The Story of the Kemp's Ridley

A Kemp's ridley sea turtle nests on Padre Island
A female Kemp's ridley sea turtle nests on Padre Island.

NPS Photo


The Kemp's ridley is the most endangered of all sea turtle species. Efforts to save this turtle began in the 1960s and have continued to today. Since those efforts began, much has been learned about the Kemp's ridley. Many more questions remain unanswered.

But this is nothing new. In fact, the story of the Kemp's ridley begins with a riddle.

 

The Riddle Turtle

For a long time, the Kemp's ridley was a real mystery. Sailors, explorers, and fishermen had seen other kinds of sea turtles coming up to nest on beaches in various places around the world. They had seen those turtles lay eggs, and seen their nests hatch. Scientists had studied them. But it seemed no one had seen a Kemp's ridley nest. Some thought it might not even be a species. They suggested it was a hybrid, an infertile offspring of two other species. But when fishermen caught some Kemp's ridley sea turtles with eggs inside them, the riddle deepened. If these turtles were a separate species, where did they nest?

Scientists searched for the nesting grounds of this sea turtle with no success. In 1951, the first published record of a Kemp's ridley nesting anywhere in the world was submitted by J.E. Werler. The turtle was seen nesting in 1948 on what would later be designated as Padre Island National Seashore.

But there were thousands of Kemp's ridley turtles out in the Gulf of Mexico at that time. Where did the majority of them nest? Finally, in the early 1960s, Dr. Henry Hidebrand from Corpus Christi, Texas, came upon some home video footage that would solve the mystery and launch an international campaign to save a species.

 
1974 Kemp's ridley arribada by Andreas Herrera
1947 film footage taken by Andreas Herrera showed thousands of Kemp's ridley sea turtles nesting on one stretch of beach at Rancho Nuevo, Tamaulipas, Mexico.

Andreas Herrera

A Mystery Solved

Architect Andreas Herrera traveled between the U.S. and Mexico regularly in the 1940s. He had his own small plane and usually flew along the coast. He had heard rumors that hundreds of turtles sometimes crawled up onto one of the beaches he flew over. He was interested in seeing these turtles, and started taking a video camera with him on his trips in case he ever saw them.

One summer day in 1947, he looked down as he flew over an area in Mexico called Rancho Nuevo and saw a beach covered with turtles. Excited, he found a place to land his small plane, got his video camera, and captured the turtles on film.

That video footage wasn't discovered by the scientific community until the early 1960s, when Dr. Hildebrand saw it. Scientists were amazed - nothing like it had ever been seen. Thousands of sea turtles were on the beach, digging holes and laying eggs. There were so many turtles, some even dug up the eggs of others as they laid their own. The scientists estimated that 40,000 female Kemp's ridley sea turtles had come ashore to nest on that one day on the 16-mile stretch of beach at Rancho Nuevo (Hildebrand 1963).

Finally, the mystery was solved and the nesting grounds of the Kemp's ridley became known to the scientific world. But with the good news came the bad: this species was in serious trouble.

Watch a YouTube clip of Hererra's 1947 video (note this clip is not a National Park Service video or site)

 
Protected beach at Rancho Nuevo, Mexico
The beach at Rancho Nuevo in Tamaulipas, Mexico, in the 1970s.

NPS photo

A Turtle in Trouble

The 1947 film footage taken by Andreas Herrera showed the incredible mass nesting of tens of thousands of Kemp's ridley sea turtles on the beach at Rancho Nuevo in Tamaulipas, Mexico. Unfortunately, it also showed mass destruction. Scientists reviewing the footage in the 1960s saw people taking the turtles' eggs as they were laid and loading them by the millions into trucks. Some of the nesting females were also taken. The scientists estimated that 90% of the turtle nests were destroyed the same day they were laid.

If 90% of the nests laid were being destroyed, how long could the species survive? How long had this wholesale destruction been going on? Conservationists and scientists traveled to Rancho Nuevo and found the turtles were still nesting each year but had already declined dramatically since the film was taken years earlier. They appealed to the Mexican government to stop the wholesale destruction that was still taking place.

In 1966, the Mexican government took action. They passed legislation protecting the beach at Rancho Nuevo and brought in guards to stop the taking of eggs and turtles. Despite these protection efforts, the number of Kemp's ridley nests found each year continued to drop. By 1985, only 702 nests were found worldwide the entire year. Was it too late?

 
A Kemp's ridley on the beach on Padre Island
A Kemp's ridley sea turtle nesting on Padre Island.

NPS photo

A Bold International Experiment

Rancho Nuevo is the heart, but not the entirety, of the Kemp's ridley nesting range. By the time scientists discovered it, the species was already plummeting toward extinction. As conservationists and scientists scrambled to learn more about the Kemp's ridley and how to save it, they found records indicating this sea turtle had historically nested on other beaches, as far south as Veracruz in Mexico and as far north as Mustang Island in Texas.

In the 1970s, the U.S. joined efforts to save this species. At the time, almost all known nesting of Kemp's ridley sea turtles was occurring at Rancho Nuevo. Nearly all Kemp's ridley eggs were literally in one basket! What if a hurricane, oil spill, or other disaster wiped out that beach? The species was very vulnerable. The situation was dire.

