Nebraska Trout in the Classroom Curriculum
Acknowledgements....................................................................................................................................... 1
Introduction .................................................................................................................................................. 2
Activity Template .......................................................................................................................................... 3
Life Cycle: Predict a Hatching Date .............................................................................................................. 4
Life Cycle: Life Cycle Log............................................................................................................................... 8
Life Cycle: Tale of a Scale ........................................................................................................................... 15
Life Cycle: only the strong survive ............................................................................................................. 20
Water Quality: Healthy Water, Healthy Fish.............................................................................................. 22
Water Quality: When It’s Hot! ................................................................................................................... 28
Water Quality: What’s in the Water? ........................................................................................................ 34
Water Quality: Nutrient Soup .................................................................................................................... 41
Water Quality: Sum of the Parts ................................................................................................................ 47
Water Quality: Additional Activities........................................................................................................... 51
Food Webs: Aquatic Web of Life................................................................................................................ 52
Food Webs: Water bug Hunt ..................................................................................................................... 56
Food Webs: Additional Activity .................................................................................................................. 59
Fish Anatomy: What makes a Fish – Trout Dissection ............................................................................... 60
Fish Anatomy: Fashion a Fish ..................................................................................................................... 74
Fish Anatomy: Gyotaku .............................................................................................................................. 80
Fish Anatomy: Protective Coloration ......................................................................................................... 82
Nebraska Fish Species: Fish Finder ............................................................................................................ 85
Nebraska Fish Species: Additional Activity .............................................................................................. 109
Summary and Review: Fish Bowl Trivia ................................................................................................... 110
Let’s Go Fishing! ........................................................................................................................................ 112
Nebraska Trout in the Classroom Order Form .......................................................................................... 118
1
Acknowledgements
The Trout in the Classroom Teachers Manual published by the Idaho Department of Fish and
Game Aquatic Education Program provided the format and much of the content for this
curriculum. Special thanks to Brenda Beckley, Idaho Trout in the Classroom Coordinator, for
her input and assistance with the Nebraska Trout in the Classroom curriculum.
Activities were also adapted from Aquatic WILD, Salmon in the Classroom, Minnaqua, and
Project WET and are noted within the curriculum.
Funding Sources:

The U.S Fish and Wildlife Service Sport Fish Restoration Program.

The Nebraska Game and Parks Commisison, Fisheries Division supplies all trout, trout
eggs, and trout feed to support the program. Special thanks to the Production Section for their
assistance.

Additionally, Trout Unlimited, Nebraska Chapter #710 has provided the funds to equip
two classrooms in the Nebraska Trout in the Classroom pilot program.
2
Nebraska Trout
By Daryl Bauer, Nebraska Game and Parks Commission Fisheries Biologist
Nebraska has a great diversity of geography, climate, flora and fauna. Anglers in the state have the
opportunity to fish for a variety of warm-water, cool-water and cold-water species including trout.
Although historical records are “sketchy”, it is possible that cutthroat trout were native to at least a few
streams now found within the state of Nebraska. Cutthroat trout can still be found in a handful of
Nebraska waters as well as rainbow, brown, and brook trout. Although the rainbow, brown and brook
trout now found in the state are not native, there are some Nebraska streams where wild, naturallyreproducing, populations of those trout exist. Rainbow trout are also stocked extensively throughout
the state both in waters that can support trout year-around and in waters where those fish are stocked
for put-and-take fishing.
Most of the waters that provide cold-water habitat capable of supporting trout throughout the year are
found in northern and western parts of Nebraska. Since they are cold-water fish, trout need habitats
that offer both cool and well-oxygenated water at all times, especially during the heat of summer. Most
of those cold-water habitats are spring-fed streams in the Niobrara, White, Hat, Loup, Dismal, and North
Platte river basins. In addition cool-water releases from Lake McConaughy support a tail-water trout
fishery in Lake Ogallala and in the canal and North Platte River for a few miles downstream.
With their need for high quality and cool water, there are only a limited number of Nebraska streams
that can support trout. Due to their scarcity, all of our Nebraska trout waters are very important
habitats. Groundwater levels and spring flows are critical to those habitats and groundwater irrigation
development has already doomed trout fisheries in some of Nebraska’s trout streams and threatens
others. In addition bank erosion and sedimentation from land development and agriculture are
additional threats to Nebraska stream trout fisheries.
One of the highest priorities for fisheries management on Nebraska’s trout streams would be the
protection of stream flows. Given adequate water, Nebraska fishery managers in conjunction with help
from Nebraska trout anglers continue to enhance habitat in trout streams by protecting banks and
placing in-stream structures that provide deeper water, overhead cover, and stabilize channels.
Stocking of trout is another important tool in the management of Nebraska’s trout fisheries. Trout eggs
are procured from neighboring western states, and then hatched in Nebraska state fish hatcheries. One
important stocking strategy is the introductory or supplemental stocking of trout fingerlings into
streams capable of supporting those fish. On other waters catchable-size, approximately 10-inch, trout
are stocked to provide immediate fishing opportunities. Put-and-take trout stockings in heavily-fished
urban and parks waters across the state have become an important recruitment tool for beginning and
youth anglers by providing relatively easy fishing during fall through spring. Although most of the urban
and parks waters where catchable-size trout are stocked are not trout habitats, they can support those
fish while water temperatures are cool. Most, if not all, of the put-and-take trout stocked in those
urban and parks waters are caught and harvested before they perish the following summer when water
temperatures rise.
In spite of their scarcity, and because of it, trout are important to Nebraska anglers. The state’s anglers
will continue to have the opportunity to pursue a variety of fish in a variety of waters, and that includes
trout. Whether in spring-fed streams and rivers, or urban waters, there are some beautiful brookies,
wily browns, acrobatic rainbows, and native cutthroats out there waiting to be caught!
3
Activity Template
Standards: A list of Nebraska’s
content standards that are
partially or completely met by the
activity.
Duration: The approximate time
needed to complete the activity.
CONTENT (some or all of these sections will be included
with each activity, as applicable):
Background: Relevant information about activity
concepts or teaching strategies.
Preparation: Work necessary to be done prior to the
activity, to prepare materials.
Materials: A list of materials
needed to complete the activity.
Some materials may be
requested from the Youth Fishing
Program.
Objectives: The qualities of skills
students should possess after
participating in the activity.
Warm up: Prepares everyone for the activity and
introduces concepts to be addressed. Provides the
instructor with pre-assessment strategies.
Activity: Provides step-by-step directions to address
concepts. Note: some activities are organized into
“parts”. This divides extensive activities into logical
segments. All or some of the parts may be used,
depending on the objectives of instruction.
Wrap up: Brings closure to the lesson and includes questions and activities to assess student
learning.
Extension: Provides optional additional activities for continued investigation into concepts
addressed in the activity.
Related reading: Optional reading with concepts similar to those covered in the activity,
used to enhance a student’s understanding.
4
Life Cycle: Predict a Hatching Date
Background: One of the first things your class
Standards:
Duration: 30 – 45 minutes.
Materials: Aquarium Thermometer,
Hatchery Information log, Student
Hatch Worksheet (pg. 6)
Objectives: Predict a hatch date for
your newly arrived eggs.
should do is predict a hatch date for your eggs.
Because egg development is dependent upon
temperature, by taking daily temperature records
you can monitor egg development to predict an
approximate hatching date. Trout egg development
is measured in temperature units. One temperature
unit (TU) represents every 1°F above 32°F in a 24
hour period. For example, if you plan on keeping
your tank at 52°F, the following math can be done to
calculate TUs:
Average temperature in a 24-hour period is 52°F.
50°F – 32°F = 18 TUs for that 24-hour period.
