May 2011 OutdoorIllinois / 13
in wild fish in selected bodies of water
statewide. For the past four years, DNR
also has been testing for VHS in every
known susceptible species within the
Illinois hatchery system. To date, all
results have been negative for VHS.
In October of 2008, the Southern Illi-nois
University Carbondale Fisheries and
Aquaculture Center began conducting
intensive VHS surveillance in wild fish
throughout Illinois under a cooperative
agreement with the USDA Animal and
Plant Health Inspection Service Veteri-nary
Services. Since then, 12,500 suscep-tible
fish from watersheds throughout
Illinois have been sampled. In addition to
the statewide surveillance program, near-ly
6,000 fish also have been tested as part
of a targeted surveillance for VHS in wild
fish in the Chicago metropolitan area, for
a total of more than 18,000 fish tested
over the past three years.
Additionally, SIU performs VHS test-ing
for commercial aquaculturists and
reports all surveillance data to both DNR
and the USDA Veterinary Services. VHS
has been detected in a few fish samples
collected from Winthrop and Waukegan
harbors along the Illinois shoreline of
Lake Michigan, a known VHS-positive
body of water. However, all fish samples
collected to date from other Lake Michi-gan
harbors in the Chicago area, and
from all fish collected from Illinois lakes,
rivers and canals outside of Lake Michi-gan,
have tested negative for VHS.
Since Illinois is a potential corridor
between the Great Lakes and the Missis-sippi
River basin (via the waterways in
the Chicago metropolitan area), informa-tion
on fish movement from Lake Michi-gan
into the Chicago waterways is criti-cal
to assessing the risk of VHS spreading
into inland waters from Lake Michigan.
To aid in evaluating that risk, SIU has
undertaken a study funded by USDA to
determine rates of natural movement by
VHS-susceptible fish species from Lake
Michigan into the Chicago waterway sys-tem.
This information is being obtained
using two approaches.
In the first approach, larger fish col-lected
along the Illinois shoreline of
Lake Michigan are marked with color-coded,
printed tags bearing an individ-ual
identification number, and then
released. Subsequent sampling in the
spring of 2011 will monitor the location
of tagged fish. Anglers who capture
tagged fish are asked to contact SIU via
the phone number displayed on the tags
(see photo) to report the location
where the fish was caught.
The second approach to assessing
movement of VHS-susceptible fish
involves analysis of natural chemical “fin-gerprints”
in fish otoliths (earstones)
that record information about the envi-ronments
in which an individual fish has
lived. This technique is being used for
fish that are too small to carry an artifi-cial
tag. Using this technique, it is possi-ble
to determine whether a fish collect-ed
in the inland rivers and waterways in
the Chicago area is a lifetime resident of
those rivers and waterways, or is an
immigrant from Lake Michigan.
Awareness
DNR, the USDA and SIU are engaged
in a number of efforts to increase aware-ness
of VHS, and compliance with pre-vention
measures to control the spread
of this disease and aquatic invasive
species. These activities include:
Developing a model biosecurity plan
for Illinois aquafarms (see the Aquacul-ture
Biosecurity Manual at http://fishda
ta.siu.edu/secure/bioman.pdf);
Coordinating a biosecurity workshop
for aquaculturists;
Distributing 20,000 synthetic
chamois-style towels imprinted with
prevention strategies, hotline numbers
and Web sites to recreational boaters
and commercial fishermen throughout
Illinois;
Installing 200 informational signs at
high-traffic boat launches in Illinois.
The goal of the first two strategies is
to reduce VHS-related risk to wild fish
populations and the economic viability
of Illinois aquaculture. The goal of the
latter two strategies is to remind boaters
and fishers of what is at risk and what
they can do to protect aquatic resources
while they are on the water.
Additionally, SIU is gathering data on
the relative risk of VHS-transfer posed
by individuals involved in recreational
activities in Illinois waters. SIU surveyed
recreational boaters and fishers through-out
Illinois to determine their current
understanding and awareness of con-trolling
and containing VHS and aquatic,
invasive species. These studies have
provided important information about
typical boating practices; how, where,
why and to what extent recreationists
use their boats; and their past and future
engagement in conservation behaviors.
The study found that boating prac-tices
in Illinois may be contributing to
the spread of aquatic invasive species
and fish diseases in the region. While, on
average, respondents reported almost
always draining water from their boats
and bait buckets, they only sometimes
engaged in other seemingly “low effort”
practices, such as removing aquatic
plants and animals from boats or con-ducting
visual inspections of their boats.
Higher-effort activities, such as rinsing
boats with high pressure water or flush-ing
motor cooling systems, were the
least-practiced actions.
A critical finding of these studies is
that boaters lack knowledge about aquat-ic,
invasive species and fish diseases and
are unfamiliar with the threat they pose
to ecosystems, recreation and
economies. However, it also was noted
that, given the knowledge that the
waters they boat on are infested with
aquatic invasive species and diseases
such as VHS, the likelihood that respon-dents
will engage in these preventative
practices in the future increases dramati-cally.
These results are encouraging, and
indicate that the cooperative education
and outreach efforts are having a positive
impact on the public and their willing-ness
to protect Illinois aquatic resources
from VHS and aquatic invasive species.
How the Disease is Spread
The most likely means of spreading
aquatic invasive species and pathogens
such as VHS from Lake Michigan into
other water bodies in Illinois is through:
• Moving infected fish from one
body of water to another—e.g., live
game fish caught in an infected body of
water or live baitfish caught or used in
an infected body of water and transport-ed
to another location.
• Moving infected water from
one body of water to another—e.g.,
discharging infected water and fish from
ships, live wells on fishing boats, and
bilge water from recreational and fish-ing
boats.
• Stocking or releasing infected
fish or water from infected fish
hatcheries.
• The natural movement of infected
fish from one body of water to anoth-er,
such as that which occurs through
flooding or normal fish movement.
Prevention
Recreational boaters and fishermen
can help avoid the spread of VHS and
aquatic invasive species by following
these guidelines:
• Do not move fish or plants
between bodies of water. Dispose of
unwanted baitfish and fish parts in the
trash.
• Do not move any water between
bodies of water. Drain water from
boat, motor, bilge, live wells and bait
containers before leaving the water
access.
• Spray, dry boat trailer and recre-ational
equipment—especially after
leaving known VHS-infected waters.
Power wash boat hulls and gear with hot
water (preferably 140 degrees Fahren-heit)
or rinse and then dry the boat and
gear completely for 12 hours.
• Do not introduce fish of
unknown health status into popula-tions
of farmed fish.
Teresa L. Dudis, DVM, is a Veterinary
Medical Officer at USDA APHIS Veteri-nary
Services Illinois and can be reached
at (217) 494-5189.
Do Your Part
The public can assist by reporting
information about a fish kill to the
DNR Aquaculture and Aquatic Nui-sance
Species Program at (217) 785-
8772. If you observe a fish kill, record
the body of water, species of fish and
the number of dead or dying fish.
Do not collect samples of dead or
dying fish.
See Administrative Rule 875 at
www.dnr.state.il.us/legal/adopted/875.
pdf for more information regarding
VHS regulation.
More information on VHS may be
found at www.focusonfishhealth.org
and www.protectyourwaters.net.
12 / OutdoorIllinois May 2011
As part of a study on fish move-ments,
anglers are asked to report
catch locations of fish bearing an
SIU color-coded tag.
VHS awareness activities include
installation of informational signs at
high-traffic boat launches in Illinois.
All fish collected from
Illinois waters to date have tested
negative for VHS.
(Photo courtesy Greg Whitledge, SIU-C.)