In 1974, the National Park Service proposed re-establishing a nesting colony at Padre Island National Seashore (PINS). The seashore is part of the native nesting range of the Kemp's ridley and offers long-term protection for the turtle, its nests, and its nesting habitat. Boosting nesting at PINS would help to re-establish a nesting colony at the northern end of the Kemp's ridley historic nesting range at a protected area in the U.S. where nesting had previously occurred. It would also provide safeguards against species extinction.

In 1978, agency officials from Mexico and the U.S. and conservationists agreed to attempt to re-establish a secondary nesting colony at PINS to help save the species. They formed an international, multi-agency partnership and established the Kemp's Ridley Sea Turtle Restoration and Enhancement Program (KRREP). The National Park Service led development of an action plan for the KRREP. The goals of th eplan were to re-establish a Kemp's ridley nesting colony at PINS and to protect nesting turtles, eggs, and hatchlings at Rancho Nuevo (Caillouet et al. 2015, Shaver and Caillouet 2015).

This project was based on the theory that sea turtles imprint to their natal beach and that, as a result of this imprinting, adult females return to the beach where they hatched to lay their eggs. This theory was unproven at the time, and no project of this magnitude had been attempted before. But the Kemp's ridley was on the verge of extinction, and bold actions were needed to save the species.

 
Staff pack Kemp's ridley eggs in Padre Island sand during the Imprinting and Headstarting Project.
Staff pack Kemp's ridley sea turtle eggs with sand from Padre Island as part of the Imprinting and Headstarting Project conducted in the 1970s-1980s.

NPS photo

The project began right away. From 1978-1988, eggs from a portion of the Kemp's ridley nests laid each year at Rancho Nuevo were collected, packed in sand from Padre Island, and transported to PINS. Overall, a total of 22,507 eggs were collected and relocated through this project. Once the nests arrived at PINS, they were incubated under controlled conditions and hatched. The newly hatched turtles were released on the beach at PINS, allowed to crawl on the beach and into the surf, and then recaptured using aquarium dip nets after a brief swim in the Gulf of Mexico. This procedure was done in the hope that the hatchlings would imprint to the National Seashore and the females would return as adults to nest on Padre Island. This was the imprinting portion of the project.

 
The National Marine Fisheries Laboratory during the Imprinting and Headstarting Project.
The National Marine Fisheries Laboratory in Galveston housed the Kemp's ridley turtles during the Headstarting portion of the project.

NPS photo

Once the hatchlings were recaptured, they were transported to the National Marine Fisheries Service Laboratory in Galveston, Texas for the headstarting portion of the project. The turtles were kept and reared in Galveston for 9-11 months. The purpose of this headstarting was to allow the turtles to grow large enough to avoid most predators and to be tagged for future recognition to help evaluate project success.

 
A juvenile Kemp's ridley gets a living tag
A juvenile Kemp's ridley is tagged with a living tag during the Imprinting and Headstarting Project conducted from 1978-1988.

NPS photo

After 9-11 months, the turtles were about 8 inches long. Each turtle was tagged with a numbered metal tag on its front flipper. Starting in 1982, each turtle was also marked with a "living tag" - a small plug of the lighter bottom shell (plastron) implanted into the darker upper shell (carapace). Finally, at one year of age, the turtles were released into the wild. Most were released into Gulf of Mexico waters off Mustang and North Padre Islands.

 

The Waiting Begins

How long does it take for a Kemp's ridley sea turtle to reach the age where it comes back to nest? At the time of this ambitious Imprinting and Headstarting Project, no one knew. In 1986, eight years after the first turtles from the project were released, PINS staff began systematically searching the beaches from April to August for signs of nesting. But sporadic nesting of Kemp's ridleys had occurred on Padre Island since before the project began. So they could only verify that a nest was laid by a female from the project if they saw the nesting turtle. For years, a few nests were found but no females from the project were seen. Did this experiment work? Were they able to successfully imprint eggs from Mexico to Padre Island?

 
A Kemp's ridley with a living tag nests on Padre Island.
In 1996, a Kemp's ridley with a living tag was documented nesting on Padre Island.

NPS photo

Finally, in 1996, beach patrollers found a Kemp's ridley with a living tag nesting on Padre Island! It was the first of dozens of females from the Imprinting and Headstarting Project that have been documented nesting on North Padre Island.

 

The Uphill Climb

Conservation efforts to save and recover the Kemp's ridley have continued and expanded over the years since the Imprinting and Headstarting Project ended in 1988. In Texas, organized patrols to find and protect Kemp's ridley and other sea turtle nests are now conducted not only at PINS but also in many other areas along the Texas coast. Through these programs, conducted by the National Seashore and many partners, Texas beaches are monitored each summer and any nesting sea turtles or nests found are protected. In Mexico, nest detection and protection programs that began at Rancho Nuevo have also increased and expanded to include most of the species nesting range in Mexico.