Over a period of one week: 7 days x 18 TUs = 126 TUs accumulated per week
Below is an approximate guideline for rainbow trout development rates. Variations can, and
probably will, occur. A general rule of thumb is that the colder the water, the more TUs are
required to reach the various stages of development. Conversely, the warmer the water, the
faster the rate of development. Remember, fish do not rely on mathematics to hatch!
APPROXIMATE DEVELOPMENT RATES
Temperature Units (TU)
To Eyed Egg Stage
To Hatch
To Fry Stage
305-315
600-625
750-775
NOTE: Your predicted hatch date may indicate a scheduling conflict with your hatch time and
school vacation. Hatch times can be manipulated somewhat by adjusting water temperature to
better fit your timeline. Any temperature changes must be gradual however, and remember to
avoid temperature extremes. Contact your TIC coordinator if you have any concerns.
Preparation: For at least one week prior to egg arrival, keep a daily record of water
temperature in your aquarium. Average your records to find the temperature at which your
trout will incubate. Your eggs will come with a log indicating the date the eggs were fertilized
and the average temperature the eggs were kept at before you received them. If this
5
information is missing, contact your TIC coordinator prior to completing this activity. Prepare
copies of the Student Hatch Worksheet for each student.
Warm up: Review the Hatchery Trout Life Cycle worksheet. Share the history of your trout
eggs with the classrooms: The eggs come one of five hatcheries in Nebraska. At the hatchery,
adult female trout who are ready to reproduce are handled by hatchery staff. Gentle pressure
on the trout’s belly releases her eggs into a collection pan. Eggs are fertilized by hatchery
workers using milt collected from male trout that is stirred in with the eggs. The fertilized eggs
are then placed in water; they absorb the water and become hard and round. The eggs are
allowed to develop in special cold water incubators at the hatchery until the eyes of the
developing fish are visible through the shell of the egg. At this time, the eggs are delivered to
the classroom.
Activity: On the following page is a worksheet for predicting the hatch date. Complete this
worksheet as a group activity.
Wrap up: Post your predicted hatch date on your aquarium. Ask students to think about why
the actual hatch date may be different than your predictions. What variables in the classroom
environment might influence hatch?
6
HATCH WORKSHEET
Name
When Will They Hatch?
Rainbow trout need to have 625 Temperature Units (TU) to hatch.
Daily Temperature Units (TU) = Water Temperature – 32 degrees
Hatchery Data
Our fish will hatch in
Date eggs were fertilized:
days!
Date eggs arrived in class:
The predicted hatch date is:
Total days eggs were at hatchery:
Hatchery water temperature:
Month
Hatchery Calculations
Daily temperature units (TU) from hatchery:
Total TU from hatchery:
Day
– 32 =
TU x
days =
TU –
TU =
TU
TU
Classroom Data
Total TU needed to hatch:
Total TU from hatchery:
Classroom aquarium temperature:
Classroom Calculations
TU still needed to hatch:
Daily TU in classroom aquarium:
Days left until hatch:
– 32 =
TU
÷
TU
TU
TU =
TU
7
HATCHERY TROUT LIFE CYCLE
Courtesy of Idaho Trout in the Classroom Curriculum
8
Life Cycle: Life Cycle Log
Standards:
Duration: 30-45 minutes initially, 510 minutes daily
Materials: Blank, unlined
notebooks; colored pencils or
paints; glue and scissors; Life Cycle
worksheet (pg. 13).
Objectives: Students will describe
the life cycle of a trout, observe
daily changes in the appearance and
behavior of their trout, explain the
life cycle stages of their trout,
reflect on the process of raising
trout.
Background:
Recording the growth and physical
changes of the trout with pictures and notes is a great
first-handed way for students to study the life cycle. A
field journal or log is the perfect place to record all of
these changes. A journal is much more than a diary and is
essential to any scientist’s fieldwork. Entries in a field
journal draw heavily on scientific information but are
often written in the first person and incorporate personal
observations, feelings, and questions. It is a tool for
recording what one sees, learns, and feels, and gives
students a way to develop and apply their own creative
talents.
As your class observes the trout, allow time for them
to record observations, thoughts and questions in
their logs. Some will sketch simple pencil drawings
while others will paint colorful, detailed images. Try
working with pens, pencils or watercolors to capture
an image. Some people record their observations in
charts, list and labels, while others will write long, detailed descriptions.
Reviewing the life cycle of trout will be essential to understanding the changes the trout are
going through as you observe them. The typical life of a trout begins when eggs are deposited
and fertilized in the gravel of a stream. Once fertilized, the eggs are covered by gravel which
protects them from direct sunlight, strong river currents, and potential predators. After seven
to ten days, the head and body regions of the fish begin to form. The eggs are very fragile at
this stage and any movement may prove fatal. About 60 to 90 days after fertilization, eyes
begin to appear. This “eyed” stage means that the embryo is developing normally and is now
able to withstand considerable movement. (This is the stage at which you received your eggs.)
As the fish continue to develop within their shells, it is believed that eventually the shells
becomes limiting – the embryos cannot extract enough oxygen from surrounding water. The
wiggling embryos then release enzymes to dissolve the egg shell, and eventually a trout breaks
through the shell. The alevins, or sac fry, emerge when they are between ¾” to 1” long. The
alevin discard their shell membranes, but the yolk-sacs remain attached to their stomachs.
Oxygen is now absorbed from water flowing over their gills.
Alevin will move up to the surface of the streambed but mostly remain hidden within the
gravel. They are completely dependent upon their yolk-sac’s store of protein, minerals, salts
9
and fats for nourishment. This fixed food supply must last for two to four months. If sediment
has not built up in the gravel and around the alevin (limiting its oxygen supply) their growth
rate will be determined by the temperature of the water. High water temperatures will make
the alevin develop faster. In warmer water, metabolic processes (digestion and respiration)
occur more quickly. During incubation, the eggs are subject to many hazards, such as disease,
drought and flooding; many eggs do not make it through this vulnerable period.
Once the yolk-sac has been absorbed, the incubation period finally ends. The trout, now called
fry, must leave the gravel in search of new food sources. At this point, the young fry are still
heavier than water and must reach the surface of the water to inflate their swim bladders (see
Anatomy: What Makes A Fish? Pg. 60). The fry tunnel out of the gravel and travel up through
the water. When a fry makes it to the surface of the water, it snatches air with a sideways,
snapping motion of its head. It then drops back, keeping its mouth and gill covers tightly closed
to swallow the air.
When young fish reach the size of a human finger, they are called fingerlings. Vertical marks
(parr marks) along their sides help hide them from predators. At this time, the trout may also
be called parr. The fish tend to live in gentle water near the stream bank. It is only when they
get bigger and stronger that they move to the faster current.
Trout reach full maturity after about two years. Adults eat insects as well as other fish, even
smaller trout. At this time, the trout tend to reside in the main current of the stream. The age at
which a trout reaches sexual maturity varies due to many different factors, such as genetics or
availability of food. Trout may spawn when as young as three, but most trout do not spawn
until they are six or seven. Trout are cued by changes in day length and temperatures to
reproduce. The fish swim upstream, spurred by the flow of the clear, cold snow melt, until they
find the spot where they hatched.
Males will fight for spawning rights to the female. The most dominant male will win and spawn.
The process of courtship and nest building will last for hours. Only when the female is ready will
the spawning commence. The female finds an area with adequate gravel and water flow and
creates a redd. A redd is a sort of ‘nest’ for the eggs. She fans her caudal (tail) fin to rearrange
and clean the gravel. Redds can be up to a foot deep to protect the eggs. The female will signify
to that male that she is ready to release her eggs by arching her back and quivering over the
redd. The male will join her, and they both release their eggs and sperm. An average female
rainbow trout will deposit roughly 2,000 eggs and will immediately begin to bury these eggs.
