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Should California Ban American Bullfrogs?

The views expressed are those of the author and are not necessarily those of Scientific American.

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American bullfrogSanta Cruz County in California could soon become the first county in the U.S. to ban the import, sale and possession of American bullfrogs (Rana catesbeiana). Last week, Santa Cruz County Board of Supervisors Chairman Mark W. Stone sent a letter to the board urging it to enact a ban in 2012. Stone’s request followed a similar letter to the supervisors from the chair of the county’s Fish and Game Advisory Commission.

Bullfrogs pose several threats to the native amphibians of California, many of which are endangered. When bullfrogs—the largest frogs in North America—escape or are released into the wild, they have a tendency to eat other amphibians and any other wildlife that will fit in their mouths. Their size also allows them to outcompete native species for food. Even worse, a large portion of the bullfrogs imported into this country—62 percent according to one study—are infected with the deadly chytrid fungus (Batrachochytrium dendrobatidis), a lethal skin disease which has already been blamed for extinctions of about 100 amphibian species around the globe. Bullfrogs themselves are relatively resistant to the chytrid fungus, but that doesn’t stop them from spreading it to other species in the wild.

Bullfrogs are native to the eastern U.S., although the millions imported into California every year come mostly from China, Vietnam, Taiwan and Mexico, where they are farmed for sale as food or pets as well as for dissection in schools. (See my previous story, “How Eating Frogs Legs Is Causing Frog Extinctions.”) According to the Global Invasive Species Database, American bullfrogs have been introduced in more than 40 countries on four continents and are “responsible for outbreaks of the chytrid fungus found to be responsible for declining amphibian populations in Central America and elsewhere.” The database is published by the Species Survival Commission of the International Union for Conservation of Nature.

In his letter, Fish and Game Advisory Commission chair Russel Maridon acknowledged that it is unusual for a county rather than a state to attempt such a ban, but it is necessary because of inaction at the state level. “We recognize that it is more appropriate for this regulatory action to occur on the state level,” the letter read. “While the State of California Fish and Game Commission has twice voted ban the importation and sale of bullfrogs, the Department of Fish and Game still allows it.” (The state commission, in theory, sets policy for the state department, but the department does not have to follow all of the commission’s decisions.) “Therefore—in addition to initiating development of language to ban bullfrog importation and sales in the County—we also encourage the [Board of Supervisors] to contact California Secretary of Natural Resources John Laird to communicate its concerns about this matter and ask that he review the state commission’s relative inaction on this matter.”

The initial request to ban bullfrogs came from the nonprofit Save the Frogs, which is based in Santa Cruz and has actively pushed to regulate the species in the state. “This type of legislation is already in effect for other known, injurious, invasive species in California,” says Kerry Kriger, founder and executive director of Save the Frogs, who notes it would just take adding the American bullfrog to the existing list of amphibians banned in California to end all imports and sales. “We’re hoping to set a precedent in this county and use it to educate politicians and raise awareness throughout the state.”

Endangered amphibians present in Santa Cruz County include the Santa Cruz long-toed salamander (Ambystoma macrodactylum croceum), California tiger salamander (Ambystoma californiense) and California red-legged frog (Rana draytonii). Bodies of all three species—along with the endangered giant garter snake (Thamnophis gigas)—have been found in the stomachs of American bullfrogs in the county.

Photo: American bullfrog by Carl D. Howe via Wikipedia. Used under Creative Commons license

John R. Platt About the Author: Twice a week, John Platt shines a light on endangered species from all over the globe, exploring not just why they are dying out but also what's being done to rescue them from oblivion. Follow on Twitter @johnrplatt.

The views expressed are those of the author and are not necessarily those of Scientific American.

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  1. 1. Eric Mills 2:05 pm 12/13/2011

    Thank you, Mr. Platt, for spotlighting this issue. I only wish the proposed Santa Cruz County ordinance included a ban on the importation of ALL live frogs and turtles for human consumption, as we’ve been urging the State Fish & Game Commission to do since the mid-1990′s. The exotic pet trad is a serious problem, too. At the time, the Commission received more than 2,000 letters in support of the frog/turtle ban, from sporting and environmental groups, and the general public. Senators Sheila Kuehl and Byron Sher wrote, as did Huey Johnson, former Resources Secretary, all to no avail.

    California annually imports some two million American bullfrogs (commercially raised) and 300,000-400,000 freshwater turtles (mostly red-eared sliders and softshells), all taken from the wild, depleting local populations. None are native to California, and when released into local waters (a common practice among certain religi9ous sects and “do-gooders”), the exotics prey upon ande displace our native species. (I have photos of bullfrogs eating baby ducks and baby western pond turtles.)

