Researchers at Oregon State University have discovered a freshwater organism that might help in fighting the chytrid fungus, which is a principal cause for the worldwide amphibian decline. A freshwater species of zooplankton, called Daphnia magna, could provide a tool for biological control of the deadly fungus whose impact, one researcher has called “the most spectacular loss of vertebrate biodiversity due to disease in recorded history.”
Daphnia magna is a variety of water fleas of the genus Daphnia, some species of which are commonly used as food for aquarium fish. It was known that the zooplankton could devour some types of fungi. Oregon researchers wanted to find out whether Daphnia magna could also consume the chytrid fungus that has been devastating amphibian populations worldwide, including Colorado’s endangered boreal toad.
Through extensive research, scientists confirmed that Daphnia magna could consume the free swimming spores of the fungal pathogen. According to lead researcher Julia Buck, an OSU doctoral student in zoology, in an Oregon State University press release:
We feel that biological control offers the best chance to control this fungal disease, and now we have a good candidate for that. Efforts to eradicate this disease have been unsuccessful, but so far no one has attempted biocontrol of the chytrid fungus. That may be the way to go.
Now scientists need to conduct field studies to confirm the zooplankton’s effectiveness in a natural setting. The OSU scientists have found that Daphnia inhabits amphibian breeding sites where chytrid transmission occurs and may be able to stem the unprecedented population declines and extinctions.
For background on the chytrid fungus, please see the video below that we found on the Save the Frogs site, produced by the National Science Foundation:
The Oregon State University research was reported in the journal Biodiversity and Conservation, and was supported by the National Science Foundation. Click here for the full report.
Eating frogs legs is a bit of a joke to Americans. Most of us would never consider eating them. Yet we need to take this very real threat to frogs seriously.
A recent article in Scientific American, “How Eating Frogs Legs Is Causing Frog Extinctions,”* listed some pretty amazing statistics:
Over two thousand metric tons of frog legs are imported into the U.S. each year. Another two thousand metric tons of live frogs are imported every year for sale in Asian-American markets.
The European Union imports an annual average of 4,600 metric tons of frog legs, mostly to Belgium (53 percent), France (23 percent) and the Netherlands (17 percent), the equivalent of about one billion frogs.
The numbers in the Scientific American article come from a recent report, “Canapés to Extinction: The International Trade in Frogs’ Legs and Its Ecological Impact” (pdf), released on July 26 by the wildlife conservation groups Pro Wildlife, Defenders of Wildlife and the Animal Welfare Institute.
According to Alejandra Goyenechea, acting director of international conservation programs for Defenders of Wildlife:
Humans have been eating frogs for ages. But today the practice is not sustainable on a global scale. Billions of frogs are traded internationally each year for human consumption, and that industry is responsible for depleting wild populations, spreading deadly disease, and allowing invasive species to destroy the health of native ecosystems.
This huge demand for frogs legs is contributing to frog extinctions for two reasons:
Too many frogs, collected from the wild, are depleting natural populations
The international trade in frogs legs and live frogs is the major reason for the spread of the deadly chytrid fungus (Batrachochytrium dendrobatidis), which has already been blamed for amphibian extinctions around the globe.
According to the report, most frog and frog leg imports to the U.S. come from China, Taiwan, Ecuador, Brazil, the Dominican Republic, Vietnam, Mexico and Indonesia. One of the species farmed is the Bullfrog, an American native species that has spread around the world. But Bullfrogs are one of the most notorious carriers of the chytrid fungus. According to Save the Frogs, as quoted in the SciAm article:
A recent study estimated that 62 percent of the bullfrogs entering California from Asian frog farms are infected with the chytrid fungus. Bullfrogs serve as perfect vectors for fungus, as the frogs can survive infection loads of millions of chytrid zoospores. Because the infected frogs don’t die from the fungus, they are able to spread the pathogen to native amphibian populations.
Bullfrogs are usually resistant to the chytrid fungus and rarely, if ever, die from exposure to it. Most other amphibian species have an 80 percent mortality rate when exposed to the fungus.
Exact statistics on which species are being imported and eaten are incomplete, because most imports are already skinned, processed and frozen, making them hard to identify.
The three organizations behind this report are now calling for increased regulation of the frog trade under the Convention on Trade in Endangered Species of Wild Fauna and Flora (CITES). That agency has the authority to restrict some hunting and harvesting, create humane standards for frog handling and killing, set monitoring criteria for wild populations, and require that all imported meat be frozen, which would slow the spread of disease.
Last year, the U.S. Fish and Wildlife Service asked for public comments on a proposal to ban the import of live frogs under the Lacey Act, which regulates the import or transport of wildlife species that are either dangerous to humans or the environment. The public comment period ended in December, but so far there is no word yet on if the proposal will become law.
One of our first posts at Frogs Are Green was about the coqui, a frog native to Puerto Rico, where it exists alongside several other species of Eleutherodactylus frogs and where a biological balance is maintained. It was introduced to Hawaii in the mid- to late 1990s and has no competitors so it has spread unchecked and is considered an invasive species. But our guest author, Sydney Ross Singer, a medical anthropologist, biologist, and author living on the Big Island of Hawaii, would like us to look at this problem from a new perspective. Perhaps this “alien” species should not be rejected and destroyed but welcomed.