Trout can spawn more than once, unlike most salmonids, and may spawn every one to three
10
years. Once the adult dies, its body will decompose in the water to provide nutrients back to
the water and help the cycle of life continue.
Warm up: Review the life cycle of trout with the Wild Trout Life Cycle worksheet so that
students recognize the life cycle stages their trout are going through. Compare the life cycles of
wild trout and hatchery raised trout.
Launch the idea of journaling by introducing students to the Journals of the Lewis and Clark
Expedition. The combination of the journals’ scientific importance and their historical mark on
this area of the country makes them an ideal choice. Lewis’s entry on Thursday, June 13th, 1805
describes his first encounter with what are now known as Great Falls, MT and cutthroat trout.
The entry can be found at http:// lewisandclarkjournals.unl.edu/index.html. Present different
styles of journaling, from keeping daily records in charts, to writing detailed notes with
illustrations.
Activity:
1. Inform the class that they will be observing the growth of their trout as scientists would, by
recording daily logs concerning water conditions, the trout’s life cycle stage, the health of
the fish, their behavior, and any other observable characteristics.
2. Have students create their own journals. To do this, students use any bound book with
blank pages (un-ruled allows more creativity) or make their own journal covers and pages.
By allowing students to create a cover of their own design, they make a personal bond with
their log. Have them draw, paint or collage the cover. Let students develop their journals in
their own styles and use their own techniques to make journal entries.
3. Allow students 5 to 10 minutes daily to write in their journals. Below are questions to
prompt journaling:
Conditions: What is today’s date? What is the water temperature? What is the
temperature in the room? How much have you fed them? Is the water level low/high?
Do I see anything that surprises me?
Alevin: Describe the alevin. What color are they? Do they have fins? What is most
interesting about them? How well do alevin swim? What do alevin do when light shines
on them? How might this reaction help them to survive in the wild?
Fry: Observe how the fry move. How many fins are there? Draw the fish. Draw and label
the fins. Describe the motion of each fish. What is the direction and range of
movement? Do paired fins move together in the same way? Are some fins used more
than others? What happens to the fish’s fins when it is still?
11
Color: What colors can you identify on the fish? Is the back the same color as the
stomach? Why do you think the fish are colored this way? Which is easier to see, a fish
swimming near the top of the tank or near the gravel?
Senses: Do you think fish have good eyesight? Why? Can fish hear? How do you know?
Can you see the lateral line? What purpose does it serve?
Behavior: What do fish do when they are startled? Why? Do the fish move as a group?
What is this called? Are all the fish the same size? How do the fish interact with each
other? Do individual fish have established areas of the aquarium that they stay in? What
do fish do at feeding time? Do they all get the same amount of food?
Predictions: What are your predictions for your trout? Do you expect them all to
hatch/survive? What are your expectations for your hatchery or stream visit?
Wrap up: Have students complete a final entry with the release of your fish. Have your trout
developed as you expected? Have your feelings for trout changed after raising them? Do you
feel like you understand fish better? Complete the Wild Trout Life Cycle Puzzle.
Extension:
1. Have students write poems, haikus, or in other literary styles reflecting on the growth of
their trout. Allow them to use information they gathered in their logs to express
observations, emotions, and predictions.
2. Have the classroom create an online blog, discussing their daily experiences and challenges
with the trout. Connect with other classrooms across the country also participating in Trout
in the Classroom.
Related Reading:
Do Fishes Get Thirsty? Questions Answered by Dr. Les Kaufman
In the Swim by Douglas Florian
There Was an Old Lady Who Swallowed a Trout by Teri Sloat
Trout, Trout, Trout! (A Fish Chant) by April Pulley Sayre
12
WILD TROUT LIFE CYCLE
Courtesy of Idaho Trout in the Classroom Curriculum
13
TROUT LIFE CYCLE WORKSHEET
Name
Courtesy of Idaho Trout in the Classroom Curriculum
14
TROUT LIFE CYCLE WORKSHEET ANSWER KEY
Courtesy of Idaho Trout in the Classroom Curriculum
15
Life Cycle: Tale of a Scale
Standards:
Duration: 45 minutes
Materials: Copies of Crappie Scale
Impression Worksheet (pg. 18);
markers, colored pencils or crayons;
transparency of fish scale to lead
class
Background: In this activity, we will examine a
crappie’s scale. Crappie are native to Nebraska and are
found throughout the state in rivers and lakes. Crappie
grow fast and their scales are relatively easy to decipher
in relation to the very small scales of a rainbow trout.
There are four types of fish scales - placoid, cycloid,
ctenoid (pronounced ‘ten-oid’), and ganoid. Trout
and most bony fish have cycloid scales. Fish with
cycloid scales have the same number of scales their
entire lives - the scales enlarge to accommodate
growth (scales that are lost to injury will be
Objectives: Students will correlate
regrown). This results in a pattern of concentric
different seasons with a fish’s
growth rings on the scale, which look similar to the
growth.
growth rings in the trunk of a tree. The growth rings
on a scale are known by scientists as circuli (singular circulus).
Just like counting the rings of a tree, biologists can determine the age of a fish reading its scales
with a microscope. So, how do biologists do this? Actually, aging fish is fairly easy. The
development of circuli is similar to that of tree rings. During periods of rapid growth, the rings
are widely spaced and when growth slows, the rings are constricted together. Rings are formed
on a cycloid scale constantly, so biologists can read into seasons, rather than just years with
trees. In the great plains, fish will grow rapidly in the summer months when water
temperatures and food availability are highest; they experience slower growth during the
colder winter months. Therefore, the scales typically exhibit bands of widely spaced growth
rings (summer) separated by constrictions (winter). By counting the number of winters on a
scale, a biologist can determine how long that fish has been alive.
In addition to viewing a trout’s scales to age a fish, biologists can also collect and examine
otoliths. The otolith (which literally translates to “ear stone”) is a small bone that floats in a
fluid-filled capsule located near the base of a fish’s skull. They function in equilibrium
maintenance, but can be used to age fish and are generally considered more accurate than
scales (particularly for older specimens) and can even determine daily growth. However, the
fish must be dead before an otolith is removed. Scale removal is relatively harmless to the fish,
therefore scale reading is generally preferred.
Biologists commonly collect age data for fish species in a water body to determine the relative
health of the population. Age is compared to other information such as the length and weight
16
of the fish, and will indicate whether a population is growing slowly in relation to other
populations. For example if the average age-3 crappie in Lake A is 6 inches, and the average
crappie in Lake B is 8 inches, biologists may be concerned about the population in Lake A. This
information is very useful for making decisions on how to manage a fishery to produce healthy,
quality fish.
The scale image is obtained by removing a scale from the fish and then making an impression of
the scale in a piece of acetate. The impression is then viewed under magnification.
Activity:
1. Start a discussion by asking the class if the fish in your aquarium will grow more scales as
they get bigger, or if they have all the scales right now that they will have for the rest of
their lives. Explain how trout have the same scales their whole lives and that the scales
have to grow with the fish.
2. Pass out copies of the scale drawing and coloring utensils. Have students observe the scale.
Does this remind them of anything else found in nature? A tree’s rings. If you have a picture
or tree cookie, use it to compare with the scale. Note that some of the irregularities on the
image are a result of making an imperfect impression of the scale into a piece of plastic.
3. Discuss tree rings and how they are formed. Each tree ring is a layer of wood cells produced
in one year. Does a tree grow the same amount every year? Are the rings all the same size?
Why not? Each year brings different weather and a different growing season. A drought one
year won’t allow the tree to grow much while a wet and warm year will promote
tremendous growth.
4. We can see the same is true with fish. The rings are not all the same size. Fish, however,
grow rings constantly (not just once a year). Knowing what we do about trees, what do you
think causes changes in the growth fish? Summer brings warm weather and lots of food for
growth. The opposite occurs in the winter.