 
Two park rangers install protective enclosures over sea turtle nests buried in the sand on Padre Island.
Park Rangers install protective covers over sea turtle nests that were found at Padre Island National Seashore and moved to a protective enclosure. The covers prevent parasitic flies from destroying the sea turtle eggs.

NPS photo

Protection of sea turtle nests is a key strategy in the fight to save the Kemp's ridley. Nests left where they are laid are at risk of predation, crushing by vehicles, tidal inundation, and other dangers. To increase hatching and suvival of hatchlings, sea turtle nests found at PINS and on most Texas beaches are moved to protected areas and monitored until they hatch. Most nests are also moved to protected areas or otherwise protected in Mexico. After hatching, the tiny hatchlings are released into the wild, usually within 24 hours. At Padre Island National Seashore, the public is invited to watch some of these hatchling releases as long as it is compatible with the needs of the turtles.

 

In addition to protecting nests and boosting reproduction, other conservation measures have been taken to help the Kemp's ridley recover to healthy numbers. Research is being conducted to find out what areas in the marine environment are important for their survival. Nesting habitat is being protected. And actions are being taken to reduce stranding of Kemp's ridley and other sea turtles.

 
A dead stranded sea turtle in a shrimp fishing net and a live sea turtle escaping from a shrimp fishing net
On the left, a dead stranded Kemp's ridley sea turtle caught in a shrimp fishing net found on Padre Island. On the right, a young loggerhead sea turtle escapes from a shrimp fishing net through a Turtle Excluder Device.

Left: NPS photo. Right: NOAA photo.

Stranding occurs when a turtle is no longer able to swim and floats helplessly in the water or washes up onto shore, alive or dead. It can be caused by injury, disease, severe cold weather, entanglement in floating trash, incidental capture in fishing nets, and other hazards.

To help reduce stranding caused by incidental capture in nets used to catch shrimp in the Gulf of Mexico, devices were developed that allow most sea turtles to escape from those nets. These Turtle Excluder Devices (TEDs) are now required on all shrimping boats along the Texas coast and in many other areas. Beginning in 2000, Texas Parks and Wildlife Department closed nearshore waters off south Texas to shrimp trawling from December 1 through May 15, which provided a nursery area for shrimp and a protective zone for migrating and nesting adult Kemp's ridley turtles. In Mexico, Gulf waters off Rancho Nuevo are also protected, with no shrimping or other commercial fishing allowed. Since these combined measures have been implemented, the number of Kemp's ridley sea turtles found stranded has decreased significantly.

 
2011 mass nesting of hundreds of Kemp's ridley sea turtles in Mexico
In 2011, several thousand Kemp's ridley sea turtles came ashore to nest in one day at Rancho Nuevo in Tamaulipas, Mexico. Such mass nesting events, called arribadas, happen several times each summer.

Photo from National Marine Fisheries Service, taken by Toni Torres of the Gladys Porter Zoo

The Results Are In - Or Are They?

Many years of combined conservation measures taken by PINS and many local, state, national, and international partners resulted in a substantial increase in the number of Kemp's ridley nests found in Texas and in Mexico from 1997 through 2009. In 1996, only 6 Kemp's ridley nests were found in Texas; in 2012, 209 nests were found in Texas (Shaver and Caillouet 2015). After reaching a low of only 702 nests worldwide in 1985, Kemp's ridley nesting increased to a peak of nearly 20,000 nests worldwide in 2009! Conservation was working, and the species was on its way to recovery.

 

Unfortunately, this upward swing has taken a sudden and unexpected reversal in recent years. After 13 years of consistent increase, Kemp's ridley nesting decreased in 2010 and has fluctuated at reduced levels since then. Scientists are still working to determine the cause of this reversal.

 
Kemp's ridley hatchlings crawl across the beach.
Tiny Kemp's ridley sea turtle hatchlings crawl toward the Gulf of Mexico on Padre Island.

NPS photo

The sudden and unexpected decline in Kemp's ridley numbers demonstrates the importance of contiued monitoring, protection, and conservation measures. History has shown that even when this species seemed lost, intensive efforts and cooperation between agencies, organizations, states, and nations turned the tide in favor of the Kemp's ridley. Conservation works, but requires combined efforts from many different partners and from many different directions. With the help of many partners, volunteers, and people like you, we can identify and address this most recent challenge to the recovery of the Kemp's ridley. Together, we can ensure our children and grandchildren can watch newly hatched Kemp's ridley turtles make their way across the beaches of Texas and Mexico.

 

Literature Cited:

Hildebrand, H.H. 1963. Hallazgo del area de anidacion de la tortuga marina "lora", Lepidochelys kempii (Garman), en la costa occidental del Golfo de Mexico (Rept., Chel.). Sobretiro de Ciencia, Mexico 22:105-112.

Shaver, D.J., and C.W. Caillouet, Jr. 2015. Reintroduction of Kemp's ridley (Lepidochelys kempii) sea turtle to Padre Island National Seashore, Texas and its connection to headstarting. Herpetological Conservation and Biology 10 (Symposium):378-435.

Werler, J.E. 1951. Miscellaneous notes on the eggs and young of Texas and Mexican reptiles. Zoologica 36:37-48.

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Last updated: May 2, 2018

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