Tuesday 4 June 2013

‘Frankenfish’ may not be a threat, after all

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MOUNT VERNON (Virginia)  They’re freakishly strong, hungry air-breathers that can survive for short periods on land. But northern snakehead fish, once viewed as an unstoppable scourge in US waters, may have gotten a bad rap.

So far, they’ve surfaced in waters from Massachusetts to California, and from Manhattan’s Central Park to a pair of creeks in Arkansas. The biggest cluster is in and around the Chesapeake Bay, and officials in Maryland and Virginia have taken different paths to trying to keep them from interfering with the bay’s delicate ecological balance.

The threat of the snakehead, which is believed to spawn repeatedly during the year unlike other species that spawn just once, is that it is such a hardy newcomer that it could squeeze out longer-established and more desired fish.

Native to China’s Yangtze River basin, the so-called frankenfish made its first big media splash in the United States in 2002, when a thriving population was discovered in a Maryland pond outside Washington. 

Known taxonomically as Channa argus or ‘lightning perch’, they were purported to be able to ‘walk’ on land, to wipe out native species and to have no natural predators. 

Plenty of other non-native fish have thrived in the United States, but few rival the northern snakehead: as long as 76cm or more, the fish has a large, toothy mouth and can survive for days out of water, squirming and secreting a full-body slime. It is a delicacy in Asia and is gaining a following among chefs in the United States.

Virginia fisheries biologist John Odenkirk said intelligent management - not eradication - of the snakehead is his state’s goal. So far, the fish have not wreaked havoc with the Potomac River ecosystem, he said on a recent survey trip through Virginia streams.

The snakehead population has risen since 2004. But so has the population of large-mouth bass, a prized regional sport fish that brings in $622 million a year to Virginia and accounts for more than 5,500 jobs in the state, according to the American Sportfishing Association.

John Rorapaugh, director of sustainability at ProFish, a Washington seafood wholesaler, said his company pays $4 to $5 a pound for snakeheads, compared to $.50 to $1 for catfish.

Snakeheads’ numbers are increasing, even as myths about them are dispelled. Media reports of them “walking” are exaggerated, though they can slither onto land. 

And Odenkirk dismissed the notion that they have no natural predators. Snakehead young, if left unguarded, are easy prey for ospreys and eagles, he said.

Odenkirk said it is still unclear how damaging snakeheads are to their US environments. Paul Angermeier, a fisheries research scientist at the US Geological Survey, agreed. 

“It’s still quite early,” said Angermeier, who is based at Virginia Tech. “A decade or so isn’t long for an invading population to really wreak havoc on things.” So far, that hasn’t happened, he said.
  
 
 
Source:  Omantribune

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