5. Point out and label the core of the scale and explain that the first growth rings, or circuli,
are formed from this point.
6. Ask students to identify the mark of the first winter on the fish scale. Have them color in
the area of the first summer’s growth with a crayon.
17
7. Continue to identify each mark of winter, and fill in each season of growth with a different
color.
8. Ask how many summers this fish had been alive when it was collected?
Wrap up:
1. Ask the students how the scales of the trout they are raising would compare to the scale of
a wild trout. Do you think the hatchery trout would show the same markings on their scales
as wild fish? No, the aquarium fish are fed the same amount every day and the
temperature of their habitat doesn’t change, so their growth rings are perfectly even.
2. Ask the students why it might interest biologists to learn the ages of fish.
Extension: Once trout are showing their parr marks, view scales from your trout under a
microsope. You will likely need to sacrifice a trout to obtain the scales, because the fish are so
small and it will be difficult to remove scales without injuring a fish. You can also use a fish that
dies naturally. Scrape the skin lightly with the tip of a tweezer from tail towards head and place
scales with a drop of water on a slide. Cover with a slip cover to view. You may want to try this
prior to a classroom activity to determine how easy it is to see the scales with your classroom
scopes.
18
CRAPPIE SCALE IMPRESSION WORKSHEET
Name_____________________________________
19
CRAPPIE SCALE IMPRESSION KEY
Note that the constrictions identifying the winter seasons circle the entire scale, but the base of
the scale becomes very constricted and is difficult to get an impression of.
20
Life Cycle: only the strong survive
Standards:
Duration: 30 minutes
Materials: Copies of Survival
Worksheet (pg. 21)
Objectives: Students will estimate
survival of trout in natural habitat.
Background: The reproductive strategy of most
fishes is r- reproductive strategy, in which energy is
invested in a multitude of offspring that receive little
or no parental care. In terms of individual offspring,
very little energy is invested. Conversely, the Kreproductive strategy is typical of animals where
energy is invested in a few, large offspring that
require considerable parental care. In terms of
individual offspring, a great deal of energy is
invested.
On average, a female trout will lay 2,000 eggs during spawn. In nature, most of those offspring
will not survive to reproductive age. Few will survive to the next year, and less than one
percent may survive to adulthood.
Warm up: Fill a jar with a known number of beans or jelly beans and ask students to guess
how many beans are in the jar. Ask students to guess how many eggs a female trout can lay.
Ask students to picture what 2,000 looks like. Compare that number with your jar of beans.
Start a discussion about why trout lay so many eggs.
Activity: Complete the Survival Worksheet as a group activity. Students should write out the
equation for each step of the survival process.
Wrap up: Ask students to provide ideas of other things that could influence trout survival in
nature. Compare the likelihood of survival in nature to the likelihood of survival in your
aquarium. Ask students to describe things that could affect survival in the aquarium.
21
SURVIVAL WORKSHEET
Name:
Only the Strong Survive!
Use the details provided to find out how many rainbow trout typically survive from egg to
spawning adult. Show your calculations in the right column.
A rainbow trout deposits two thousand eggs
in a redd.
Two hundred eggs are not fertilized.
Twenty-eight eggs are washed out of the
gravel after an ATV driver crosses the stream.
A construction site upstream causes erosion.
The silt covers and kills four hundred ninety
alevins.
Two hundred four fry are preyed on by larger
fish, herons, bullfrogs and other predators.
Mowers clear vegetation along the stream
banks, causing insect populations to
decrease. Three hundred fifty-three trout die
because they can’t find enough food.
Mowers clear vegetation along the stream
banks, causing insect populations to
decrease. Three hundred fifty-three trout die
because they can’t find enough food.
Drought occurs the following summer. Water
levels drop and water temperature increases.
Four hundred twenty-five adult trout die
from disease.
Fisherman catch forty-seven trout.
How many trout survived?
22
Water Quality: Healthy Water, Healthy Fish
Standards:
Duration: 45 minutes initially, then
15 minutes weekly through the
duration of the trout rearing period.
Materials: Water testing kit
included with TIC tank set-up,
laminated water quality datasheet
(pg. 27), marker
Objectives: Students will learn how
to test water quality parameters in
their trout rearing aquarium and will
be introduced to how human
activities can affect water quality in
nature.
Background: Fish need oxygen, clean water and
nutrients to survive. To measure these requirements
in a lake, river or stream, biologists look at water
quality parameters such as temperature, dissolved
oxygen, pH and nitrates. Each of these parameters is
a limiting factor. If the level of each is too high or too
low, fish can be negatively affected. These factors
determine what kind of habitat a body of water can
support. Habitat is directly related to the different
species of fish that are found in a body of water.
Hatchery biologists can use these parameters to
decide what types of fish are stocked into different
bodies of water. In the trout rearing aquarium, these
water quality parameters must be regularly
monitored in order to keep the fish healthy.
Temperature
Different fish have different temperature
requirements. Trout are a cold water fish with an ideal temperature range of 50°F to 60°F,
whereas largemouth bass are warm water fish with an ideal temperature range of 70°F to 85°F.
Cold water holds more oxygen than warm water; additionally fish metabolism speeds up in
warm water and fish require more oxygen. Temperature can also affect ammonia
concentrations.
Dissolved Oxygen (will not be tested in the classroom)
Dissolved oxygen is defined as the amount of oxygen that will dissolve in water at a given
temperature. Trout are very active fish and consume a lot of oxygen from the water. In
streams, cool water flowing over rocks and boulders normally maintains high dissolved oxygen
levels. Lakes and ponds rely on plant photosynthesis for the addition of dissolved oxygen to
their waters. Oxygen concentration is inversely related to temperature. Cooler water holds
more oxygen. Conversely, warmer water holds less oxygen. As water temperature increases, a
fish’s metabolic rate increases and more oxygen is required. DO levels vary based on
temperature and the rate of decomposition occurring in a body of water. If DO levels are too
low, fish and other organisms will not be able to survive.
23
pH
pH (the power of Hydrogen) is a measure of water acidity or alkalinity. pH values range from 1
to 14. Along this scale, any number less than 7 is acidic. Any number greater than 7 is basic or
alkaline. Pure, pH balanced water has a pH of 7, which is neutral and ideal for most aquatic
animals. Any significant change in pH (dropping below 6 or rising above 8) is reason for concern.
Fish take oxygen from the water through their gills and give off carbon dioxide. When carbon
dioxide is expelled into water, a simple chemical reaction occurs producing a weak acid called
carbonic acid. Too many fish in a closed aquarium system can change the pH to dangerously
low pH levels. Acidic water (low pH) irritates gills, causes excess mucus production and
reduces the gills’ ability to exchange oxygen. Low pH also limits the fish’s ability to regulate its
blood salts, although adding calcium ions can reduce this effect. Some organisms are able to
survive in environments with a very high or very low pH. Most fish, however, prefer water with
a pH that is close to neutral. Immature stages of aquatic insects, such as mayfly nymphs and
stonefly nymphs as well as snails, tadpoles and crayfish are very sensitive to changes in pH and
prefer a range of 6-8. Many things can affect the pH of a body of water. For example, industrial
emissions from factories can cause acid rain. Acid rain lowers the pH of a body of water.
Different household items also have different levels of pH. For example, lemon juice is acidic
and has a low pH whereas ammonia is basic and has a high pH.
Turbidity (will not be tested in the classroom)
Turbidity refers to the clarity of water. The more solids that are suspended in water, the
cloudier the water is and the higher the turbidity. Some factors that contribute to turbidity are
rainstorms, pollution and bottom feeders (e.g., carp) that stir up sediment. If waters are too
turbid, photosynthesis can be slowed and there is an overall negative effect on fish health as
less nutrients are available in the food web. Turbid water also causes water temperature to
rise.
