Smithsonian Science » salamander

Japanese giant salamanders given to the National Zoo by Asa Zoological Park in Hiroshima

John Barrat — Fri, 23 Jul 2010 16:48:31 +0000

The Smithsonian’s National Zoo recently acquired Japanese giant salamanders given to the Zoo by the City of Hiroshima Asa Zoological Park. This donation will be the foundation of a new long-term breeding program in the United States and may play an important role in saving amphibians around the globe. “Our Japanese colleagues at the Asa Zoo have successfully applied decades of work and science to Japanese giant salamanders in the field and at their zoo,” said Dennis Kelly, director of the Smithsonian’s National Zoological Park. “It is an honor for the National Zoo to be entrusted with the offspring from their efforts, and we look forward to collaborating with them to save this magnificent species.”

Japanese giant salamanders live in cold, fast-flowing streams in Japan. Their numbers have been greatly reduced over the years because of agricultural development and habitat modification.

Photo left: Rick Quintero (left), the primary Japanese giant salamander keeper at the Smithsonian’s National Zoo, feeds the Zoo’s new juvenile salamanders for Japanese Ambassador Ichiro Fujisaki (right). Fujisaki was at the Zoo on July 22 to help celebrate the arrival of the salamanders, a gift from the City of Hiroshima Asa Zoological Park. (Mehgan Murphy photo)

“In conserving salamanders, we conserve the ecosystems in which they live,” said Ed Bronikowski, senior curator at the Zoo. “People share those same ecosystems, so what is good for the salamanders is good for many species, including us. We hope our visitors will learn from this generous gift to embrace our own diverse native salamander populations and protect healthy ecosystems for all.”

The National Zoo has experience caring for Japanese giant salamanders since as early as 1940, but with this gift, the Zoo hopes to become the first in the United States to successfully breed this species, which has not been bred outside of Japan in at least 100 years.

During the donation ceremony on July 22, kids from Great Falls Elementary School in Great Falls, Virginia were present to help name one male salamander. The students were asked to choice between two names selected by the ambassador – Hiro, derived from Hiroshima, the salamanders’ home in Japan and Asa, of the City of Hiroshima Asa Zoological Park. Hiro won the student’s vote! –Jessica Porter

Trade in frog legs may spread diseases deadly to amphibians

John Barrat — Thu, 19 Nov 2009 18:25:37 +0000

Most countries throughout the world participate in the $40-million-per-year culinary trade of frog legs in some way, with 75 percent of frog legs consumed in France, Belgium and the United States. Scientists at the Smithsonian Institution and colleagues have found that this trade is a potential carrier of pathogens deadly to amphibians. The team’s findings are published in the scientific journal Frontiers in Ecology, Thursday, Nov. 19.

Photo: Frog legs for sale at a market in Indonesia. (Photo by A. Roselli)

Amphibians are rapidly declining worldwide. More than one-third of the nearly 6,000 amphibian species are threatened with extinction—disease is one of the main causes. Among the known amphibian pathogens, the parasitic fungus Batrachochytrium dendrobatidis, also known as amphibian chytrid (KI-trid), is a top concern. The fungus, which attacks keratin proteins in the skin of amphibians, including frogs, causes respiratory and neurological damage and eventually death.

“Amphibian chytrid is an unusual example of a disease that is a primary cause of extinction in amphibian species,” said Brian Gratwicke, biologist at the Smithsonian’s National Zoo and lead author of the team’s paper. “In fact, amphibian chytrid has been listed as a likely threat in 94 cases out of the 159 extinct and potentially extinct amphibian species. There are several hypotheses about how amphibian chytrid has spread around the world, but the trade in amphibians for food, bait, pets and laboratory animals has been identified as the most likely mode of spread.”

Photo: The American bullfrog is one of the many species used in the frog leg trade. (Photo by Mehgan Murphy)

Although consuming amphibian legs is familiar to many people as a culinary curiosity, the global extent of the international trade is unknown. The team of scientists’ research focused on 1996 through 2006, during which more than 100,000 metric tons of frog legs were imported from both wild and farmed sources, at a net value approaching half a billion dollars. One kilogram of frog legs averaged about $4 over this period—a kilogram of frog legs requires 10 to 40 individual animals translating to approximately 100 to 400 million animals per year.

The scientists found no recorded cases of the extinction of a frog species caused by collection for food. However, given the growing importance of aquaculture to supply frog legs to global markets, the team stresses that the risk of disease spread through poorly regulated amphibian trade is probably an even greater risk to amphibian biodiversity than the direct population effects of overharvesting.

In countries such as Indonesia, which exports about 45 percent of all frog legs, the majority of animals are thought to be wild-caught and there is little to no effort to monitor this food source for disease pathogens. “Any trade in live frogs or fresh, un-skinned frog legs presents a substantial risk of the spread of amphibian chytrid,” said Gratwicke. “The implementation and enforcement of some key amphibian trade policies could be a cost-effective conservation tool to mitigate disease risks associated with the trade.”

