Sun Q&A: Dennis O'Brien on northern snakeheads

Reporter answers readers' questions about voracious Asian predator fish

May 04, 2004

Glenn, Jessup: Do you think the gentleman that caught the fish is pulling a hoax? I do.

O'Brien: I don't think so. Keep in mind the fisherman was with a friend at the time, and that at least one other person apparently saw the snakehead lakeside on the ground before it was turned in. staff: Should we expect to see snakeheads pop up in another Maryland community in the near future?

O'Brien: I hope not, but it's a possibility. While federal officials banned importing snakeheads in 2002, someone could still have one, purchased from either a fish market or a pet store. Biologists believe they can live up to eight or nine years.

Mac, Towson: Where do these northern snakehead fish come from? They're not native to Maryland, so how'd they get here?

O'Brien: They were brought into the U.S. for sale in live fish markets that cater to Asian immigrants. No one is sure when they first arrived, but they were sold for years in New York City. While its illegal to import them into the U.S., they're still being sold in fish markets in Canada.

Bill, Baltimore County: I can't believe the snakehead tried to bite a man's boot! Why is this fish so aggressive? What makes it so?

O'Brien: It's protecting itself in a stressful situation. While unusual, such reactions aren't unique. A northern pike also will snap.

L.S., West Towson: Why drain that lake in Wheaton? Why not just shock it and let it be until someone catches another snakehead? I thought they said someone admitted putting the snakehead in there. Seems like a lot of money to spend draining a lake [and] moving fish to finally get rid of one fish. How much did it cost to drain the lake?

O'Brien: It cost $10,000 to drain and refill the lake. If left alone, there was a chance the fish could have spawned and its eggs spread to connecting waterways downstream, which include the Anacostia and Potomac rivers. Electro-fishing is not effective because it doesn't catch every fish. Draining was seen as a better option than applying rotenone, a poison dumped in the ponds infested in Crofton in 2002. Unlike the lake in Wheaton, the Crofton ponds were full of vegetation and snakeheads and eggs could have hidden in it, making draining less effective in that case.

Mike, Westminster: How fast do snakeheads move on land?

O'Brien: Scientists generally aren't sure. The best estimate is that they make a slow crawl. Some tropical and subtropical species of snakeheads are actually capable of hopping. Among the northern species, it's only the juveniles -- those less than a foot long -- that will crawl.

Debbie, Edgewood: It is interesting reading about snakeheads, but why should I care?

O'Brien: As aggressive predators, they feed on other fish, can wipe out other species of fish and can spread to connecting waterways. Up to 90 percent of their diet is other fish. It's a perfect example of how an invasive species can overtake and destroy a habitat when it has no natural predators.

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