June 2022 - 22

" Viruses can shut a hatchery down and
change the landscape, so they are given high
priority, " said Carl Smith, program manager
for the department's Fish Health Laboratory.
Fortunately, the most common pathogen
found in Wyoming is a bacteria, not a virus.
Bacterial coldwater disease occurs naturally
in the water sources for many hatcheries.
Transmission can occur through the water
column and through the eggs of infected adult
salmonids.
" This is the number one disease we combat
at Speas, " Alsager said. " If we see fish mortality,
we send fish to the lab for testing. They culture
the bacteria, diagnose and prescribe medicated
feed for treatment. "
Some pathogens can persist despite a
Each year the Wyoming Game and Fish Department's Fish Health Laboratory in Laramie tests fish from each of Wyoming's fish
hatcheries to ensure they are free of pathogens. Lab personnel test the fish for viruses, bacteria and parasites. In this photo a
pipette is used to transfer a homogenized fish sample into a tube for viral testing. Once deemed free of pathogens, a hatchery
receives a certification report from the lab and is free to stock fish around the state. (Photo by Robin Kepple/WGFD)
PREVENTING
THE THREATS
After two years of the COVID-19
pandemic most of us are familiar with the
ease and rate at which a disease can spread in
a population. Fish have their own diseases to
contend with and fish in hatcheries are not
immune to them. This is why Game and
Fish requires each of its hatcheries to have
an annual fish health certification.
Certification is obtained by passing a
veterinary inspection from the department's
Fish Health Laboratory. Each year, lab
personnel collect fish from each hatchery for
pathogen testing. A pathogen is an organism
that causes disease and can include viruses,
bacteria and parasites. Chapter 10 of the
Wyoming Game and Fish Regulations
requires annual testing for three bacteria,
three viral pathogens and one parasitic
pathogen at each hatchery. Pathogens vary
in their significance, survivability, ease of
spread and how they are controlled.
22 | June 2022
hatchery's best effort. A microscopic parasite
called Myxobolus cerebrali causes whirling
disease in fish and was discovered at Ten Sleep
Hatchery during routine testing in 2008. The
parasite infects young trout by burrowing
into the cartilage in the skull. This affects the
nervous system and equilibrium, causing an
infected fish to swim in circles.
As a result Ten Sleep Hatchery was
completely remodeled in 2011. New concrete
vaults were built around the hatchery's three
springs to contain the water and exclude
surface water. Large drum filters equipped
with ultraviolet lights were installed to rid the
water of pathogens, and other equipment was
installed to condition the water for optimal
fish health.
Whirling disease also was found in the
incoming water at Story Hatchery in 2005,
which resulted in the hatchery ceasing its
fish stocking program. Whirling disease is
not transmitted from parents to offspring so
Story Hatchery can still serve as a broodstock
facility to provide fish eggs to the rest of the
state. As an extra precaution, eggs are treated
with iodine before shipping.
When Wyoming trades trout to other
states for warm-water fish such as catfish,
there is potential for the spread of pathogens
and aquatic invasive species. Therefore, any
hatcheries Wyoming trades with must be
certified both as disease and aquatic invasive
species free. To provide an additional layer of
protection fish managers perform a screening
process on these fish to make sure no unwanted
organisms are included in the shipment.

June 2022

Table of Contents for the Digital Edition of June 2022