VHS on the radar; bass tests positive

Sturgeon Bay, Wis. – DNR Bureau of Fisheries Management Director
Mike Staggs is urging Green Bay, Lake Michigan, and Lake Winnebago
system anglers and boaters to follow preventive steps to avoid
spreading the sometimes-deadly fish virus VHS to other waters.

Staggs said one of three smallmouth bass submitted for testing
during the Sturgeon Bay Open Bass Tournament on May 17 came up
positive for viral hemorrhagic septicemia, or VHS. The bass were
sent in after anglers and DNR staff saw that a large number of live
fish brought in for weighing in the catch-and-release event had
open skin lesions.

The disease was confirmed in Door County bass two years earlier,
also on live fish.

While the DNR has not seen any large-scale fish kills from VHS
the past two years, Staggs said fisheries staff still don’t know
what the full impacts could be in the long term. The discovery does
show that VHS is active this year and underscores the need for
anglers and boaters to take steps to prevent its spread, Staggs
said.

“We don’t want this disease to spread,” Staggs said. “People
should definitely not get complacent. If they need extra
motivation, think about other exotic invaders that could be spread
(with carelessness) like zebra mussels or quagga mussels, or any
invasive species.”

Staggs said there was a limited fish kill on the Oconto River
earlier this month, and a bass sample was sent in for testing. DNR
staff have sampled fish elsewhere in the state, but Staggs said he
wasn’t aware of any other VHS-suspicious kills.

Anglers are encouraged to follow the rules and recommendations
set out and modified after VHS first was discovered in Wisconsin in
the Lake Winnebago and Lake Michigan systems two years ago. That
includes not moving live fish, draining water from boats and
equipment, buying bait locally, and following rules for using
leftover bait.

“It’s particularly important that anglers and tournaments that
target smallmouth bass in Green Bay diligently take the prevention
steps and consider additional measures, like disinfecting livewells
that were holding smallmouth bass,” Staggs said.

Meanwhile, the Michigan DNR is awaiting results from fish
sampled in early June from Lake St. Clair, where a few thousand
smallmouth bass and low numbers of other species were found
dead.

Preliminary results detected heavy Flavobacterium columnare
infection, or columnaris, a common fish bacterial pathogen that can
cause mortalities when fish are stressed after spawning, from
excess human handling or from other infections.

“It’s possible fish could test positive for both columnaris and
VHS,” Staggs said. “One or the other might not have killed it, but
with two, it would kind of put the coup de grace on it.”

So far, preliminary results from VHS tests on several waters
statewide have not found the disease, meaning VHS has not been
detected elsewhere in the state beyond the Lake Winnebago and Lake
Michigan systems.

VHS is not a human health threat but can kill 37 different
species of fish, including trout, muskies, bass, and bluegills, and
it caused large fish kills in some Great Lakes waters in 2005 and
2006. The disease first was detected in Wisconsin in 2007 in fish
from the Lake Winnebago and Lake Michigan systems.

Anglers inadvertently moving infected live bait is a main way
that VHS fish disease can spread; VHS also can be spread through
contaminated water.

For the latest VHS news, visit http://dnr.wi.gov/fish/vhs.

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