Walking Fish Threatens Region's Waterways

April 10, 2008

Release from: Leah Zerbe
NBC 10 (Philadelphia)

It is a face only a mother could love, and a fish that has environmentalists worried.

The northern snakehead fish, a native of China, was once imported to the United States but was banned because of its prolific and aggressive behavior.

"They live in areas with low oxygen and are good predators," said Rick Horowitz, of the Philadelphia Academy Of Natural Sciences.

Fishermen are also worried because the aggressive fish will eliminate fish native to this part of Pennsylvania.

"At one time, we used to catch a lot of white perch, but I don't see a lot of them now," one fisherman said.

Another unusual characteristic that worries scientists is that the snakeheads can walk.

Experts fear the invaders will swim or walk to the nearby Delaware River and spread to other waterways.

Philadelphia's Academy of Natural Sciences has been conducting a fish survey in lakes and ponds of FDR park, using electric shocks to temporarily paralyze, catch, survey and release the fish.

"It basically puts their muscles in paralysis and allows us to pick them up safely," academy scientist Paul Overbeck explained. "They will revive in a minute or two."

When the scientists put the current into the water, stunned fish of all types float to the surface.

Shad, sun fish, bluegill, carp and and increasing number of snakeheads pop up.

In southeast Asia, snakeheads are considered good eating, but in the Delaware Valley, they are considered a massive threat to local ecosystems.

When the scientists finish their survey, everyone will have a better idea of how big the threat actually is.

What to do to control their numbers is still an unanswered question.