![]() We also don't have bears in this area, so the fish get to a size where the only primary predator is going to be a human. But once the fish grow above around five pounds, it's difficult for herons or eagles to pick them up. There are birds that consume them, as well as some large catfish. Snakeheads also grow so fast that they escape a lot of predators. I've cut open a lot of bass and never found a snakehead in their guts. Young snakeheads are certainly susceptible to predators, although both parents guard them closely. We haven't seen major impacts on prey species, perhaps because snakeheads eat such a diverse diet, from other fish species to invertebrates and even small mammals. ![]() For the most part bass seem to be holding their own, although we did find a dominance of snakeheads in one tributary we sampled in Virginia, where we found only a few small bass. Snakeheads can commonly grow up to 10 or 12 pounds (with 18 pounds being the record), while bass might get to 3 or 4 pounds, and both fish occupy the same niche as opportunistic, top-level predators. Snakeheads reproduce twice a year and both parents closely guard their offspring, which is unusual for our fish fauna, and that has led to high levels of survivorship.Īnglers have feared that snakeheads will outcompete largemouth bass, which were introduced into the Potomac River in the late 1800s. People weren't too concerned about them spreading, but that did happen. What impact are the fish having on the environment here?Īt first people were concerned that snakeheads would cause extinction of local species, but that hasn't happened. Some people have speculated that all the attention made people who already had the fish nervous, causing them to ditch their pets into rivers, although we don't have any evidence of that. ![]() The fish were killed but the incident got major coverage in the media and led to laws prohibiting the importing or keeping of live snakeheads. ![]() Officials treated the pond with Rotenone, a poison that affects the respiratory system of the fish. It wasn't just one fish that was released. So they released the fish as a token of thanks. The fish was introduced there by a family as a symbolic gesture, because a woman had been suffering from an illness and then became better. In 2002, four adult snakeheads and at least a hundred juveniles were found in a pond in Crofton. What happened in Crofton, Marlyand in 2002, leading to widespread fear and, eventually, even a cartoon ? Since then it has spread rapidly through the Potomac. The first snakehead was caught in Doe Creek in Virginia in 2004. The other is that people were keeping them for food but then released them. One is something called prayer release, when people release the fish as part of a cultural tradition. Why they were introduced is somewhat of a mystery, although there are two main theories. How did invasive snakeheads get into the Potomac River?īased on genetic evidence, we believe the fish were repeatedly introduced into the Anacostia River. We spoke with Joseph Love, a fisheries biologist with Maryland's Department of Natural Resources who has studied snakeheads in the region. On May 21, Maryland will host a snakehead fishing "derby" to raise awareness about the invader and encourage the public to be vigilant. State and federal laws also now prohibit keeping or transport of live snakeheads. State officials are working with fishermen to keep the population in check and try to prevent it from spreading even farther. Now they pose a risk to the embattled wildlife of the continent's largest estuary, but people are fighting back. The invasive species were imported legally from Asia for the aquarium and seafood trades until 2004. Growing up to 18 pounds (8 kilograms) and three feet (one meter) long, the "Frankenfish" keep spreading they have recently been found above Great Falls in the C&O Canal (north of Washington, D.C.), as well as in the upper Chesapeake Bay. The northern snakehead has established itself firmly in the Potomac River system, with a population estimated at somewhere above 21,000 individuals, ranging through more than 120 river miles (200 kilometers). Since then, those fears have proven to be only partially correct. People feared the big, voracious Asian fish would gobble up native species and take over local waterways. ![]() When snakeheads were first discovered in a pond in Maryland in 2002, the public panicked. ![]()
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