It's Alive! It's Alive!
About a year and a half ago, I blogged about how Snakehead fish - an introduced, exotic species - were being found in Maryland waterways in increasing numbers. Snakeheads are an extraordinarily agressive species to both anglers and other fish, so the Department of Natural Resources was vitally concerned about their spread and the detrimental effect they might have on our native fish stocks. The fish can slither on its fins and live on land for up to three days.
Today's Baltimore Sun reports that this war is over and the fish have won. Maryland's snakehead infestation is permanent. About 200 of the critters were caught in a Potomac River tributary recently. "The water is black from these schools of fish," reported one official. When asked whether the DNR hoped to eradicate the fish, the official said, "There is no way. It could never be accomplished if we wanted to. We're not even really trying to reduce the numbers."
So much for draining and poisoning ponds as a precaution. You'd think house sparrows, starlings, kudzu, and zebra mussels would have tipped them off.
K-
I don't think introducing animals, particularly prolific ones with few natural enemies, to a new and unnatural environment is ever a good idea. The mongoose in Hawaii and the nutria in Louisiana are also testament to that.
Find the movie "Cane Toads" if you haven't seen it already -- a semi-comic treatment of a transplanted-species mishap in Queensland, Australia.
As to the fish and stopping them: A few years ago here in Northern California, someone found some one or two northern pike in a reservoir, Lake Davis, along the Feather River. The state decided to poison the lake and kill everything in there -- (planted) trout, pike, whatever. The fear was that the pike, which are voracious predators with no natural enemies here, would get into the rivers and perhaps wipe out the few remaining wild salmon in the state. It was a very unpopular decision with the locals, who depended on Lake Davis to attract anglers and for drinking water.
To cut to the chase: When biologists began checking on the lake the year after they poisoned it, they found more pike. Either they'd survived or whoever had planted the first ones planted more. In any case, now the state has figured we'll just live with them.