Ammonia
Fish continually release ammonia (NH3) through their gills, urine, and solid waste as food is
processed. Uneaten food and other decaying organic matter also add ammonia to the water. In
nature, ammonia (nitrogen) waste is usually not a problem. It is simply diluted into the stream
where the nitrogen is reabsorbed by aquatic plants and plankton. In a closed aquarium,
ammonia levels can build up very quickly, resulting in a fish kill. Ammonia (N3) is highly toxic to
fish. Even small amounts can be dangerous. High ammonia levels cause gill damage and
anemia. It can kill both eggs and fry. A biofilter breaks down ammonia. A balance between
ammonium ions and ammonia is controlled by pH and the temperature of the water. At higher
pH levels (>7) and temperatures, the toxic form increases its concentration.
24
Nitrites
Nitrogen is essential for many biological processes. In plants, it is essential for photosynthesis
and growth. Algae and other plants use nitrogen as a source of food. If algae have an unlimited
supply of nitrogen, their growth will continue unchecked and water quality can decline. Fish
need nitrogen to build protein. They are able to get nitrogen by eating plants or by eating other
protein (such as other fish or insects). Some forms of nitrogen can be harmful to fish when
there is too much in the water.
Nitrites are a normal product of the nitrogen cycle. As ammonia from metabolic wastes of the
fish and organic matter (uneaten food, dead plants, etc.) builds up, beneficial bacteria
transforms the ammonia to nitrite. Normally, nitrite is further transformed to nitrate. Nitrites
are highly toxic to fish, though once they are transformed to nitrates they no longer pose a
danger to the fish. If the beneficial bacteria becomes overwhelmed by the amount of nitrite
present, nitrite can quickly reach toxic levels. High nitrite levels cause ‘brown blood disease’
which makes the fish’s blood unable to carry oxygen. The lack of oxygen in the blood causes it
to turn brown. Fish can literally suffocate even though there is ample oxygen present in the
water.
Preparation: Double check the water quality test kit to make sure all supplies are stocked
and testing vials are clean. Do a trial test of all steps. Determine if standard or high range test
should be used (refer to equipment and care manual). Divide the class into groups of two or
three. You may find it helpful to pre-assign groups to cover a different test each week. Post
datasheet and Master Test Kit chart (included with kit) near the aquarium.
Warm up: Discuss the importance of testing each of the water quality parameters, and what
affects each parameter both in the classroom and in nature.
Activity:
Step 1. pH Testing
Standard
1. Fill a clean test tube with 5 ml of water to be tested (to the line on the tube)
2. Add three drops of pH Test Solution, holding dropper bottle upside down in a completely
vertical position to assure uniformity of drops.
3. Cap the test tube and invert tube several times to mix solution. Do not hold finger over
open end of tube, as this may affect the test results.
4. Determine the pH reading by matching the color of the solution against those on the pH
Color Chart. The tube should be viewed against the white area beside the color chart. Color
comparisons are best made in a well-lit area. The closest match indicates the pH of the
water sample.
25
5. Rinse the test tube with clean water after each use.
6. Record the results on the datasheet.
High Range
1. Fill a clean test tube with 5 ml of water to be tested (to the line on the tube).
2. Add 5 drops of High-Range Test Solution, holding dropper bottle upside down in a
completely vertical position to assure uniformity of drops.
3.-6. As listed above.
Step 2. Ammonia Testing
1. Fill a clean test tube with 5 ml of water to be tested (to the line on the tube).
2. Add 8 drops from Ammonia Test Solution Bottle #1, holding the dropper bottle upside down
in a completely vertical position to assure uniformity of 7 drops added to the water sample.
3. Add 8 drops from Ammonia Test Solution Bottle #2, holding the dropper bottle upside down
in a completely vertical position to assure uniformity of drops added to the water sample.
4. Cap the test tube and shake vigorously for 5 seconds. Do not hold finger over the open end
of the tube, as this may affect the test results.
5. Wait 5 minutes for the color to develop. Read the test results by matching the test solution
against the Ammonia Color Chart. The tube should be viewed against the white area beside
the color chart. Color comparisons are best made in a well-lit area. The closest match
indicates the ppm (mg/L) of ammonia in the water sample.
6. Rinse the test tube with clean water after each use.
7. Record the results on the datasheet.
Step 3. Nitrite Testing
1. Fill a clean test tube with 5 ml of water to be tested (to the line on the tube)
2. Add five drops of Nitrite Test Solution, holding dropper bottle upside down in a completely
vertical position to assure uniformity of drops.
3. Cap the test tube and invert tube several times to mix solution. Do not hold finger over
open end of tube, as this may affect the test results.
4. Determine the pH reading by matching the color of the solution against those on the pH
Color Chart. The tube should be viewed against the white area beside the color chart. Color
comparisons are best made in a well-lit area. The closest match indicates the pH of the
water sample.
5. Rinse the test tube with clean water after each use.
6. Record the results on the datasheet.
Step 4. Temperature
Record the temperature of both the aquarium water and the chiller on the datasheet.
Step 5. Notes
Record any changes in fish behavior or in water quality since last tests. Keep a record of any
dead fish removed from tank.
26
Wrap up: Ask students to discuss why fisheries biologists might be interested in testing these
parameters in local streams and reservoirs. Test results can indicate pollutants entering the
water. Water quality parameters determine the type of habitat available to fish, and can help
biologists to make decisions about the species that should be stocked in a specific place. For
example, largemouth bass rely on clear water to be able to search for prey. They would not do
well in a very turbid environment.
Extension: Take a field visit to a nearby creek and compare test results with your records
from the aquarium. Turbidity and Dissolved Oxygen test kits are available from the Aksarben
Aquarium for this exercise. (Water quality will also be tested at the stocking site when trout are
released.)
Related Reading: My Healthy Stream a publication of Trout Unlimited, available through the
Aquatic Education Program at Nebraska Game and Parks Commission.
27
WATER QUALITY DATASHEET
Date
Temp (°F)
pH
Ammonia
Nitrite
Notes
28
Water Quality: When It’s Hot!
Standards:
Duration: Part I – 45 minutes, Part
II – 30 minutes
Materials: Copies of Tolerance
Limit and Dissolved Oxygen
worksheets (pgs. 30, 32), graphing
paper
Objectives: Students will organize
data found in charts by creating bar
and line graphs, compare fish
species found in Nebraska,
recognize the relationship between
dissolved oxygen and temperature,
relate the graphs to infer
relationships
Background: Some fish can live in warm water
while other fish require colder water. By
experimenting with different kinds of fish and raising
water temperature a little bit at a time, biologists
have learned a lot about how fish respond to changes
in temperature in their environment.
One way to measure the temperatures a fish can
tolerate or live through is called the thermal tolerance
limit median (TLm). To measure this, fish are exposed
to warmer and warmer water temperatures. At a
certain point the water will become so warm that one
half (or 50%) of the fish will not tolerate the
temperature and will die. If that temperature was at
84°F, we can say the TLm is 84°F for that species. The
first table in this exercise lists the TLm’s for a number
of species found in Nebraska. The table also notes
whether the species is native or has been introduced
to Nebraska.
The second table compares dissolved oxygen levels in water to the water temperature. The
dissolved oxygen level is important to fish because it is a measurement of the amount of
oxygen mixed in with the water and available for fish to breathe. It should not be confused with
the oxygen atom found within one molecule of water (H2O). The line graph created in this
exercise will show that dissolved oxygen levels are directly related to water temperature. As
water temperature increases, the dissolved oxygen level decreases.
Activity (Part I):
1. Ask the class if fish can live at any temperature. Do all fish like the same temperature? It
should be evident that trout are particular about the temperature of their water. If the tank
got very warm, your trout would begin to die. Explain that when biologists are studying
certain fish, and their habitat, it is important to know what temperatures that fish can
tolerate.
