This snakehead fish can survive on land and it's so invasive, scientists say kill on sight

The northern snakehead , an eel-like fish with extremely pointed teeth that is native to Asia, is quickly taking over the rivers and lakes of the United States. The highly aggressive fish is a serious threat to native wildlife and aquatic life. Initially discovered in a pond in Maryland in 2002, the species has now been found in other locations, such as the Potomac River, Pennsylvania, and most recently, Missouri.

Angela Sokolowski, Missouri Department of Conservation invasive species coordinator, warned that "These fish are out of their native range, where predators and prey balance each other out. Here, they can grow quickly, reproduce rapidly, and outcompete natives for food and space."



Northern snakehead features


The most unsettling feature of the northern snakehead might be that it can breathe air. In contrast to the majority of fish, this adaptation enables it to live in conditions with low oxygen levels and even out of water all together. Sokolowski warned the snakehead's longevity is the problem: "These fish will survive for days on a cooler of ice… so we're asking anglers to actively kill them so that they won't unintentionally believe those fish could be dead and then unintentionally release somewhere else."

Adding to the challenge, northern snakeheads can slither across land in search of new water bodies. This ability makes tracking and controlling their spread especially difficult. As Sokolowski noted, “They can hide in muddy, vegetative wetlands, even when we’re trying to find them, and remain out of sight.”




Northern snakehead becomes most active this season


Spring is a good time to search for northern snakeheads due to their breeding pattern. In those months, the fish can be seen with others being protected by them. "The female and male will defend the very young fish, which are known as fry. They hug their backs to the fry and keep them in a tight clump like a group, and it looks like a ball of baby fish. We call it a fry ball," Sokolowski said.

The snakehead will become aggressive when it is defending its fry. They have been caught by fishermen while fishing for other species, as the snakeheads will attack anything ferociously that they feel might be a threat to their fry ball.




How the northern snakehead made its way into US ecosystems


The snakehead likely entered US waters through two principal means. Some were imported for the live fish market, where they were sold as food. Others came in through the aquarium trade. Either by accident or on purpose, some were released into the wild, and the species began to adapt and spread through new habitats.

State wildlife officials now urge anglers and the public to assist in keeping the northern snakehead invasion at bay. Understand that it doesn't necessarily involve putting a caught snakehead in ice. Authorities advise that the fish be killed by decapitating or gutting it. Otherwise, it can be put in a plastic bag and thrown away as trash. Sokolowski states, "I guess it's personal preference," regarding the process of euthanizing the fish, but whatever is done is intended to keep the species from breeding further.



Snakeheads now found in city parks, not just remote waters


It's best to err on the side of caution and not mistake the northern snakehead for native species like the bowfin. The Missouri Department of Conservation recommends that snakeheads have a more pointed anal fin and have a very distinctive snakelike look, so they're relatively easy to distinguish. Unlike it was expected, snakeheads are not only limited to isolated regions. They have also been found in highly populated urban areas, such as Central Park Harlem Meer and Flushing Meadows Corona Park lakes in New York City. Such urbanization necessitates that the species be addressed with urgency.

As conservationists like Sokolowski point out, sport anglers play a key role in eliminating the northern snakehead. Sport anglers can play a pivotal role in stopping the invasive predator's wider distribution through watchfulness and submitting encounters or catching and eliminating the fish.





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