Zander fish (Sander lucioperca)
Zander fish (Sander lucioperca) (Photo: Kletr/Shutterstock)

You've heard of endangered species and invasive species, but what about injurious species?

This lesser-known classification is a function of the Lacey Act of 1900, one of the oldest conservation laws in the United States. Over the years, the act has played a pivotal role in ensuring the health and welfare of humans and native species as well as safeguarding the interests of agriculture, horticulture and forestry. How? By controlling the trade of nonnative animal and plant species that pose an ecological threat to the local wildlife and natural resources.

When a species is listed as injurious under the Lacey Act, it authorizes divisions of the Department of the Interior, such as U.S. Fish and Wildlife Service, to regulate or ban the importation or transportation of that animal or plant within the U.S.

Species are evaluated and added on a rolling basis. Most recently, the USFWS announced that almost a dozen nonnative freshwater fish have been evaluated and added to the list of injurious species. The species include zander fish (pictured above), Prussian carp, crucian carp, Eurasian minnow, Nile perch, Amur sleeper, stone moroko, wels catfish, European perch, common roach and the common yabby crayfish (pictured below).

Common yabby (Cherax destructor)
Common yabby (Cherax destructor) (Photo: GOLFWORA/Shutterstock)

"The 11 species have the potential to become highly invasive if introduced into the wild in the United States and cause harm to our freshwater habitats and our native species, as well as to the local economies these natural resources support," according to a statement issued by the USFWS. "Therefore, the Service is taking this proactive step to keep these species out of the country before they have a chance to become invasive."

In Oct. 31, 2016, all importation and interstate transport of these marine creatures will be prohibited, unless granted permits for authorized "scientific, medical, educational or zoological purposes."

Since all 11 fish have either never been introduced into the country or have only been imported in negligible numbers, the ruling is not expected to have any impact on businesses involved in the trade of these species.

Europe's fire salamanders (Salamandra salamandra) are in the midst of a mycological crisis.
Europe's fire salamanders are in the midst of a mycological crisis. (Photo: Marek R. Swadzba/Shutterstock)

While many invasive species are classified as injurious, it's important to point out that not all injurious species are automatically invasive. While the problems caused by invasive animals and plants can be incredibly damaging, an injurious species doesn't necessarily have to proliferate in massive numbers to be catastrophic for the ecosystem it invades.

For example, the import of Asian salamanders has been banned due to a lethal and highly contagious fungal disease known as Batrachochytrium salamandrivorans (Bsal) that is currently devastating Europe's once-thriving populations of fire salamanders (like the one pictured above)

Curious to learn what other species are listed as injurious under the Lacey Act? Here are just a few critters that made the list:

Fruit bats

Bats are the only mammal capable of true flight.
Bats, like this large flying fox (Pteropus vampyrus), are the only mammal capable of true flight. (Photo: Erik Zandboer/Shutterstock)

Also known as "flying foxes," all 60 species of the Pteropus genus were listed as injurious on May 25, 1900, the same date the Lacey Act was signed. The bats are not native to the Americas, and they can found through the lush tropics of Asia, Australia and East Africa. They are labeled as injurious because the Lacey Act also regulates the importation of wild birds and mammals, animals that could be considered invasive but aren't yet.

Zebra mussels

Zebra mussel (Dreissena polymorpha)
Zebra mussel (Dreissena polymorpha) (Photo: Vitalii Hulai/Shutterstock)

Named for the vivid striped pattern on their shells, zebra mussels are a freshwater species that was originally native to Russia. In recent decades, they've been introduced to North America, where they have become invasive to the Great Lakes and the Hudson River, clinging to any available surface and eating algae that would otherwise feed fish.

Brushtail possums

Brushtail possum (Trichosurus vulpecula)
Brushtail possum (Trichosurus vulpecula) (Photo: Jamen Percy/Shutterstock)

While these furry Australian marsupials have yet to invade the United States, they were listed as injurious in 2002 as a preventative measure. Listing injurious animals before they become a serious threat is the most effective way to control potentially devastating invasions.

In New Zealand, the animals are considered a pest because of their appetite for new growth on trees. In some areas they have eaten whole canopies, according to the Department of Conservation of New Zealand.

Reticulated python

Reticulated python (Python reticulatus)
Reticulated python (Python reticulatus) (Photo: teekayu/Shutterstock)

Native to southeast Asia, the reticulated python is the world's longest snake. It was declared "injurious" by the USFWS in 2015 due to its invasive spread, alongside the DeSchauensee’s anaconda, green anaconda and Beni anaconda. Together these creatures have been changing the landscape of the Florida Everglades.

European rabbits

They may look cute, but European rabbits can cause serious damage.
They may look cute, but European rabbits can cause serious damage. (Photo: Rudmer Zwerver/Shutterstock)

When introduced in non-native environments, wild European rabbits wreak havoc on vegetation, which can affect the welfare of local wildlife. In the 19th century, a couple dozen European rabbits were introduced to Australia, and due to the lack of natural predators and the mild winter climate, they soon multiplied and spread across the country.

Catie Leary ( @catieleary ) writes about science, travel, animals and the arts.