Besides being beautiful, fascinating, a source of medicinal substances, and essential for healthy ecosystem function, frogs are canaries in the environmental coal mine. They are sensitive to pollution and climate change. And their numbers are declining at extinction rates.
That’s bad news for the rest of us living in the coal mine. Clearly, we need to change our ways.
But change is difficult for a culture to accept. Until people are dying at the rate of frogs, nothing will alter our bad cultural behaviors.
So the next best thing to do is try saving the frogs. We may not be able to stop pesticide and herbicide use, or end the deforestation and development of wild areas, or stop all the industries and lifestyles that contribute to climate change. But we can catch frogs where they are declining and find new, healthier places for them to live.
We might not have the political and economic clout to stop multinational corporations from exploiting and altering the world’s environments. But we can help refugee species flee the destruction and avoid extinction.
There are places on the planet that can serve as sanctuaries for these refugees. One place, in particular, stands out as one of the best – Hawaii.
If you move frogs from one place to another that already has frogs, the immigrants will compete with the natives, and you can possibly lose native frog populations. Hawaii, however, has no native frogs, or any native reptiles, amphibians, land snakes, or lizards. What better place to introduce frogs? Lots of insect pests to eat, warm and humid conditions, and few predators. If we wanted a sanctuary for endangered and threatened frogs, this is the place.
But wait. Can we just move a species from one part of the planet to another? Won’t it become invasive and cause damage?
It is this question that is keeping frogs from finding new homes. According to current trends in environmental thinking, species “belong” where they are “native.” You’re not supposed to move them to places where they “don’t belong.” When it comes to frogs, the Hawaii government has said they clearly “don’t belong.”
Of course, there are already frogs and toads in Hawaii, which were brought by environmental managers for insect control decades ago. Back then species were introduced deliberately to enhance biodiversity and provide needed environmental services, such as pest control, or to serve as a food source. The environment was seen as a garden for us to plant and inhabit as we saw fit.
That has all changed. Now the goal of managers is to kill introduced species in order to preserve and restore native ecosystems as they had existed prior to western contact centuries ago. They won’t get rid of the people, or the agriculture, or the chemical spraying, or the bulldozing, or the deforestation, or the development, or the intercontinental shipping, or the industries and energy policies that help cause climate change. It’s hard to change these aspects of the culture. But you sure can kill things that “don’t belong.”
What was called “exotic” or “immigrant” is now called “alien” or “invasive.” We have gone from an open immigration policy to a bio-xenophobia.
When coqui tree frogs accidentally arrived in Hawaii with shipments of plants from Florida or Puerto Rico, the response was ballistic. The mayor of Hawaii declared a state of emergency. Scientists feared the sky was falling, and that the coquis, which eat lots of insects, would decimate the insect population to the point of starving all other insectivorous creatures. The sound of the frogs, a two-toned “ko-KEE”, was described as a “shrill shriek” guaranteed to keep everyone awake at night, run down property values, and drive away tourists.
Ironically, this same coqui frog is the national animal of Puerto Rico, its native land. In fact, Puerto Ricans love this frog and its chirping sound so much that it is honored in local folklore. People describe the nighttime sound of the coqui as soothing and necessary for sleep, and Puerto Rican travelers often bring recordings of coquis with them when away from home to help them sleep.
Puerto Rico has numerous species of coqui frogs, many of which are now extinct or threatened. Unfortunately, frog numbers are declining because of fungal infections, development, climate change, and pesticide and herbicide use. So you can imagine how angry and upset Puerto Ricans were when Hawaii announced its Frog War to eradicate the newly arrived coquis.
Over the past 10 years, millions of dollars have been spent in Hawaii trying to kill coquis. And despite wide cost-saving cuts in government spending, there is still money to kill coquis.
At first, they tried an experiment to kill coquis with concentrated caffeine, giving the frogs a heart attack. A special emergency exemption was needed from the EPA to allow this spraying of caffeine into the environment. It’s impact on humans, pets, plants, lizards, and other non-target species was unknown, or what it would do once it entered the groundwater and flowed to the oceans. Chemical warfare suits were needed by applicators to prevent exposure to the highly dangerous caffeine, which was at concentrations 100 times that of coffee. There is no antidote for caffeine poisoning.
When the caffeine experiment proved untenable and too dangerous, citric acid was encouraged as a frogicide. Sprayers soaked the forests with acid, sometimes sprayed from helicopters, to drench the tiny frogs and burn them to death. Of course, this also killed plants and other critters, such as lizards. But since lizards are non-native, nobody in the government cared.
But citric acid is expensive. So another experiment was tried, using hydrated lime to burn the frogs. This caustic chemical can also cause irreversible eye and lung damage to people and pets on contact, so another emergency exemption was needed from the EPA to experiment with it. As it turned out, the hydrated lime didn’t work very well, and it killed lots of plants.