2. Pass out graph paper and copies of the Tolerance Limit Worksheet.
3. Read the instructions together. Ask students what it means to be native to an area. What do
they think it means if a fish is native? Native fish are fish that occur naturally in a given
29
area. Introduced fish, conversely, are fish that are native to a different area and are
brought to Nebraska. Fish are often introduced to new areas because of their popularity as
game fish. In Nebraska, trout are primarily an introduced fish.
4. Have students work (independently or in groups) to graph and complete questions on the
worksheet. Remind students to create graphs with the proper labeling of axes and units. It
may be helpful to work together as a class to answer questions.
Wrap up (Part I):
1. Ask the class why this information is important to biologists.
 It allows biologists to predict the effects of a stream warming on certain fish species.
2. Ask students to think of what would cause a stream to increase in temperature.
 Cutting down the trees around a stream reduces the shade and warms the water.
 Using water to cool power plants introduces hot water back into a stream.
 Rain runoff that is heated up
Activity (Part II):
1. Have students get out their graphs from Part One and review the graph. Make sure
everyone understands the information and how to graph it. Next, ask why the students
think fish start to die in hot water. Discuss their ideas.
2. Pass out copies of the Dissolved Oxygen Worksheet.
3. Read the directions together. Review what dissolved oxygen is and why it is important.
4. Have students work (independently or in groups) to graph and complete questions on the
Dissolved Oxygen worksheet. Remind students to create graphs with the proper labeling of
axes and units. It may be helpful to work together as a class to answer questions.
Wrap up (Part II): Review the connection between dissolved oxygen and temperature.
30
TEMPERATURE TOLERANCE LIMIT WORKSHEET
Fish Species
Name
TLm (°F)
Native or Introduced
Bluegill
98
Native
Brook trout
72
Introduced
Brown bullhead
85
Native
Carp
95
Introduced
Channel catfish
95
Native
Crappie
87
Native
Creek chub
81
Native
Northern pike
82
Native
Rainbow trout
74
Introduced
Walleye
84
Native
Instructions
The table lists a variety of Nebraska fish species, their thermal limits, and whether they are native or
introduced to Idaho. Using graph paper, create a bar graph showing the 12-hr TLm for each species in the
table. Label the x-axis as the temperature and list the fish species along the y-axis. List the fish with the lowest
TLm at the bottom all the way up to the fish with the highest TLm at the top of the y-axis. Following each
species’ name put an (i) or (n) to designate if the fish is introduced or native. Use this information to answer
the questions that follow.
Questions
1. Which four species would be most likely to disappear if water temperatures increased?
2. Which four species would be the most likely to survive hotter water temperatures?
3. Which would most likely have lower water temperature: a small, shallow pond or a flowing spring-fed
stream? Why?
4. Carp and trout are both introduced species in Nebraska. Based on temperature tolerances, which do
you think is more likely to be found throughout the state?
31
TEMPERATURE TOLERANCE LIMIT ANSWER KEY
Fish Species
TLm (°F)
Native or Introduced
Bluegill
98
Native
Brook trout
72
Introduced
Brown bullhead
85
Native
Carp
95
Introduced
Channel catfish
95
Native
Crappie
87
Native
Creek chub
81
Native
Northern pike
82
Native
Rainbow trout
74
Introduced
Walleye
84
Native
Questions
1. Which four species would be most likely to disappear if water temperatures increased?
Brook trout, Rainbow trout, Creek chub, Northern Pike
2. Which four species would be the most likely to survive hotter water temperatures?
Bluegill, Channel catfish, Carp, Crappie
3. Which would most likely have lower water temperature: a small, shallow pond or a flowing spring-fed
stream? Why?
The answer to this question was not specifically addressed in the activity; however, by using
reasoning skills, most students should be able to come up with the correct answer. The “why” may
be more difficult to answer. A stream would most likely have the lower water temperature. Small,
shallow ponds are easily warmed by the sun’s energy and typically have very small inputs of cool
water. Streams, on the other hand, receive a constant supply of cold water from groundwater. They
are also constantly moving so they are not as easily warmed by the sun.
4. Carp and trout are both introduced species in Nebraska. Based on temperature tolerances, which do
you think is more likely to be found throughout the state?
Most of Nebraska’s streams, rivers and lakes are warm water systems. Few spring fed streams are
located in the Sandhills and panhandle region. Carp are very abundant in almost all types of water
body in Nebraska, and can be very invasive and damaging in some systems. They are well suited to
the temperature ranges of Nebraska’s waters. Trout, on the other hand, are stocked by NGPC in
selected water bodies statewide, but because they are warm water systems, trout cannot survive
and reproduce in them and are stocked with the intent that they be caught by anglers and removed
before water becomes seasonally too warm for their survival.
32
DISSOLVED OXYGEN WORKSHEET
Name
Water Temperature (°F)
Dissolved Oxygen (mg/L)
50
8.8
55
8.2
60
7.7
65
7.3
70
6.9
75
6.5
80
6.2
85
5.8
90
5.5
95
5.2
100
4.9
105
4.6
Instructions
Create a line graph using this information comparing dissolved oxygen levels to water temperature. Dissolved
oxygen (DO) is the amount of oxygen mixed in with the water. Fish need DO in order to breathe. Label the xaxis as the temperature and the y-axis as dissolved oxygen.
Questions
1. What does your line graph tell you about the relationship between DO and temperature?
2.
If we know the ideal water temperature for trout is 50 – 70°F, what DO range matches this temperature
range?
3.
Find the thermal limit for rainbow trout. What would the DO be at this temperature?
4.
Many things besides temperature determine how much dissolved oxygen is in water. What else might
affect how much oxygen is available to fish?
33
DISSOLVED OXYGEN ANSWER KEY
Water Temperature (°F)
Dissolved Oxygen (mg/L)
50
8.8
55
8.2
60
7.7
65
7.3
70
6.9
75
6.5
80
6.2
85
5.8
90
5.5
95
5.2
100
4.9
105
4.6
Instructions
Create a line graph using this information comparing dissolved oxygen levels to water temperature. Dissolved
oxygen (DO) is the amount of oxygen mixed in with the water. Fish need DO in order to breathe. Label the xaxis as the temperature and the y-axis as dissolved oxygen.
Questions
1. What does your line graph tell you about the relationship between DO and temperature?
As temperature increases, the amount of oxygen available decreases.
2.
If we know the ideal water temperature for trout is 50 – 70°F, what DO range matches this temperature
range?
6.9 to 8.8 mg/L
3.
Find the thermal limit for rainbow trout. What would the DO be at this temperature?
About 6.5 mg/L
4.
Many things besides temperature determine how much dissolved oxygen is in water. What else might
affect how much oxygen is available to fish?
Winds blowing across the surface of water can add oxygen, plants growing in the water create oxygen,
stream water rushing over rocks adds oxygen, decomposing plant and animal materials in the water
reduces oxygen, murky (or turbid) water can reduce oxygen by blocking sunlight that algae and plants
need to create oxygen through photosynthesis.
34
Water Quality: What’s in the Water?
Adapted from Project WILD Aquatic Activity Guide copyright by the Council for Environmental
Education. For more information about Project WILD contact Nebraska’s Project WILD
Coordinator at [email protected].
Standards:
Duration: 30-45 minutes
Materials: 8 colors of construction
paper, 3 sheets of each color;
Pollutant Worksheet (pg. 40);
Pollutant Information Handouts
(pgs. 38-39); scissors; small scoop to
measure out tokens; glue
Objectives: Students will identify
major sources of aquatic pollution
and make inferences about the
potential effects of aquatic
pollutants on wildlife and habitat.
