Scientists in Brazil Mark and Release 15,000 Baby Turtles in Mass Hatching - via Herp Digest

Effort led by WCS and Chico Mendes Institute for Biodiversity Conservation

Mass hatching event for the Giant South American river turtle produces more than 200,000 hatchlings

NEW YORK (February 10, 2014)—Turtle biologists seeking to learn more about threatened and endangered turtles in Brazil’s Abufari Biological Reserve recently hit the mother lode—a mass hatching event producing an estimated 210,000 baby turtles, according to the Wildlife Conservation Society and the Chico Mendes Institute for Biodiversity Conservation.

An equally impressive statistic from the event: turtle researchers managed to mark and release approximately 15,000 Giant South American river turtle hatchlings in the event. Known in the conservation science world as “mark and recapture,” the methodology allows researchers to estimate the size of an animal's population, particularly when counting every or most individuals of a species is difficult. In this instance, WCS researchers marked the collected river turtle hatchlings so they could be easily identified in future surveys. Data from “recaptured” turtles help conservationists calculate dispersal patterns and survival rates.

“The marked turtles will hopefully provide important data that will help inform conservation plans to safeguard this species from exploitation,” said Dr. Camila Ferrara, Aquatic Turtle Specialist for the WCS Brazil Program.

Every year during the dry season, hatchlings of the Giant South American river turtle emerge en masse from river sandbanks of the Purus River basin in western Brazil. The mass hatching—one of the largest known for the species (Podocnemis expansa)—is an evolutionary strategy to ensure the survival of turtle hatchlings by overwhelming predators with sheer numbers, similar to the “arribadas” of the Olive ridley and Kemp’s ridley sea turtles. Nevertheless, only a small percentage of the hatchlings live to reach adulthood.

In order to maximize the number of hatchlings marked during the field expedition, the researchers constructed a fence around all identified turtle nests. The team then collected the emerging hatchlings.

The Giant South American river turtle is the largest of the side-necked turtle family and grows up to 80 centimeters (nearly three feet) in length. The species is only found in the Amazon River basin and is now threatened by unregulated consumption of the turtles’ meat and eggs.

“Turtles are among the most endangered species of vertebrates in the region and worldwide,” said Dr. Julie Kunen, Executive Director of WCS’s Latin America and the Caribbean Program. “Monitoring programs for these and other turtles and tortoises will provide a foundation for sound management plans in the years to come.”

The recent survey for both Giant South American river turtles and yellow-spotted Amazon river turtles was part of a new long-term WCS conservation program called Amazon Waters, an initiative focusing on the conservation of aquatic ecosystems and species, particularly freshwater turtles in the Purus, Negro, and Solimões River basins. Data gathered by the researchers will help answer questions on turtle biology (i.e. population structure, habitat usage) as well as provide information for environmental enforcement and education for local communities.

Captions for photos in sequenc

All images by: C. Ferrara/Wildlife Conservation Society-Attribution necessary.

1. Every year during the dry season in Brazil’s Abufari Biological Reserve, a mass hatching of Giant South American river turtles occurs, an event that produces hundreds of thousands of turtle hatchlings.

2. Researchers from the Wildlife Conservation Society and the Chico Mendes Institute for Biodiversity Conservation recently witnessed the emergence of an estimated 210,000 turtle hatchlings.

3. A Giant South American river turtle hatchling emerges from its shell.

4. The researchers used a fence to contain the turtle hatchlings emerging from identified nests. The scientists marked and released a total of 15,000 hatchlings in the space of several days. The method—known as “mark and recapture”—allows researchers to estimate the size of an animal’s population, particularly when counting every individual is difficult.

5. An adult Giant South American river turtle. The turtle is the largest member of the side-necked turtle family and grows up to nearly three feet in length. 

For mor information contact: CONTACT: JOHN DELANEY: (1-718-220-3275; jdelaney@wcs.org)

STEPHEN SAUTNER: (1-718-220-3682; ssautner@wcs.org)