Louisiana’s turtles have a price tag on their heads.

Over the past five years, more than 16 million turtles from 20 species have been legally harvested in Louisiana and shipped, alive, to Asian markets, where they are sold as meat,medicine, or pets. Some of the more common species, such as the red-eared slider, sell for a dollar or less per pound. Larger, rarer species, such as the recently protected alligator snapping turtle, have fetched hundreds or even thousands of dollars each.

Other affected species are the common snapping turtle, the river cooter, the Mississippi mud turtle, the southern painted turtle, and five species of map turtle.

Louisiana is the only state that allows unrestricted harvesting of most of its turtle species. Now two conservation groups want to change that. A petition filed last week by the Center for Biological Diversity and the Gulf Restoration Network asks the Louisiana Department of Wildlife and Fisheries to end the unrestricted trade and protect both the turtles and their ecosystems.

“We’re hoping that this petition will push Louisiana toward doing more for their turtles, especially considering the fact that all of the surrounding states, with the exception of Arkansas, have heavily regulated or banned commercial turtle fishing,” said Elise Bennett, reptile and amphibian staff attorney with the Center for Biological Diversity. Florida, Alabama, Texas, and Georgia have all banned or placed strict limits on their commercial turtle harvests over the past nine years.

Louisiana officials could not be immediately reached for comment.

Bennett said this petition isn’t trying to address the hunter who catches the occasional turtle for personal consumption (although she noted that turtle meat can contain mercury, PCBs, and other toxins). Instead, it targets the practice of treating wild turtles as commodities. “Our concern is this market-based approach to managing and conserving turtles,” she said. “Once you’re treating them as a commodity, it’s so easy to just keep fishing them until they’re gone.”

Turtles are especially vulnerable to this type of overexploitation, she said, because they take so long to sexually mature and their eggs and hatchlings have so many natural predators. “They’re not going to replenish themselves if you’re harvesting with no limit.”

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Any decline in turtle populations could also affect the broader ecosystems in which they live. “Turtles connect a lot of the aquatic and terrestrial ecosystems because they eat things in the water and on the land, and other things eat them,” Bennett said. “It’s unclear exactly what would happen if these turtles weren’t in the ecosystem, but it certainly wouldn’t be good. It would impact a lot of other species.”

Some of the captured turtles could end up being dangerous to other wildlife if they escape or are released into nonnative environments. The vast majority of the turtles captured in Louisiana—more than 12.4 million—were red-eared sliders, considered one of the worst invasive species on the planet because of their aggression, voracious appetites and prodigious breeding, not to mention any diseases they can pick up while in the pet trade and carry back to the wild.

One of the broader problems with the trade is that Louisiana only started requiring commercial harvesters to report their catches this past August, so it’s unknown how many turtles are caught in the state annually. The export numbers come from federal data, which only indicates the number of wild-caught animals shipped out of the country. It does not include any turtles that are sold within Louisiana or any that are poached by unlicensed harvesters. It also fails to count any animals that do not survive after being captured.

Bennett said she hopes this petition will inspire Louisiana to regulate and protect its turtle species, a few of which are the subjects of other petitions for protection under the Endangered Species Act. “If we can end this direct harvest,” she said, “that would narrow a lot of the threats affecting these species.”