Bad frogs

Not to mention eels, jellyfish (in Lake Mead!) mussels and a few more of our favorite invasive species

Freshwater Jellyfish
Photo: Colleen Wang

Clawed frogs—they may be the world’s only interesting-sounding amphibian. But they’re also illegal in Nevada—they jack up the ecosystem—and last week state game wardens fined a Florida company $3,600 for distributing them, this after seizing 68 clawed frogs from across Nevada.

There’s nothing like a statewide frog seizure to make you wonder, what other invasive species are screwing up our ecosystem? Here are a few of our favorites:


Beyond the Weekly
Nevada game wardens seize illegal African frogs (Las Vegas Sun, 8/6/08)
Aquatic Animals

8. Freshwater jellyfish

Where it’s from: Yangtze River in China. How’d it get here? Transplanted aquatic plants from China ended up inside fish hatcheries across the country. These dudes were riding along. How invasive is it? Mixed. While populations have exploded across the country, their impact on the ecosystem is unclear. They eat fish eggs under lab conditions, which suggests they could hurt fish populations in Lake Mead. Danger level: Pretty low—it’s only the size of a penny, and its stingers can’t pierce human skin.

7. Snapping turtle

Where it’s from: Children’s aquariums. How’d it get into Lake Mead? Parents and children “freeing” them. Problem: “The wild” for these turtles usually isn’t the Colorado or Truckee rivers. Invasive? Potentially. Snapping turtles compete for food in rivers and streams against native species.

6. Exotic tamarisk plant

Where it’s from: Southeastern Eurasia. When did it get here? 1930s (roughly). How did it get here? Railroad companies imported and used the trees to shore up track banks, thanks to their wide and long root structures, which kept the ground in place. Invasive? It consumes millions of gallons of water a year from the Colorado and similar rivers, provides no nourishment to wildlife and kills other plants with its water-hogging root system.

Spotted Tilapia

5. Spotted tilapia

Where it’s from: Tropical Africa. How’d it get into Lake Mead? Officials say an aquarium release into Lake Mead allowed the fish to grow and become plentiful. Wait, don’t I order that at Mexican restaurants? Yeah, and it’s pretty expensive, too, ironically. Invasive? Tilapia is a very aggressive fish and tends to bully—or eat—native fish into extinction. So if there’s so many of them, my Mexican dish should be cheaper, right? Wrong. Most Tilapia for consumption purposes is imported into the city. Besides, would you really want to eat something that comes out of Lake Mead?

4. American eel

Where it’s from: The Atlantic Ocean. How’d it get into Lake Mead? Generally stocked in the Midwest and South, eels reportedly got into the Colorado River after escaping from an aquaculture facility somewhere on the river. Invasive? It’s unclear how they affect Nevada’s lakes, but the eels, which can get up to nearly 5 feet long, have been known to contain a parasite that can infect fish. What to do if you see one: Swim the other way—it’s a 5-foot eel!

3. Cheatgrass

Where it’s from: Europe and parts of Asia. Accidently introduced into America in the 1800s, cheatgrass has spread across the entire country and blanketed parts of the landscape with a thick, green grass. How’d it get here? Hitching a ride on the backs of bovines and other herded animals in the 1800s. Invasive? Its green exterior dries out and dies, leaving a husk that is the perfect fire-ignition device—it burns fast and hot. So is there any good news? Yep. It doesn’t really exist in developed areas. The bad news: It exists everywhere else.

Walking Catfish

2. Walking catfish

Where it’s from: Native typically to south Asia. How’d it get here? Officials believe they were imported to Florida for the aquarium trade, and aquarium releases are why the fish exists in other states, including Nevada. Can it really walk? Yes, it migrates to other streams by literally walking to them during rainstorms. That’s creepy. It sure is; what’s even creepier is that it invades aqua farms and preys on fish stocks, requiring farmers to erect fences to protect the ponds. The good news: These things have generally failed and died off in Nevada. The bad news: They’re still creepy as hell.

The Quagga Mussel

1. The Quagga mussel

Where it’s from: Originally found in the Ukraine. What is it? The big bad mother of all invasive species, the Quagga mussel is small, reproduces fast and loves pipe and reservoir systems, clogging them up seemingly overnight. How’d it get here? Hitched a ride via ballast water in boats traveling from the Ukraine to the Great Lakes, where it proliferated. In 2007, the mussel was suddenly found in Lake Mead and in various other water areas serviced by the Colorado River, more than likely from a transported boat that ended up in Lake Mead. Why does it scare the hell out of biologists? Its high reproduction rates damage pipe systems; it can kill off endangered fish in the ecosystem by consuming resources and via water-flow obstruction. Worst of all, it’s evolving faster than can be charted. What’s even worse: There are fears that Quaggas could get into the intake pipes at Lake Mead, potentially destroying the water intake system, sapping the valley of water and costing millions of dollars to repair. Is there a bright side? No. Quaggas are enemy No. 1 for biologists regionally. And worst of all, they’re not even edible.


Aaron Thompson

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