Background: Water bodies such as rivers, streams,
ponds and lakes are important to humans and wildlife
alike. Water in our rivers and lakes is used for
drinking water, crop irrigation, transportation,
recreation, and habitat for many wildlife species.
Unfortunately, many of our nation’s water bodies are
not suitable for some of these uses due to pollution.
Pollutants enter waterways from either point or nonpoint sources. Point sources are clearly defined,
localized inputs such as pipes, industrial plants, sewer
systems, and oil spills. Federal and state
governments monitor and regulate point sources.
Non-point sources are harder to detect and control;
therefore they are often the major sources of water
quality problems.
Non point sources are indistinct inputs that do not
have a clearly defined source, such as runoff of oil and gas from roads or pesticides from
farmlands. Non-point source pollution occurs when rain, snow or irrigation moves over land or
through the ground, picking up pollutants and depositing them into surface water or
groundwater. Agriculture, forestry, grazing, septic systems, boating, urban runoff,
construction, changes to stream channels, and habitat degradation are all sources of non-point
pollution.
The most common non-point source pollutants are sediment and nutrients. These pollutants
enter water from agricultural land, feeding operations, construction sites, and other areas of
disturbance. Other common pollutants are pesticides, herbicides, pathogens, oil, toxic
chemicals, and heavy metals. A growing concern is also the potential toxic effects of chemical
compounds from medications that enter the water supply through wastewater.
Unsafe drinking water, fish kills, destroyed habitat, beach and lake closures, and many other
environmental and human health problems can result for these pollutants.
35
Pollution can be categorized into the following types:
 Chemical pollution: the introduction of toxic substances into an ecosystem (example:
pesticides from lawns or medications from wastewater)
 Thermal pollution: changing temperatures above or below the normal condition
(example: water heated by a power plant outflow)
 Organic pollution: oversupplying an ecosystem with nutrients (example: fertilizer runoff
from crops or lawns)
 Ecological pollution: stresses created by natural processes that add substances or
change the concentrations of naturally occurring substances in a system.
Chemical, thermal and organic pollution can also take place without human intervention.
When this happens it is called ecological pollution (examples: acid rain from volcanic eruption,
avalanches, shifts in oceanic currents).
State and federal governments protect water quality by regulating, monitoring, and enforcing
clean water programs. Examples of federal water pollution control are the Clean Water Act
(1977, amended 1987) and the Safe Drinking Water Act (1974, amended 1996). Public and
private businesses are using more pollution prevention and pollution reduction initiatives to
control water pollution, and more citizens practice water conservation in their homes and
communities.
Preparation: Cut construction paper into ½ square tokens – make 100 tokens of each of the
8 colors for a total of 800 tokens, saving one full sheet of each color to make a color key. Put
tokens into a box and stir so that colors are thoroughly mixed. Make copies of Pollutant
Information and Pollutant Worksheet handouts for each student.
Warm up:
1. List the four major categories of pollution (chemical, thermal, organic, and ecological) on
the blackboard and discuss each.
2. Pass out the Pollutant handouts and review each pollutant. Discuss how some pollutants
can fit into more than one of the four major categories. Assign each of the pollutants a
color and create a color key for the classroom that identifies the name, number and color of
each pollutant on the Pollutant Information Handout. Make sure that each student
understands each kind of pollution is represented in the activity by one color of token.
36
3. Divide students into research teams of three. Give each team a Pollutant Worksheet and
explain that each team will explore the pollution content of an imaginary trout stream.
Each team will be researching a different stream. Pass the box of tokens to each team and
have them measure out their share of tokens.
Activity:
1. Separate tokens into color coded piles, and identify each kind of pollutant using the Color
Key.
2. Glue the pollutant tokens into the appropriate column of the Pollutant Worksheet to create
a bar graph. Make sure that each team affixes the tokens to the sheet in the same order (as
indicated by the number code on the bottom of the sheet).
3. When students have completed their bar graphs, have the research teams compare their
results. Start a discussion about why each stream has different levels and kinds of pollution.
4. Tell students that quantities above two units of each type of pollution are damaging to
wildlife habitat in the stream. Ask each team to discuss how the pollutants in their streams
might affect your trout if you were to release them into that stream.
Wrap up: Ask students to match the pollutants with the four categories of pollution listed at
the beginning of the activity. Remember that some of the examples will fit into more than one
category. Ask students how the pollutants discussed in this lesson might affect the water
quality parameters they monitor in the trout rearing aquarium.
Extension:
1. List five things you can do to reduce the number of pollutants that you add to the
environment.
2. Study a local stream or river, either through a field trip or by using Google Maps, and
discuss what kinds of pollution may be affecting it.
Background:
The EPA launched a website and mobile application to help users find information on the
condition of thousands of lakes, rivers, and streams across the United States. Visit
www.epa.gov/mywaterway to look up a local stream or reservoir.
37
My Healthy Stream a publication of Trout Unlimited, available through the Aquatic Education
Program at Nebraska Game and Parks Commission.
38
POLLUTANT INFORMATION HANDOUT
Sediments
Small bits of earth made of soil, sand, clay and minerals wash from the land into the water.
Large amounts of these natural materials can pollute the water. Construction projects like new
housing developments or new shopping malls can make a lot of sediment pollution! Logging
operations can also make a lot of sediment when trees are cleared off the land, and crop land
that is not protected from the wind can cause sediment to move into the water. When a lot of
sediment gets into streams and lakes, it can fill in the streams so that there is not much space
left for water and make lakes very shallow. Sediment in water can also suffocate fish eggs that
are located at the bottom of streams. Sediment can also make the water look muddy so that
sunlight cannot get through to underwater plants that need it to grow.
Petroleum Products
Oil, gas, and kerosene finds its way into the water from boats and ships, deep sea oil-drilling, oil
refineries, gas stations, and even automobiles that leak oil and gas onto streets. Petroleum
products can harm or kill all kinds of aquatic life (fish, birds, plankton and underwater plants).
Human and Animal Waste
Human waste that is not treated at a waste treatment facility before it is released into water
contains harmful bacteria and viruses. Many diseases like cholera, dysentery, and typhoid fever
can come from water that is infected with waste. Waste can get into water from broken sewers
that deliver it from homes and businesses to treatment plants or from barnyards or stockyards
that flood, or even from yards where pet waste is not removed! Waste can also add too many
nutrients to the water, which can cause too much algae to grow.
Organic Waste
Many factories like food processing factories or paper mills release other wastes into water that
are a result of manufacturing a product. Often microscopic bacteria will eat those waste
products, but too much waste released into water will cause the bacteria populations to
increase and use up all the oxygen in the water. Fish and other aquatic animals that take
oxygen from water will die if all the oxygen is used up by bacteria that eat the organic waste.
39
Chemicals
Chemicals come from mining, factories, oil fields, and agriculture. Many of these are poisonous
to animals and plants living in the water. Chemicals can also change the pH levels of water, and
make it more acidic than fish and other aquatic animals can tolerate.
Detergents and Fertilizers
Many of these are poisonous to fish and harmful to humans. Fertilizers get into water from
runoff of rainwater from yards and agricultural fields. The fertilizers have nutrients like
nitrogen and phosphorous that can cause large amounts of algae to grow. Algae can cover the
surface of the water and block sunlight from getting into the water. Once the algae dies, it
becomes organic waste and bacteria will eat it and use up all the oxygen.
Heated Water
Hot water cannot hold as much oxygen as cold water. Electric power plants release hot water
into lakes and rivers, and this can reduce the amount of oxygen that is available to the animals
that live in the water.
Pesticides, Herbicides and Fungicides
Some chemicals are designed to kill a pest. These chemicals find their way into water after they
are applied to yards and agricultural fields and then runoff of rainwater or irrigation washes
them into the streams. They can also move through the soils and get into underground water
supplies. Like other chemicals, these can be poisonous to animals living in the water and can
change the pH of the water.
