BROOK TROUT FRY STOCKING GUIDE
VERMONT FISH & WILDLIFE CONSERVATION GROUP
Brook trout are Vermont’s only native stream-dwelling trout. Actually a
member of the char family, brook trout thrive in cold, clean waters, and
help serve as indicators of the health of the watersheds they inhabit.
Brook trout do not compete well with introduced fish, particularly perch,
bass, and rainbow and brown trout. This inability to compete, combined
with their requirement of cold, clean water, has relegated most wild
brook trout populations to headwater streams and a few medium-sized
rivers. Lacustrine (Lake/Pond) populations are even more limited.
Where should I stock brook trout fry? How many fry should I stock?
The best use of brook trout fry is in unpopulated, newly The recommended stocking density for brook trout fry
formed beaver ponds. Stream brook trout populations is roughly 200-500 fish per acre. The average beaver
in Vermont usually have adequate natural reproduction pond is less than one acre, so we recommend one bag
to maintain their populations. Brook trout young-of- of fish (about 300-500 fry) per pond. No pond,
year estimates of 500-2000/mile from electrofishing regardless of size, should receive more than two bags of
surveys are common and stocking fry on top of these fish. Stocking more fish will only increase competition
wild trout populations is not recommended. In cases and result in stunted growth. Keep in mind, the most
where brook trout populations are not supported, it is productive lakes in the state have fish densities of
usually habitat limitations such as high water about 30 pounds per acre. This works out to about 80
temperatures or lack of cover that are limiting the eight inch trout.
population, not reproduction.
Will the fish I stock survive?
There are already fish present… should I still Many factors affect the survival of brook trout fry, but
stock? the most important is oxygen. If a pond does not have
No. Brook trout do not compete well with other fish adequate flow throughout the year, or becomes too
species, and should not be stocked in waters where warm (remember August dry times), it will likely not
other species are present. You should also use caution support brook trout. It only takes a few minutes
when stocking fry in waters where brook trout are without enough oxygen to kill the fish. Some predation
already present, especially if you think they may be wild (larger fish, herons, mink, etc.) is expected, but as long
(i.e. not from previous hatchery stocking). Adult brook as there is enough cover in the pond, some fish will
trout as small as 6” will readily eat newly stocked fry, survive.
thereby greatly reducing the chance of survival. Wild
brook trout are always preferable to hatchery fish, and
stocking can actually be detrimental to wild
populations. For more on the benefits of wild trout,
check out the other side of this sheet.
FRY STOCKING INSTRUCTIONS
Active beaver ponds are the only recommended stocking location. Inactive ponds
generally do not remain full for very long since the dam is no longer being maintained.
Only stock ponds that beaver are actively using
look for fresh cut trees around the pond and winter food under the ice
the top of an active beaver lodge does not freeze over in the winter
Once you have selected a good pond, temper the bag of fish
allow enough time for the bag water temperature to equal the pond water
temperature (5 to 15 minutes)
Watch for thin ice!
also watch for two layers of ice, as fish will go between layers
Try to release fish near the deepest water (usually the streambed),
or where water enters the pond
Remember, a bag of fish is more than enough for most beaver ponds, and usually enough
for a series of ponds.
WILD TROUT VS HATCHERY TROUT
Research has shown a great deal of genetic diversity among wild brook trout populations. Brook trout living in adjacent
watersheds can be very different genetically, as they have evolved to deal with the specific environmental conditions found
in each watershed. This diversity allows brook trout to adapt to changing environmental conditions. Strategically, wild
trout do not have “all their eggs in one basket".
Many stocked trout are less genetically diverse than wild trout. Most broodstock trout are descended from relatively few
parent fish, meaning they contain only a small subset of the genetic material found in the wild. In addition, fisheries
management policies have lead to specific behavioral characteristics being preserved, which may have further narrowed
down the genetic diversity of these fish. This lack of diversity makes hatchery trout less able to adapt to environmental
changes and more susceptible to diseases.
Hatchery trout differ both genetically and, equally as important, phenotypically. That is, hatchery trout behave, look, breed
and feed differently. For example, hatchery trout are less wary of predators and are more likely to feed during the day.
Hatchery trout have a greater propensity to take prey at the surface (and are therefore more easily caught by anglers) and
appear to be less successful at breeding.
It is important to remember that if brook trout are not present in a stream or pond, it is almost always because of poor
water quality or the presence of competing fish species. No amount of stocking can remedy these problems. Habitat
improvement, such as planting trees along stream banks, is the best way to establish new brook trout populations.
The prevalence of fish diseases such as whirling disease and viral hemorrhagic septicemia (VHS) require even more scrutiny
of the use of cultured fish. These diseases are spread by moving fish from one waterbody to another, including through
VERMONT FISH & WILDLIFE CONSERVATION GROUP
PO Box 207 East Charleston, VT 05833 www.vtfwcg.org