Environmental police are moving today to poison a menacing colony of snakehead fish in an otherwise tranquil Crofton pond. Even if the predatory fish are wiped out, a larger struggle against invasive species will be far from won.
Maryland faces uphill battles with dozens of destructive alien organisms.
Multiflora rose, tree of heaven, Vietnamese stiltgrass, mile-a-minute, purple loosestrife, gypsy moths and garlic mustard might not seem as exciting as an air-breathing, ground-traveling fish that can grow to the size of a golf bag, but experts say they are changing the face of Maryland's landscape as they crowd out native wildlife.
On the ecologically fragile Chesapeake Bay, the oyster fishery has been dangerously depleted, in part by a parasitic disease called MSX that arrived in the region with Asian oysters in the 1950s.
Meanwhile, nutria, large rodents brought from South America decades ago to support the fur industry, are eating their way through the vast marsh that provides food and shelter for tens of thousands of waterfowl at the Blackwater National Wildlife Refuge.
Elsewhere around the bay, natural resource experts are struggling to limit damage caused by alien species as diverse as mute swans, phragmites and water chestnuts.
More trouble appears to be on the way by trains, boats and planes that carry countless containers across the nation and around the world into Maryland every day. State environmental officials are worried about 17 "red alert" species that are not established here but could hammer the state soon.
Among them are zebra mussels, which clog water pipes and boat engines; Asian longhorned beetles from China, which might wipe out forests; red imported fire ants, which pack an extraordinarily painful sting; spiny water fleas, which starve small fish and others up the food chain; giant salvinia plants, which congest lakes and ponds; and plum pox, a virus that can ruin peach orchards.
"It's a monumental challenge," said Glenn Therres, associate director of the Wildlife and Heritage Service at the state Department of Natural Resources.
In February, representatives of state, federal and nonprofit groups working together as the Maryland Invasive Species Council released an updated list of 75 invasive species of concern.
Some are regulated by state or federal law, while others are not regulated but made the list because biologists and natural resource managers recognize their negative environmental and economic effects.