Graphic: Global exporters and importers of frog legs 1996 – 2006. Click graphic to enlarge. (Data from the UN Commodity Trade Statistics Database)

The exact origin of amphibian chytrid is unknown, but one theory is that it originated in Southern Africa and was distributed worldwide in the 1950s through the trade of the African clawed frog for pregnancy-testing and other amphibian trade. Amphibian chytrid has been detected in many parts of the United States, but some species are apparently resistant to the fungus, and it is not always associated with amphibian declines. The most dramatic declines have been observed in mountainous parts of Central and South America and Australia where it is responsible for the disappearance and probable extinction of many species.

Study aims to give endangered Shenandoah salamander better odds at survival

John Barrat — Wed, 01 Jul 2009 18:38:52 +0000

Each year thousands of vacationers enjoy the scenery along Virginia’s Skyline Drive, little knowing that for a few brief moments they are passing through the territory of an endangered holdout from the Pleistocene that few humans have ever seen—the Shenandoah salamander (Plethodon shenandoah). Steep rocky slopes on the north sides of just three mountains in Virginia’s Shenandoah National Park make up the scant range of this reclusive amphibian. To see one you’ve got to turn over a few rocks.

Photo: An endangered Shenandoah salamander, left, and a redback salamander, right in Shenandoah National Park. Competition between the two species is believed to confine the Shenandoah’s territory to just a few kilometers.

Its entire habitat is limited to just a few kilometers, a refuge surrounded by vast numbers of the more abundant redback salamander (Plethodon cinereus). How the Shenandoah salamander has managed to survive, and whether they can continue to do so, are questions that have drawn Jennifer Sevin, a biodiversity conservation specialist at the Smithsonian’s National Zoological Park, to the Virginia mountains.

Both Shenandoahs and redbacks are members of a group known as woodland salamanders. Air-breathers who lack lungs, they take in oxygen and expel carbon dioxide directly through their skin. Almost all woodland salamanders live under damp leaves, logs and rocks. At night and on rainy days they come out to prowl for mites, springtails, and similar small fare.

Once more widely distributed, the Shenandoah salamander likely retreated to its higher elevation habitat at the end of the Pleistocene (~10,000 years ago) as Earth’s climate warmed. “Climate change is believed to have allowed the redbacks to expand,” Sevin says. Found in forests from Canada to North Carolina, redbacks also command the wooded areas of moist soil that surround the Shenandoah salamander’s talus patches. Competition between the two species may help confine Shenandoah salamanders to the rocky slopes.

Photo: Jennifer Sevin searches for Shenandoah salamanders on the moist, leaf strewn, forest floor of the Shenandoah National Park in Virginia.

Redbacks are not the only problem for Shenandoahs. Present-day climate change was ranked as the number-one threat to Appalachian salamanders by scientists attending a salamander conservation workshop last May at the National Zoo’s Conservation and Research Center, in Front Royal, Va.

In Shenandoah National Park, construction of the celebrated Skyline Drive in the 1930s may have further isolated Shenandoah salamanders, possibly cutting off gene flow between newly separated populations. Sevin has spent much of spring, summer, and fall the last two years scrambling over the talus slopes of Stony Man, Hawksbill, and the Pinnacles. She is collecting data that will shed light on the competition between salamanders on the three mountains. A nest she found last August containing one mother, six eggs and two hatchlings (the first Shenandoah salamander nest seen by any scientist) was a high point in an intensive project.

Sevin has repeatedly visited 124 study plots, each 32 by 2 meters, some in talus areas and others in less rocky habitat. In addition to measuring and weighing every salamander found, she and her team also note conditions such as air temperature, relative humidity, the amount of moisture on rocks and other objects and days since last rainfall. They also have collected information on each site’s dominant tree species, the amount of canopy cover, the depth of leaf litter, the distance from roads or trails, and the kind of talus present.

Photo: Researchers from the National Zoo take a census of Shenandoah salamanders in the Shenandoah National Park. Global Positioning System coordinates are used to pinpoint the rough boundaries of the salamander’s territory. (Photos by John Barrat)

Zoo scientists are using DNA to learn if Shenandoahs and redbacks are mating across species. “If these species are hybridizing, there is the potential for the redback genes to swamp the Shenandoah salamander genes,” Sevin says. That could bring down the curtain on five million years of Shenandoah salamander history.

In addition to the DNA work and pending permission from the U.S. Fish and Wildlife Service, Sevin hopes to capture approximately 30 Shenandoahs for experiments that will be conducted in climate-controlled rooms in the basement of the Zoo’s Conservation Biology Building. National Zoo biologists want to investigate how climate change might affect the species’ use of habitat, feeding success and even its competition with redback salamanders. Brian Gratwicke, a biologist who leads the National Zoo’s Amphibian Conservation Program, also will attempt to breed Shenandoah salamanders in captivity, something never done before.

Salamanders merit attention “simply for existence value,” Gratwicke insists. “They are important because they existed in this part of the world a long time before we ever got here, and they’re beautiful, amazing creatures.” Reason enough, he believes, to try and help them stick around a few more million years.