A toothy jowl snaps shut; behind it, a spear-shaped body writhes to the surface of a stagnant pond. An angry hiss escapes from this ancient-looking fish, a northern snakehead (Channa argus). It has just been electrocuted with a backpack-mounted, gas-powered shocking apparatus, and is now in the grasp of fisheries scientist Paul Overbeck. "That one sneezed," Overbeck jokes, scooping the fish into a net. The nearly 60-centimeter-long fish isn't dead, but it doesn't have long for this world. Overbeck, with colleagues David Keller and Shane Moser from the Philadelphia Natural History Museum's Patrick Center for Environmental Research, regularly collects snakeheads with the goal of knocking back numbers of the invasive species while studying its impact on native fish populations.
Snakeheads, which are native to Asia, were first found in 2004 in this concrete-bottomed, one acre pond—euphemistically dubbed Meadow Lake, located in South Philadelphia's Franklin Delano Roosevelt Park.
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