Texas Game and Fish, Volume 13, Number 4, April 1955 Page: 26
32 p. : col. ill.View a full description of this periodical.
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Minnow Propagation * Continued from page 9
that all of the sodium arsenite
should be applied to the water be-
cause if it is sprayed on marginal
vegetation that cattle can get to and
eat, the cattle will be poisoned.
Some species of minnows can be
seined from a pond successfully but
during warm weather golden shin-
ers that are seined will be killed or
will shortly die. If golden shiners
are dipped out or trapped, however,
they will be found to be a very
hardy minnow that will live excel-
lently in a holding trough, summer
or winter.
DISEASES
This is a subject that alone re-
quires a large size bulletin. Fortu-
nately such a bulletin has been writ-
ten and printed. I: is Care and
Disease of Trout, by H. S. Davis,
Research Report No 12, for sale by
the Superintendent of Documents,
Washington, D. C. for a price of 35
cents. This bulletin, while primarily
Perfectly tuned by hunter who has called
thousands of fox, wolves, and cats. Why
tune and guess-tune again-then guess
again? WEEMS CALLS stay in tune be-
cause reed is locked in place.
Call is 4" x I" black walnut
Change of locked reed at any time for 25c.
Instruction record, 10" 78 rpm $2
SSUIRREL CALL, easiest to operate,
guaranteed to call squirrels......$1
At Your Dealer or Direct Postpaid
WEEMS WILD CALL
P. O. Box 7261 Fart Worth 11, Texasaimed at discussions and treatments
of diseases of trout, is also most ap-
propriate for diseases of minnows.
Three of the most common dis-
eases encountered are fin rot, fun-
gus and "Ich." Fin rot is caused by
bacterial infection that is charac-
terized by a progressive disintegra-
tion of the dorsal and/or tail fin.
The disease can be detected by a
white line that moves from the
outer margins to the bases of the
fins, destroying the tissue between
the fin rays as it progresses. The
best control of fin rot is accom-
plished by dipping minnows for one
or two minutes in a 1 to 2,000 solu-
tion of copper sulphate (6.5 ounces
of copper sulphate dissolved to 100
gallons of water). The minnows
that are already badly infected
should be destroyed because the dip
will not cure them and it will pre-
vent the other minnows not yet
showing signs of the disease from
becoming infected.
Fungus, Saprolegnia, a water
mold, is readily discernible due to
the fact that it presents a white
hairy appearance. This organism
usually occurs as a secondary infec-
tion following a primary attack on
the fish by bacteria, flukes or proto-
zoans. If scales should be knocked
off by seining or the protective fish
slime removed by handling it will
permit spores of the organisms to
attack the fish. In two of our hatch-
eries we have recently found that
the spores attack fertile eggs of the
black bass causing the death of the
embryos. The control for fungus
calls for dipping infected fish in
either a 3 per cent salt solution
until they show signs of distress or
else dip the minnows for ten seconds
in a 1 to 15,000 solution of mal-
achite green (1/8 ounce in 15 gal-
lons of water).
"Ich," Ichthyophthirius multifilis,
is a protozoan. Fish infected with
this parasite look like they have
been sprinkled with salt. Since it is
hard to kill the encysted stage of
these protozoans a suggested treat-
ment is to hold the minnows in
troughs that have a good current of
water flowing through. The young
parasites will develop from the adultencysted in the epidermis of the fish
and leave the cyst looking for fish
that they in turn can use for their
reproduction cycle but the swift
water running through the trough
will wash them away. The minnows
should be kept in the trough of
running water for several days after
all the parasites on the fish have
disappeared.
The best control of disease, how-
ever, is one of prevention. Our
hatchery personnel makes a practice
of giving all the fish a dip in the
malachite green solution every time
the fish are handled. When new
fish are brought into the hatcheries
they are checked for parasites,
given a dip and quarantined for a
day or so in troughs to see if any
disease will develop. Another obser-
vation from our hatcheries reveals
that when our fish are well fed,
they are usually free of disease. This
is particularly true with the small
channel catfish's becoming infected
with "Ich."
Under Water Supply it was stated
that water introduced into the pond
should be devoid of any type of
fishes. One of several reasons for
that statement is the fact that when
fish are present in the water supply
source, they can become infected by
and incubate various types of par-
asites that can be carried by the
water into the minnow ponds. Such
cases have happened in several of
our hatcheries.
The menace of disease epidemics
is the reason that each pond must
have its own water intake and waste
outlet. The writer made a survey of
one minnow hatchery that consisted
of a series of twelve ponds in which
water was pumped into the first
pond that was provided with an
overflow pipe running into the sec-
ond pond and in like manner
through the whole series until it
was finally wasted from the last
pond. An outbreak of fin rot oc-
curred in the second pond and was
carried through the next ten ponds
in the pond series. Due to this epi-
demic, the owner lost over 750,000
marketable minnows. All minnows
were killed except those in the first
pond. With a different water sys-TEXAS GAME AND FISH
26
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Texas. Game and Fish Commission. Texas Game and Fish, Volume 13, Number 4, April 1955, periodical, April 1955; Austin, Texas. (https://texashistory.unt.edu/ark:/67531/metapth1588361/m1/28/: accessed July 16, 2024), University of North Texas Libraries, The Portal to Texas History, https://texashistory.unt.edu.; crediting UNT Libraries Government Documents Department.