In a new announcement, the Missouri Department of Conservation (MDC) is reminding anglers that northern snakehead fish are prohibited in the state and it’s illegal to import, export, buy, sell, or possess the fish. In fact, if you happen to encounter one in the wild, the MDC advises killing it immediately by cutting off its head and gutting it.

Here’s what they instruct if you catch a northern snakehead in Missouri:

• First, be sure it’s a northern snakehead because they can be confused with the native bowfin. They can be recognized by their snake-like appearance and a notably longer anal fin compared to the bowfin.
• Never release the fish or leave it on the bank. The species can survive out of water and may wriggle its way back or even reach another body of water.
• Take a clear photo and record the exact location where the fish was caught.
• Kill the fish by cutting off its head, gutting it, or sealing it in a plastic bag.
• Report any catches and sightings of the fish here: https://mdc.mo.gov/fishing/protect-missouri-fishing/snakehead-fish-reporting

“Northern snakehead fish are highly invasive and could reduce populations of the sportfish Missourians love to catch. Anglers can provide us valuable information on the location of this species by reporting captures,” Angela Sokolowski, an Invasive Species Ecologist at the MDC, said in a statement.

The USGS has previously published similar advice for captured snakehead fish in the wider country. Instead of decapitation, though, they recommend killing the fish by freezing it or putting it on ice for an extended length of time. Regardless of the method of killing, most US wildlife authorities stress that the fish should not be returned to the wild alive. 

The northern snakehead fish (Channa argus) is an invasive species that is not native to North America. Naturally found in the lakes and ponds of Russia and East Asia, the freshwater species has managed to arrive and thrive in the US over the last two decades, using their highly aggressive behavior to hunt native wildlife and outcompete local predators. 

The species were being sold in pet stores, markets, and some restaurants in several major US cities, which likely explains how they entered the country.

With a head that closely resembles a snake, this fish lives up to its name in both appearance and behavior. Its body can grow up to 1 meter (3 feet) long, cloaked in python-like patterns that enhance its reptilian look. It can even wriggle across the land like a snake. Although technically a bony fish, it can breathe air, allowing it to survive in oxygen-poor waters. It can even live out of water for several days as long as its skin remains moist. 

They were first documented in the US during the summer of 2002 when a fisherman caught a live specimen at a pond in Crofton, Maryland. Biologists were promptly dispatched to Crofton Pond and filled it with piscicide (a substance poisonous to fish). This clearly wasn’t the end of the story, though. The team found the pond was home to thousands of juvenile snakeheads and it was later apparent that the population wasn’t limited to the local region. 

Missouri may be sounding the alarm now, but established breeding populations of the fish already exist in several other US states, including Virginia, Maryland, Pennsylvania, and New York.

As a highly aggressive and invasive species, the spread of northern snakeheads has raised fears about their potential impact on native ecosystems. However, the extent of that impact remains unclear. Ecosystems are incredibly complex, and it’s often difficult to gauge how they’re responding to disruptions like the introduction of a new species.

This uncertainty has sparked some debate, with some critics questioning whether the KILL KILL KILL, zero-tolerance stance on northern snakeheads might not be totally necessary. Still, for now, authorities seem to agree that the potential risk isn’t one worth taking.