Dr. John W. Rowe from Alma College, involved tagging seven adult male and two adult female yellow-morph green sea turtles with electronic devices that transmitted signals to satellites.
The turtles were tracked for up to 418 days, spending most of their time in shallow coastal waters near individual islands. While some turtles stayed around a single island during the study, others traveled between Isabela and San Cristóbal, Isabela and Española, or Isabela and Santa Cruz. The average home range of a single turtle was approximately 1,498 square kilometers, although this varied among individuals.
Despite these findings, the researchers caution that the study only provides a snapshot of the turtles' behavior and that periodic long-distance migrations may not have been captured. Dr. Juan Pablo Muñoz Pérez, co-author from the Universidad San Francisco de Quito, suggests that female yellow-morph green sea turtles typically do not nest on the Galápagos beaches and will eventually migrate to their natal beaches in the western Pacific to breed.
In contrast, female black-morph green sea turtles, which do nest in the Galápagos, may either remain year-round residents, travel to other nearby islands, or visit feeding grounds off the coasts of Central and South America. The study emphasizes the importance of preserving the pristine coastal and between-island routes that these turtles use for foraging, as individual turtles may rely on waters around multiple islands.
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