May 21, 2007 (ITHACA, N.Y.) -- A lethal fish virus in the Great Lakes and neighboring
waterways is approaching epidemic proportions, according to Paul
Bowser, Cornell professor of aquatic animal medicine in the College of
Veterinary Medicine. The viral hemorrhagic septicemia virus (VHSV),
which causes anemia and hemorrhaging in fish, has now been identified
in 19 species and poses a potential threat to New York's $1.2 billion
pretty obvious this is an epidemic even if it isn't official," said
Bowser. "There are just so many species affected and so many
Three new fish kills have occurred in 2007 in New York waters since the
virus was identified in the Great Lakes Basin in 2005. In the St.
Lawrence River, hundreds of thousands of round gobies have succumbed to
the disease; gizzard shad die-offs from VHSV in Lake Ontario west of
Rochester and in Dunkirk Harbor on Lake Erie also have been reported.
This month the Wisconsin Department of Natural Resources made a
presumptive identification of the virus for the first time in the Lake
Winnebago chain of inland lakes about 25 miles south of Green Bay on
Lake Michigan; confirmation is pending. And millions of dead freshwater
drum formed windrows of carcasses along the beaches of Lake Erie in
2006, all victims of VHSV.
Other species from the Great Lakes
Basin area that have tested positive by Cornell include bluegill, rock
bass, black crappie, pumpkinseed, smallmouth and largemouth bass,
muskellunge (New York's No. 2 sport fish), northern pike, walleye,
yellow perch, channel catfish, brown bullhead, white perch, white bass,
emerald shiner, bluntnose minnow, freshwater drum, round goby, gizzard
shad and burbot. Roughly 1,600 fish have been tested at Cornell since
May 2006. Bowser suspects the virus may have originated from an
infected marine fish off the Atlantic Coast and that the virus is still
relatively new to the region. Other possible sources of the virus
include the movement of infected fish by airborne or terrestrial
predators, anglers using infected bait minnows, contaminated fishing
equipment or live water wells in boats, boating activities and ballast
"Basically, we don't know how it got here, but it is here
and it's spreading," said Bowser. "It would be wonderful if we did
know. However, I don't think we ever will."
The Great Lakes VHSV
is not related to the European or Japanese genotypes and poses no
health threat to humans, said Bowser. However, as a general rule,
people should avoid eating any fish (or game) that appears abnormal or
behaves abnormally. Not all infected fish, however, exhibit symptoms.
Some may be carriers, and visible signs of the disease may vary from
species to species.
Containing the spread of the virus in New
York will require restrictions on the movement of live fish, testing
fish and surveillance. For instance, New York state regulations require
that bait fish be used in the same body of water from which they were
collected unless they have been tested. In Wisconsin, new emergency
rules prohibit anglers and boaters from moving live fish and require
them to drain their boats and live wells before leaving Wisconsin's
Great Lakes waters, the Mississippi River and those tributaries up to
the first impassable dams, according to the Associated Press.
spread of the virus could have a devastating impact on aquaculture and
particularly the channel catfish trade, which constitutes about 80
percent of aquaculture business in the United States, said Bowser.
Catfish is a very popular food fish in the Deep South.
detected VHSV in channel catfish in our surveillance efforts," said
Bowser. "The ability of the virus to go beyond a carrier state and
cause disease in this important aquaculture species is a major research
question we plan to investigate this year."
Source : Cornell University News Service