How Might Proposed Cuts Impact Kemp’s Ridleys in Texas & Beyond?
A recent news article about proposed changes to conservation measures of the world’s most endangered sea turtle, the Kemp’s ridley, at Padre Island National Seashore in Texas, USA caught our attention. We asked Kemp’s ridley expert Dr. Patrick Burchfield a few questions about that story, and about the overall status of the Kemp’s ridley conservation efforts in both Texas and Mexico. Read on for the full Q&A.
A recent Kemp’s ridley arribada in Mexico. Populations have recovered to the point that arribadas are happening once again, but an unexpected drop in nesting since 2010 is causing concern among conservationists. © HÉCTOR CHENGE
SWOT: How important is the Kemp’s ridley nesting population in Texas and Padre Island in particular?
Pat: Simply put, I feel that the Padre Island Kemp’s cohort is critically important to ensure this taxon’s future survival if some catastrophe should befall the Mexican nesting beach.
In 1977-78 geneticists were suggesting that the Kemp’s might be headed towards extinction due to declining numbers and a lack of genetic diversity, and several strategies were discussed to reverse that trend, including the establishment of an “assurance colony” (read more about this in the SWOT Report articles highlighted below). It was simply too risky to have almost the entire global nesting population on one small stretch of isolated Mexican beach, where it could be at risk from both anthropogenic threats such as oil spills, beachfront development, climate change, direct take, or lack of budget for protection efforts, as well as natural threats like hurricanes, erosion, and more. Unlike other sea turtle species, which nest in multiple localities and have multiple sub-populations, the Kemp’s literally puts all of its eggs in one basket! Another basket needed to be found.
The Texas coast made sense, as the first Kemp’s nest in the U.S. was reported in the Padre Island area in 1948 (Werler 1951). Moreover, R.W. Doughty (1954) recounted a story from the spring of 1851 in which the wife of a Lt. Egbet Viele described a horse drawn trap ride down the beach near Galveston as sunset approached where she and her husband encountered “swarms” of waterfowl and “clusters” of mammoth green turtles basking in the hot sand. Doughty stated that these were probably green turtles or perhaps loggerheads or some other species. The time of year and the fact it was daylight suggests strongly that they were Kemp’s. This and other evidence suggest that, in the past, Kemp’s probably nested all along the Texas coast wherever primary sand dunes exist near to the water. In the 1980s I did several overflights of the Gulf of Mexico beaches from Galveston to Veracruz with a friend, Buddy Mattix, and we saw sporadic tracks on virtually every potential nesting beach from South Padre Island south, wherever the beach profile fit the Rancho Nuevo model (dunes near the water). A fair number of the tracks were at Playa Bagdad just south of the Rio Grande and east of Matamoros, but that is a difficult area to monitor for various reasons.
Padre Island National Seashore (PAIS) had already been scientifically verified as a historic nesting beach for Kemp’s, backed by anecdotal information acquired by the late Drs. Archie Carr and Henry Hildebrand, and most importantly it could afford legal protection for the species and its habitat, so the site made perfect sense as a location for this assurance colony
SWOT: National Park Service officials are proposing to move away from gathering and incubating Kemp’s ridley eggs at PAIS. Do you think it is necessary to gather and artificially incubate eggs at Padre Island?
If the goal is to establish a viable assurance nesting population of the Kemp’s, protective corrals and/or artificial incubation are needed. Individual nests left in situ without elaborate protection, which is logistically very difficult and expensive, would probably not survive at PAIS based on our historical and present-day experience in Mexico. In addition to natural predators and climate threats, Padre Island National Seashore also has public tourism along with vehicular traffic, which we do not have to deal with in Mexico. In the early days at Rancho Nuevo a biology student, Ignacio Flores Silva, did a study on predation that indicated that nests left in situ experienced an average of seven predator attacks per nest per night. Based on his work and the difficulty of protecting widespread nests from persistent coyotes, intelligent raccoons, skunks, and other predators, protective corrals that could be regularly checked near base camp were the only viable option. Conditions at PAIS are different, of course, but hatcheries still seem to be the safest approach. And, with the exception of one season when sand moisture was excessive, the hatchery at PAIS has matched or exceeded the percentage of hatching success in facsimile nests in beach corrals in Mexico. The PAIS program has since monitored and learned to manage their hatchery temperatures and hatchling sex ratios, and has honed this to an exact science that would even allow us to create more males in the laboratory if that becomes a problem in the future due to global warming and female-skewed populations.
SWOT: National Park Service officials have also stated that public hatchling releases are “discretionary” and “should be reduced,” what is the potential impact (positive or negative) of reducing public hatchling releases?