    Worse, all the market frogs and turtles are diseased and parasitized. We’ve had 25 necropsies done, showing E. coli, salmonella, pasturella, giardia, blood parasites, even one case of malaria. Bon appetit. IT IS ILLEGAL TO SELL SUCH PRODUCTS FOR HUMAN CONSUMPTION, YET THE COMMERCE CONTINUES UNABATED. The chytrid fungus issue alone should be enough reason to stop the trade, no? Many of the market animals are butchered while fully conscious.

    As usual, it’s more a matter of “bad politics” than “good science.” Only weeks after the Commission voted unanimously for a ban on the frog & turtle imports, the Director of Fish & Game, John McCamman (now departed), announced that he would continue the permits on a month-to-month basis. Challenged by an irate Commission, DFG Deputy Director Sonke Mastrup responded, “The Director acts at the pleasure of the Governor.” So much for the democratic process. (Interestingly, Mr. Mastrup is now Executive Director of the Commission. Can you spell “conflict of interest”?) And in a 11/21/11 LOS ANGELES TIMES article by reporter Louis Sahagun, Mr. Mastrup is quoted as saying, “This is about a cultural practice, and the Department doesn’t like getting in the middle of those things.” Amazing. And not acceptable.

    Hopefully, Resources Secretary John Laird will save the day, should the Department continue to ignore its mandate. I would urge your readers to contact Secretary Laird (a former Santa Cruz Assemblyman), and urge him to stop the importation of all live frogs and turtles for human consumption. He has the authority.

    John Laird, Secretary, NATURAL RESOURCES AGENCY, 1416 Ninth Street, #1311, Sacramento, CA 95814. Tel. 916/653-5656; fax 653-8102; email –

    Eric Mills, coordinator
    email –

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  2. 2. spcaLApresident 10:56 pm 12/14/2011

    It is inexcusable that the California Department of Fish and Game has simply abdicated it’s responsibility to protect California’s native species. It is shameful that a city, will try to solve this problem while the state stands idle. It is criminal to permit the sufferings and decimation of species local and imported. It is time to stop it once and for all.

    Link to this
  3. 3. paw pac 12:50 am 12/15/2011

    Fish and Game allowed the importation and release of non native turkeys for hunting until they were sued to stop it and has resulted in depredation permits and turkeys all over the state now considered a nuisance. They continue to love hunting non-native wild pigs who were brought here for hunting with devastating effects. Their allegience is to hunting and abdicating to politics on the issue of importation, and their inevitable release, of millions of frogs and hundreds of thousands of turtles for the live animal markets.

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  4. 4. tmsteiner 3:17 pm 12/15/2011

    We urge the State of California to ban the import, sale and possession of non-native frogs and turtles to protect CA native biodiversity. In addition to protecting CA wildlife, it may reduce market forces that encourage the removal of these species from the wild populations where they are hunted.

    Todd Steiner
    Executive Director
    Turtle Island Restoration Network
    PO Box 370
    Forest Knolls, CA 94933 USA

    Link to this
  5. 5. turtle 5:45 pm 12/15/2011

    California Fish & Game Commission is really comprised of many hunters and fisherman who really do not give a heck about the turtle and frog population that has been decimated by non-indigenous species. We have tried for many years to get them to enforce a ban in live food markets where many of these animals are brought in from other states and other countries. Of course, they get loose and end up in our waterways. While many of us beg at every meeting, nothing has been done for 16 years. Now all the native turtles and frogs are on their way to being extinct in California. Nice work Fish & Game. Thanks for nothing. American Tortoise Rescue, Malibu CA

    Link to this
  6. 6. Eric Mills 7:28 pm 12/15/2011

    This just in from WILDLIFE ALIVE:

    Bullfrogs simply do not belong in California. Many native species of fish and amphibians appear to suffer considerably from competition and predation by bullfrogs, including many endangered species of limited habitat. A ban on importation is an important start in removing bullfrogs from our California ecosystems.

    Mark J. Palmer, Director
    A subproject of Earth Island Institute

    Link to this
  7. 7. jkodiak 7:37 pm 12/15/2011

    It’s amazing to me that we are allowing our native amphibian populations to be decimated just so markets in Chinatown can continue to sell frogs as food. I applaud Santa Cruz County for taking the lead on this issue. Fish and Game needs to step up and do their job.
    Patrick Schlemmer
    President of the San Francisco Naturalist Society

    Link to this

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