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August 23, 2011

Rules helping contain disease, keep other invasives out

MADISON - VHS fish disease has not spread to new waters in 2011, a result state fisheries and invasive species officials credit to anglers and others following rules to prevent spreading the virus.

And they say those rules also will help protect against other aquatic invasive species and diseases, including the Asian carp recently caught in the Lower Wisconsin River and DNA detected in water samples in the St. Croix River.

VHS, or viral hemorrhagic septicemia, does not affect people nor pets, but can infect several dozen species of fish and cause them to bleed to death.

DNR collected fish from 19 waterbodies throughout Wisconsin between April 12 and June 1 as part of its surveillance efforts to detect VHS. Tissue samples from 2,773 fish were submitted to three laboratories for the tests, which take a month. None of the fish were positive for VHS, according to Eric Eikenberry, a DNR microbiologist/fish biologist who coordinated the sampling.

Also, fish sampled from three lakes that supply DNR hatcheries with water were negative for VHS, as were DNR hatchery-raised fish tested before they were stocked or moved to other facilities.

While VHS was found in 2011 in waters where it's been found in the past and remains a serious threat, "we're pleased it hasn't spread to new waters," says Mike Staggs, DNR's fisheries director.

"We appreciate the efforts that anglers and boaters have made to keep Wisconsin's fish healthy and we think it's absolutely helping contain VHS and will help prevent the spread of other aquatic invasive diseases and species."

That includes two other aquatic invasive species recently in the headlines, Asian carp and spiny water fleas. DNR announced last week that a bighead carp had been caught in the Lower Wisconsin River and the Minnesota DNR announced that silver carp DNA -- the fish known for its jumping behavior -- had been detected in the St. Croix River. Bighead and silver carp eat plankton and can potentially decrease populations of native fish that rely on plankton for food, including all larval fishes, some adult fishes, and native mussels, says Bob Wakeman, who coordinates DNR efforts to prevent and control aquatic invasive species.

For example, VHS rules that prohibit the harvest of bait from waters known or suspected to have the fish virus will help keep Asian carp out of Wisconsin waters. Without the ban, bait harvesters might accidentally catch a young Asian carp, which looks similar to gizzard shad and many minnows, and take it to another lake or river where it might escape, says Bob Wakeman, who coordinates DNR's efforts to prevent and control aquatic invasive species.

And rules to drain water from boats, live wells, fishing equipment and containers before leaving a boat landing will help keep spiny water fleas from being moved elsewhere. These microscopic aquatic animals compete for the same food as small native fish and have been documented in three Wisconsin lakes so far. Lake Mendota, the site of the most recent discovery, was in the news recently when lake experts predicted worsening problems with toxic blue-green algae as the fleas decimate populations of a zooplankton that helped keep the algae in check.

"These are potentially serious threats to our lakes and rivers and fishing," says Wakeman. "All of the preventative steps will help, and they're all needed. If you just do one thing, you're missing the boat. All of these steps together can help protect our lakes and rivers and keep our fishing healthy."

More information on rules to prevent the spread of aquatic invasive species and VHS can be found on the DNR website.

FOR MORE INFORMATION ON VHS TESTING CONTACT: VHS testing Eric Eikenberry (608) 264-9257;


Last Revised: Tuesday, August 23, 2011

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