What's In a Name?
Brook trout: named for the habitat in which it is found
Salvelinus (sal-veh-lynn´-uss) taken from a word
meaning "little salmon"
fontinalis (fon-ten-al´-iss) means "living in springs"
Where Do They Live?
Brook trout are native to headwaters and small streams of northeastern
and southeastern Minnesota but have been introduced to many parts
of the state. Their preferred habitat includes headwater spring ponds
and small spring-fed streams that have cool, clear waters with sand
and gravel bottoms and moderate amounts of vegetation. They also congregate
behind beaver dams. Brook trout often share this habitat with mottled
sculpins, white suckers, creek chubs, brook sticklebacks, and pearl
How Big Do They Get?
How Long Do They Live?
How big a brook trout gets is dependent on what stream it comes from.
The common size that many anglers catch from heavily fished streams
or lakes is 150 to 250 mm (6 to 10 in), but in areas of little fishing,
they can get as large as 400 mm (15 in). Those that live along the
shores of Lake Superior reach 600 mm (24 in). The state angling record
is 3 kg (6 lbs. 5oz). This fish was caught from the Pigeon River in
Cook County. The world record is 6.6 kg (14.5 lbs).
In Minnesota streams, brook trout commonly live for 3-4 years. A few
make it to the age of 5 or 6 years.
What Do They Eat?
The food of the young brook trout is mostly small insects. Older fish
eat larger invertebrates including many types of aquatic (water) insects,
sideswimmers, snails, and worms. They also feed on minnows and other
What Eats Them?
Brook trout have few aquatic predators because few piscivorous ("fish-eating")
fish live where they do. Larger trout, especially brown trout, eat
smaller brook trout. They are more likely to be eaten by such fish-eating
birds as herons, and kingfishers. Otters and snapping turtles also
prey upon them.
How Do They Reproduce?
Many brook trout females and some males reach sexual maturity in their
first year of life. Unlike Pacific coast salmon, brook trout do not
die after spawning. They spawn each year of their adult life. In Minnesota,
the spawning season for the brook trout is normally in the autumn
months, roughly October and November. Sometimes spawning in streams
flowing into Lake Superior begins in late September. During these
spawning times the water temperatures are usually 4.5- 9.5° C
In streams, brook trout move to riffles where spring water passes
through the gravel. Here the female constructs a nest by swimming
hard into the gravel and vibrating her body and sweeping her tail.
She repeats this action many times over a period of a day or two.
A male may defend this area while the female builds the nest. After
the nest is ready, the female lies in it and is briefly courted by
the male. Eventually, the male lies along side of the female and arches
his body over hers. The two vibrate and release their eggs and sperm
at the same time. The female then uses her tail to cover the eggs
with gravel. Flow from the spring seeps into the gravel keeps the
eggs oxygenated and clear of silt. The eggs hatch after 50-150 days
depending on water temperatures. The colder the water temperature
is the longer the development period.
Conservation and Management
Brook trout are managed as a cold-water sport fish species.
Natural History of Minnesota Fishes
Photographs by Konrad P. Schmidt and Donald Biemborn
Text by Nicole Paulson & Jay T. Hatch in cooperation with
the Minnesota Department of Natural Resources' MinnAqua Aquatic Program