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Chesapeake Region Officials Hunt Down Invaders |
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 By Bay Journal Staff
Virginia has issued a wanted poster. Maryland has issued a death warrant. Pennsylvania is on the hunt.
Across the Chesapeake region, state officials are hunting down non-native invaders. The wanted include nasty little fire ants, snakehead fish, elegantly named emerald ash borers and inelegantly named rock snot – a.k.a. Didymo, the name polite scientists call the microscopic algae sliming rocks in mid-Atlantic rivers.
All are wanted for endangering local ecosystems, and most are common to all the states in the Chesapeake region.
The Virginia Invasive Species Advisory Committee has created a new educational poster highlighting invasive species that pose the greatest threat to Virginia's resources. The poster highlights six species already in the state, and six on its fringes.
The six already in the state include three fast-spreading trees and plants: tree of heaven, phragmites and Japanese stilt grass. The three animals already present are the voracious northern snakehead fish, shellfish-eating rapa whelk and fire ant, which destroys crops and attacks people and wildlife.
The six threats include the zebra mussel, emerald ash borer, sirex wasp, rusty crayfish, Chinese mitten crab and sudden oak death.
You can get a copy of Virginia’s poster of pests for $5 to cover shipping and handling costs. Order them from the Friends of the Rivers of Virginia, PO Box 1750, Roanoke, VA 24008.
For details about invasive species in Virginia, visit vainvasivespecies.org.
The Smithsonian Environmental Research Center, located in Edgewater, Md., is specifically on the lookout for one of Virginia’s most wanted, the Chinese mitten crab, named for its furry looking claws. Anyone who sees one is asked to report the sighting to the center. The center is documenting the distribution and abundance of the crabs to provide information for plans to control their spread and limit their damage.
Since 2005, more than 100 of the crabs, which are native to East Asia, have been found in mid-Atlantic estuaries from the Chesapeake Bay to the Hudson River, and may have the potential to spread south to Florida and the Gulf of Mexico. Biologists worry their increasing population could threaten other populations and may damage banks and levees because they burrow into the ground.
The key identifying characteristics of Chinese mitten crabs are their furry claws. All adults and juveniles more than an inch long have furry, white-tipped claws that are equal in size. The crabs have light brown to olive green round bodies, or carapaces, that can be 3–4 inches wide in adults. The carapace is smooth and has four lateral spines; the fourth spine may be small. Between the eyes is a U-shaped notch. Unlike the common blue crab, mitten crabs have four, sharp-tipped walking legs and no swimming legs.
People who catch a mitten crab are asked to freeze it. They are asked to report sightings, along with details including date, specific location, size and a close-up photograph or, if possible, the actual specimen to SERC.
Reports can be made and photos uploaded by visiting a new reporting website and going to the tab "My Crabs."
Authorities have equally fatal ends in mind for snakeheads. The Maryland Department of Natural Resources, the Potomac River Fisheries Commission, and the U.S. Fish and Wildlife Service meanwhile, have asked fishermen to kill all the snakeheads they catch.
"We do not want snakeheads in our waters," said Don Cosden, inland fisheries director for the Maryland DNR. "This initiative is a way to remind anglers that it is important to catch and kill this destructive species of fish."
Biologists believe the fish, a predator native to Asia which has invaded the Potomac River, could affect the ecosystem and impact populations of other recreationally and commercially important species. They hope the initiative will slow the fish’s population growth and reduce its abundance.
From now until the end of the year, anyone who catches a northern snakehead with a hook-and-line and posts the catch, including a photo of the dead fish, on the DNR's Angler's Log will be entered into a year-end drawing for prizes that include a $200 rod and tackle package, a Maryland State Park Passport and a 2012 Potomac River fishing license.
Anglers are asked to report the location of their snakehead catches as specifically as possible, and include a ruler or other measuring device in the photo to indicate the size of the fish. If the snakehead has a tag inserted in its back, anglers should call 1-800-448-8322 and report the tag number to receive a special edition hat and a certificate from the U.S. Fish and Wildlife Service.
Meanwhile, Pennsylvania is working against other invaders; the emerald ash borer; Didymo, the algae which can cover stream bottoms; and the zebra mussel, which have entered the Susquehanna river system and reached the top of the Chesapeake Bay.
The emerald ash borer, which kills the commercially valuable ash tree by tunneling under the bark, was first detected in Pennsylvania in the summer of 2007. It has also been reported in Maryland; Virginia; Washington, D.C.; and West Virginia.
People are the main way the destructive pest is moved from place to place, primarily by moving firewood or other wood products.
To minimize the spread of the pests, the Pennsylvania Department of Agriculture has implemented a quarantine banning the importation of out-of-state firewood. People who suspect they have seen emerald ash borer should call the department's toll-free pest hotline at 1-866-253-7189.
Didymo and zebra mussels also are moved by people. They attach easily to boats and fishing gear and Pennsylvania has launched education campaigns to inform fishermen and recreational boaters how they can help stop the species’ spread.
Zebra mussels entered the Great Lakes in the 1980s in ballast water in ships. Since then, they have spread rapidly. Though individually small – about the size of a thumbnail—they are incredibly effective filter feeders and form dense colonies. The colonies reduce the plankton available to native animals and the oxygen content of the water bodies they infest, leading to very clear waters with very few native species.
Didymo carpets stream beds with a brown mass, like wet cotton or wadded toilet paper, that chokes off most other stream life.
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