Download Brook Trout Life Cycle and Habitat

Brook Trout
Life Cycle and Habitat
Directions:
1. As you watch this slide show, watch for vocabulary terms we learned
today. The first time they appear, you will see them in RED! (not redd!)
2. At the end of the show, you will find definitions of all 18 terms.
Check your definitions of these terms to make sure they are complete
and correct!
Terms:
ecosystem
population
habitat
dissolved oxygen
biotic
pH
redd
Fry
abiotic
spawn
species
parr mark
pool
organism
alevin
riffle
run
Brook Trout Life Cycle
Brook Trout (Salvelinus fontinalis)
RANGE
Brook Trout are native to eastern
Canada and much of the
northeastern United States. (See
map -- area with lines)
They have been introduced in other
parts of the continent where it is
considered an invasive species,
harmful to native fish. (See map -area colored in with black.)
Trout, especially brook trout, are very peculiar about their habitat, having certain physical
habitat requirements that must be met.
1) Steadily-flowing stream
Brook Trout Habitat
Requirements
2) Riffles, Runs, and Pools
3) High dissolved oxygen levels
4) Clear, Clean, Cool water
5) Bank Cover & Instream Debris
6) Gravel streambed
7) Prey species
Brookies prefer
the relatively
shallow, moving
water of a stream
to a lake.
This means it
should flow along
a slight slope, but
not too steep or it
will flow too fast!
The stream should meander (curve gently) so that it forms
riffles, runs, and pools.
(Cobbles =
small rocks
or stones)
Riffle
Pool Formation
This photo shows a deep
pool formed by a bend in
the stream.
These deep pools are an
essential part of the
habitat required by all
stream trout.
Healthy trout streams
have a series of shallow
riffles followed by deep
pools.
These pools provide trout
with a place to swim and
hide from predators.
Riffles and Dissolved Oxygen
Trout, and especially brook trout, require water that is highly oxygenated.
Riffles like this are well oxygenated because the surface of the water is broken so
that oxygen from the atmosphere is readily absorbed.
Cool Water
around 48°F is ideal
(Water at or above 70°F can be
harmful!)
Trees along the stream
help keep the water cool.
Spring-Fed Streams are usually cool.
CLEAR, CLEAN WATER
Brookies are less tolerant of cloudy water than are rainbow and brown trout.
Clear water allows
sunlight to penetrate to
the streambed,
promoting plant growth
which provides food for
the trout’s prey.
Clear water also makes
it easier for brook trout
to avoid predators,
including fishermen.
Bank Cover
Prevalent bank cover is a necessary element of every trout stream.
Trout use this cover to escape
predators (birds, fishermen, etc.)
and to find cooler water temperatures
in the areas shaded from the sun.
Without bank cover,
brook trout do not survive in
high numbers.
The removal of bank cover is a
frequent problem for streams in urban
or residential settings.
If cover is removed and more of the
stream is exposed to the sun, the water temperature will become warmer and less
suitable for brook trout.
In-stream Debris
Much like bank cover, instream debris like fallen
tree branches provide
trout with necessary
cover.
However, if there is an
excess of fallen trees, the
flow of the stream can
become impeded.
This can ultimately lead to
the formation of stagnant
pools with abundant algal
growths, which is NOT
good for brook trout..
Gravel bottom (streambed) (substrate)
Gravel or rocky stream substrates provide
ideal spawning grounds for brook trout.
Trout construct spawning beds or "redds"
in the gravel to deposit their eggs.
The females make the redds in the autumn.
After hatching, the young trout, or “fry" (first
they are called sac fry or alevin until they use up
their yolk sac; then they are called fry when they
start swimming) stay under the stones for some
time before venturing out into the open water.
It is important that sediment does not reach
the stream in large amounts that could potentially
cover the gravel streambed, which would reduce
spawning area and smother newly hatched trout fry.
A stream that meets all these requirements
will also provide an ideal habitat for the prey
species eaten by the brookie:
Insects and insect larvae, smaller fish,
crayfish, salamanders, etc.
Ecology Vocabulary Terms, part 1
Habitat
• environment that provides things an organism
needs to live, grow, & reproduce
• Organisms have different requirements for
survival, therefore they live in different habitats
Biotic (factor)
Abiotic (factor)
• Living (or recently living) parts of a habitat
E.g. grass, prairie dog, hawk, worms, fungi ,
dead leaves
(could also be something a living thing made,
like a bird’s nest or beaver dam)
• Nonliving parts of an organism’s habitat
e.g., water, sunlight, oxygen, temperature, soil
Ecosystem
Community
Population
Organism
Species
• The community of organisms that live in a
particular area, along with all the non-living
surroundings (aka both biotic and abiotic
factors).
• All the different populations that live
together in a particular area.
• All the members of one species that live in a
particular area.
• One individual living thing
• A group of organisms that are physically
similar and can mate with each other to
produce offspring that can also mate and
reproduce.
Dissolved oxygen
oxygen that is dissolved in water
most organisms, including trout,
require oxygen to carry out
their life processes.
pH
the measure of how acidic or
alkaline a solution is.
pH is measured on a scale of 0 – 14.
trout need a neutral pH (7).
riffle
a shallow area in the stream where it
runs over stones or rocks.
this adds oxygen to the water.
run
place in the stream where it is fairly
straight and has smooth, unbroken
flow.
pool
area of slow-moving, deep water
spawn
redd
to spawn is to release eggs in water.
brook trout spawn in fall.
the shallow depression in the gravel or on the
stream bottom made by female fish, such as the
brook trout, where she deposits her eggs.
alevin
newly hatched baby brook trout that still have the
yolk sac.
can’t swim; just lie on bottom and feed on their yolk sac
also called “sac fry”
fry
once a baby trout consumes its yolk sac and it able to
swim and feed on its own it is called a fry.
(both singular & plural!)
parr mark
vertical stripes developed by fry.
when it has the marks, it is often called a “parr.”
these marks eventually fade and are not as “stripey.”
CHALLENGE: See if you can make a chart that includes the abiotic and biotic factors of the brook
trout’s habitat mentioned in this slide show.
Brook Trout Habitat
biotic factors
abiotic factors