So the University of Hawaii experimented on developing a frog disease to unleash on the frogs. They tried a fungus to infect the frogs, the same one killing frogs elsewhere in the world. They realized the fungus might also kill the geckos, skinks, anoles, and other lizards, as well as the toads. But since none are native to Hawaii, none of the eradicators cared. In fact, destroying all the lizards and toads would be considered a plus. The coqui frogs, however, survived the fungus, so it was never released wide scale.
By now you may wonder how people can get away with this abuse of frogs. Aren’t there laws protecting animals from this type of cruelty?
There are. So to get around the laws the Hawaii legislature passed a law defining the coqui as a “pest.” Pest species are exempted from humane laws.
This moral depravity reached its zenith in 2007, with a planned Coqui Bounty Hunter contest to be held by public schools on the Big Island. Schools instructed students to kill coquis, either by burning them with acid, cooking them alive, or freezing them. The school with the most “kills” would receive a prize — the violent video games Playstation 3 and Xbox. The contest was canceled once it was pointed out to the schools that students are supposed to receive humane, not inhumane, education.
Despite the eradication attempts, the frogs spread. Actually, sometimes they spread because of these attempts, since coquis try leaving areas disturbed by spraying. An interisland quarantine on the coqui still exists, requiring all plant nurseries to treat plants with hot water, proven lethal to coquis and their eggs, prior to transport to other islands. But the coquis seem to frequently survive that, too.
So here is the irony. Frogs are disappearing from everywhere in the world except in Hawaii, where the government is trying to make them disappear.
Yet, despite the endless anti-coqui propaganda, people are coming to like the little coqui frog, especially those people who have arrived to Hawaii since the advent of the coqui. To these people, the sound of Hawaii includes the coqui. To these new human immigrants, the coqui is normal, and enjoyable. They understand why the Puerto Ricans love these frogs.
If we are to save the world’s endangered and threatened frogs, and other wildlife that needs rescue from the human-damaged world, we need to change our environmental immigration policy. It doesn’t matter where a species is native, or where it “belongs”. That these species survive is what matters. And this may require finding them a new home.
This is not to suggest that we bring in species willy nilly, without thinking about the impact on local species. We need careful study to know which species can be introduced, and where. But unless we open our borders, and our hearts, to these refugee species, they will die.
We caused their problems. Their fate is in our hands.
ABOUT THE AUTHOR:
Sydney Ross Singer is a medical anthropologist, biologist, and author living on the Big Island of Hawaii. He is an outspoken defender of the Hawaiian coqui frog, has created Hawaii’s first coqui frog sanctuary, and has been featured on Animal Planet, PBS Nature, BBC radio, and Univision. He is co-author of Panic in Paradise: Invasive Species, Hysteria, and the Hawaiian Coqui Frog War (ISCD Press, 2005). His website is www.HawaiianCoqui.org.
We are extremely pleased to feature a guest post by Allystair D. Jones, who studied the canyon tree frog population in Zion National Park, Utah, to determine if the frogs were infected with the chytrid fungus, a disease that is wiping out amphibian populations worldwide. His research will be published by The Utah Academy of Science, Arts andLetters in May 2011.
Chytridiomycosis is an emerging infectious disease that is plaguing the world and causing the extinction of frogs around the globe. This disease is believed to have come from Africa in 1938 when frogs were sometimes used to diagnose pregnancy. This disease is responsible for the extinction of at least 30 populations of frogs and has found its way into Arizona killing the canyon tree frog (Hyla arenicolor). The Chytrid disease can move very quickly and is transferred through water, contact, or even muddy boots from hikers. My research is aimed at watching the population of canyon tree frogs in Zion National Park and as of the summer of 2009 it appeared this population is safe.
Photo by Allystair D. Jones
The geography of Zion National Park is very unique. Zion is the middle step in the grand staircase with the Grand Canyon being the first and Bryce Canyon the last. This made locating the frogs often very difficult and technical rappelling and climbing skills were needed. I have been climbing for more than 20 years so I was especially suited for this study. I travelled through the canyons where this frog likes to live and captured, swabbed their bellies with a cotton swab, and released them back to the location that I caught them. I used the prescribed swabbing techniques and noted the location and time of the swab. I then saved the samples for DNA testing.
Photo by Allystair D. Jones
Photo by Allystair D. Jones
I tested all the samples with a general fungus primer, meaning I tested it to see if there was any fungus at all even if it wasn’t the chytrid fungus. Those that were positive for a fungus were tested for the specific chytrid. The results were very pleasing as none of the samples came up positive for this deadly fungus. This was the first study of this kind done in Zion National Park and during the following year there should be more if the funding keeps up.
Photo by Allystair D. Jones
It was noted in a review journal article at the beginning of this year (Kilpatrick et al 2010) that to help combat this disease we would need to find a viable population of frogs that are not already infected. I submit this population of frogs to be that population, that if monitored with care may help us gain ground in fighting this deadly disease. We need to increase our efforts to learn about this disease.
*KILPATRICK, A. M., BRIGGS, C. J. & DASZAK, P. 2010. The ecology and impact of chytridiomycosis: an emerging disease of amphibians. Trends in Ecology & Evolution, 25, 109-118.