The more involved the general public becomes in conserving a particular species, the more likely politicians, policymakers, and bureaucrats are to support funding and to enforce the conservation laws and regulations intended to protect that species. Public hatchling releases are extremely popular and have resulted time and time again in creating lifelong advocacy and support for conservation. The public needs to identify with keystone or flagship species if one wants to protect their respective ecosystems. There is nothing that can replace a personal encounter with a tiny baby turtle scurrying towards the enormity of the waiting surf and realizing the luck it will take to survive to become an adult. As long as the releases allow for the natural imprinting process and sea finding orientation and frenzy, I think they are very beneficial to species conservation. Most Kemp’s ridley hatchlings emerge under the cover of darkness between 02:00 and 07:00 AM (dawn) and, as such, hatchling releases should conform to the turtles’ biological needs and not to those of the public observers. The use of red lights can help visitors see in the dark and not affect the hatchlings’ sea finding orientation. The public can be a powerful source of much needed support. Reducing public releases is definitely a negative.
SWOT: Is the Kemp’s ridley conservation program succeeding in its main nesting beaches in Mexico?
Pat: The epicenter on Earth for Kemp’s ridley reproduction is the ~90 mile stretch of beach in the Mexican state of Tamaulipas to the north and south of the town of Rancho Nuevo. More than 99% of all nesting females haul ashore to nest on these and a few secondary beaches in Veracruz state. In response to a severe decline in Kemp’s numbers, the Mexican government began to survey these populations in 1966, and to protect nests and hatchlings in earnest in 1967. In 1978, Mexican and U.S. biologists started the binational Kemp’s ridley population restoration project spearheaded by Dr. René Marquéz Millán and Dr. Peter C.H. Prichard. This effort ultimately reversed what seemed to be the otherwise certain extinction of the species. The decline leveled off in the late 1980s and began a slow but steady increase. We’ve experienced ups and downs, but are still nowhere near the population size in 1947, when Andrés Herrera filmed an estimated 26,906-40,000 females nesting in a single day (June 18, 1947) at Barra de Calabazas, Rancho Nuevo, Tamaulipas. 2017 set a recent high with 23,732 nests for the season representing ~8,000 females, but then in 2019 we dropped back to 11,090 nests (~4,436 females) leaving us to wonder: where are the ridleys? This year – 2020 – the question was answered, and at the time of this writing (early August) more than 20,000 nests have been recorded. And the season isn’t over yet, so we could see another historic high! Mexico’s CONANP, PROFEPA, the State of Tamaulipas, and Rancho San José 60 (an NGO), along with the binational team, have done an outstanding job in the face of limited funding and COVID-19.
Dr. Patrick Burchfield is the Director of the Gladys Porter Zoo in Brownsville, TX USA, and serves as the U.S. coordinator of the bi-national multi-agency Kemp’s Ridley Sea Turtle Restoration & Enhancement Project in Mexico. He has been dedicated to protecting the Kemp’s ridley since 1973.
For more information, see these SWOT Report articles featuring the Kemp’s ridley:
1. Eckert, K., et al. 2020. Sea Turtles of the Caribbean. In SWOT Report—The State of the World’s Sea Turtles, vol. 15: 14-27.
2. Perrault, J.R., Foley, A.M., Flewelling, L.J., and Manire, C.A. 2019. Florida’s Red Tides and Their Impacts on Sea Turtles. In SWOT Report—The State of the World’s Sea Turtles, vol. 14: 10-11.
3. Wibbels, T., and Bevan, E. 2018. The Conservation Status of Kemp's Ridley Worldwide. In SWOT Report—The State of the World’s Sea Turtles, vol. 13: 32-33.
4. Horvath, E. 2016. The Deadly Bucket. In SWOT Report—The State of the World’s Sea Turtles, vol. 11: 42-43.
5. Wibbels, T., and Bevan, E. 2015. New Riddle in the Kemp's Ridley Saga. In SWOT Report—The State of the World’s Sea Turtles, vol. 10: 14-17.
6. Witherington, B., and Jones, T.T. 2011. When Disaster Strikes. In SWOT Report—The State of the World’s Sea Turtles, vol. 6: 16-21.
7. Mast, R.B. 2010. Editor’s Note: The Ridleys – Reasons for Hope. In SWOT Report—The State of the World’s Sea Turtles, vol. 5: 13.
8. Safina, C., and Wallace, B. 2010. Solving the “Ridley Riddle”. In SWOT Report—The State of the World’s Sea Turtles, vol. 5: 26-29.
9. Witherington, B., Pendoley, K., Hearn, G., Honarvar, S. 2009. Ancient Mariners, Ancient Fuels: How Sea Turtles Cope with Our Modern Fossil Fuel Dependency. In SWOT Report—The State of the World’s Sea Turtles, vol. 4: 38-41.
10. Coyne, M.S. 2006. Plotting Kemp's Ridley's, Plotting the Future of Sea Turtle Conservation. In SWOT Report—The State of the World’s Sea Turtles, vol. 1: 20.
11. Mast, R.B., and Pritchard, P.C.H. 2006. Experts Define the Burning Issues in Sea Turtle Conservation. In SWOT Report—The State of the World’s Sea Turtles, vol. 1: 12-13.
12. Shaver, D.J., and Mast, R.B. 2006. Hope on the Horizon - Three Success Stories in the Making: The Return of the Kemp's Ridley to Texas Shores. In SWOT Report—The State of the World’s Sea Turtles, vol. 1: 6-7.