The smallest sea turtle in the world, with the tiniest home range and the lowest overall population numbers, the Kemp’s ridley has the dubious distinction of being the world’s most critically endangered sea turtle.

The uniqueness of the Kemp’s ridley stems from the fact that its biology and ecology are fully adapted to the Gulf of Mexico. It is well known for inhabiting coastal and estuarine environments at the base of the numerous river systems that contribute water and nutrients to the Gulf of Mexico. Furthermore, it feeds on invertebrates such as blue crabs that flourish in those nutrient-rich estuarine environments. But the most distinctive aspect of the Kemp’s ridley is its reproductive biology. The entire species migrates to a single primary nesting beach near Rancho Nuevo, Mexico, where it exhibits a daytime mass nesting (arribada) behavior that can involve thousands of turtles coming ashore nearly simultaneously on one small stretch of beach. This unique phenomenon enhances the production and survival of hatchlings, which are carried by currents away from Rancho Nuevo and eventually into developmental habitats throughout the Gulf of Mexico and along the Atlantic coast of the United States.

The Kemp’s ridley also has a cultural history that spans the entire Gulf of Mexico. Although all major nesting occurs in the far western Gulf of Mexico, this species was initially described far to the east, in the Florida Keys, in 1880. The discovery started a scientific riddle (an abundant species with no known nesting beach?) that took more than 80 years to solve. By the time the Kemp ridley’s remote Mexican nesting beach was finally discovered by the scientific community in 1963, the population was already in steep decline, and by the mid-1980s the species was on the brink of extinction, with only a few hundred females nesting each year at Rancho Nuevo. Its spiral toward extinction launched one of the most comprehensive and successful conservation efforts on record.

The binational program included heroic efforts by a wide variety of agencies, organizations, and individuals; an expensive and risky binational experiment to establish nesting beaches in Texas, U.S.A.; and even a massive program to implement the use of turtle excluder devices on shrimp boats throughout the Gulf and southeast Atlantic coast of the United States. By the early 2000s, the effects of these valiant efforts were obvious; the Kemp’s ridley was on an exponential recovery trajectory that was expected to continue for decades. However, the recovery hit an unexpected slowdown in 2010. The reasons for this latest riddle in the ridley story are not clear, but the binational conservation efforts are continuing, and for now, the Gulf of Mexico continues to embrace its own unique species of sea turtle, the Kemp’s ridley.

This article originally appeared in SWOT Report, vol. 15 (2020). Click here to download the complete article as a PDF.