40
POLLUTANT WORKSHEET
1
2
Name:__________________________________________
3
4
5
6
7
8
41
Water Quality: Nutrient Soup
Adapted from the MinnAqua Fishing: Get in the Habitat! Leaders Guide copyright by the
Minnesota Department of Natural Resources.
Standards:
Duration: 30 minutes, plus daily
observations for up to 2 weeks.
Materials: Glass containers (clean
used jelly or baby food jars work
great) or plastic cups, plastic wrap,
water from a local pond or stream,
aquatic vegetation (can be found in
local waters or purchased at a pet
store), household plant fertilizer
(such as Miracle Gro), examples of
household items that contain
phosphorus and nitrogen (can use
photos), Nutrient Soup Report
Sheets for each student (pgs. 4446).
Objectives: Students will form a
hypothesis and conduct an
experiment that demonstrates how
excessive nutrients in water will
cause algae growth and will propose
ways to prevent algal blooms.
Background: Algae have no true roots, stems, or
leaves. They range in size from tiny, one-celled
organisms to large, multicelled, plantlike organisms.
Algae can be planktonic (mostly microscopic, singlecelled, free floating in the water column),
filamentous (forming chains, filaments, or colonies)
or plantlike. Although algae aren’t classified as
plants, they’re functionally similar to plants because
most algae are photosynthetic. They’re primary
producers and can directly convert the sun’s energy
to make food energy.
Although algae are natural and healthy components
of lakes and streams, producing oxygen that is vital to
aquatic life, they are “too much of a good thing”
when they grow and reproduce rapidly. The naturally
occurring elements nitrogen and phosphorus are
nutrients essential to plant and algae growth. But
too much of these nutrients in a water body can
stimulate an overgrowth of algae and aquatic plants.
Excessive algae growth prevents light from reaching
deeper water, harms aquatic life when toxic forms of
algae dominate, and poses an unpleasant nuisance to
people. When algae dies off in large amounts,
bacterial decomposers begin to break them down in
a process that uses up oxygen. Sometimes so much oxygen is consumed in the process that fish
and other aquatic organisms begin to die.
Excess amounts of nitrogen and phosphorus often enter water when household and
agricultural fertilizers are washed into streams and lakes after rainfall. Even household cleaning
products such as dishwasher detergents contain phosphorous.
42
Warm up: Explain that phosphorus and nitrogen are essential nutrients for plants, but that
excessive amounts of these nutrients cause algae blooms. Explain why excessive algae growth
harms aquatic life. Display some common household items and yard products that contain
nitrogen and phosphorus. Discuss the ways in which these products are used and how they
enter waterways.
Activity:
1. Divide students into groups.
2. Give each group two containers.
3. Have them label one container “Fertilizer” and the other “No Fertilizer” and identify their
containers with initials.
4. Have students fill each cup with pond water.
5. Add ten drops of liquid fertilizer or about ¼ tsp. dry fertilizer to the “Fertilizer” container.
6. Place the containers in a sunny window. Keep light and temperature conditions identical
for both types of container.
7. Cover the containers with plastic wrap.
8. Give each student a copy of the Nutrient Soup Report Sheet. Each group should make a
prediction about what they think will happen to the “Fertilizer” and “No Fertilizer” cups
during the experiment, and write their predictions on the sheet.
9. Over the course of 7-14 days, students should record daily observations of their containers.
Observations may include water color, water clarity, or scent.
10. When the experiment is over, students can dispose of the water in their containers by
emptying them onto the ground outdoors.
Wrap up: Within their groups, have students complete the Conclusions section of the
Nutrient Soup Report Sheets. Have students summarize their observations and some possible
reasons for what they observed. As a class, discuss the students’ hypotheses. Did the outcome
support their predictions? Discuss the possible limitations of the experiment – what might have
influenced the outcomes? What are some other variables that could be tested (use tap water
43
or aquarium water as an additional experimental unit, use varying levels of sunlight, etc.)? How
could the experiment be improved? Ask students to predict what might happen if you
continued the experiment and placed the containers in a dark closet where the algae did not
have access to sunlight. Ask students to predict what might happen if their trout were living in
the “Fertilizer” containers.
Extension: Examine samples of the pond water under a microscope at various times
throughout the observation period. Design posters advertising phosphorus free fertilizers and
detergents.
44
NUTRIENT SOUP REPORT SHEET PG 1
Name
Prediction
What do you expect to happen in the container labeled “Fertilizer”?
What do you expect to happen in the container labeled “No Fertilizer”?
45
NUTRIENT SOUP REPORT SHEET PG 2
Name
Observations
Record your observations of the two containers. Notice things like color of the water, whether or not it’s
clear, and how it smells compared to the other container and the previous day.
Day
1
2
3
4
5
6
7
No Fertilizer (control)
Fertilizer (experimental)
46
NUTRIENT SOUP REPORT SHEET PG 3
Name
Conclusion
Did you observe what you expected to in your prediction? Explain why or why not.
What might have influenced the algae growth or lack of algae in your containers?
What would you do to improve your experiment for next time?
47
Water Quality: Sum of the Parts
Adapted from the Project WET Curriculum and Activity Guide copyright by the Project WET
Foundation.
Standards:
Duration: 45 minutes.
Materials: Large poster board or
newsprint, colored pencils, pens or
markers, squares of construction
paper from the ‘What’s in the
Water’ activity, an assortment of
small classroom objects (erasers,
pencils, paperclips, notebook paper)
Objectives: Students will
distinguish between point and
nonpoint source pollution,
recognize that everyone contributes
to and is responsible for a river or
lake’s water quality, and identify
ways to reduce pollution.
Background: The quality of water in a river (or
lake) is, to a large extent, a reflection of land uses
and natural factors found in its watershed. If soil near
a river or lake naturally erodes, chances are the river
has sediment and turbidity problems. If the land has
stable vegetative cover, erosion is kept in check.
When humans settle and develop land, water quality
is affected. Breaking sod, cutting forests, building
cities, mining, and other land uses make an impact
upon water quality. Everyone bears responsibility for
the health of a watershed and the water systems
(rivers, lakes, wetlands, etc.) within a drainage basin.
Individual actions, both negative and positive, add
up. Understanding a river or lake’s water quality and
quantity involves investigating the condition of the
contributing watershed. If the watershed is polluted,
the river will likely be polluted.
Watershed investigations are conducted for many
reasons. Some investigations monitor changes in river and stream flows over time, to protect
fisheries, to regulate floods, or to meet seasonal demands. Other studies determine the best
method of protecting a river or lake from pollutants. One aim of a researcher might be to
determine which areas of a watershed contribute the highest percentage of contaminants. This
information is vital to policymakers and water managers when determining how best to spend
money for improvements. For example, most lake improvement projects address problems in
the watershed as well as those of the lake. It would prove fruitless to spend thousands (or even
millions) of dollars to clean up a lake, if problems in the watershed will only pollute the lake
again.
When watershed managers investigate land use practices that might affect the quality of water,
they are concerned with two general sources of pollutants: point and nonpoint. Point source
pollution involves pollutants that are discharged from, and can be traced back to, an
identifiable point or source, such as a factory’s discharge pipe or a sewage ditch. Nonpoint
48
source (NPS) pollution occurs when the source of a contaminant is unidentifiable; that is, the
pollutant can come from one of many places. Examples of nonpoint source pollution include
runoff from agricultural fields containing fertilizers and pesticides, motor oil filtering from
urban areas, and sediments from eroded stream banks. Surface runoff and ground water can
transport both point and nonpoint source pollutants. Since point source pollutants are
identifiable, they are easier to monitor. The protection of surface and ground water resources
from NPS pollution presents an enormous challenge because of the widespread and diverse
nature of the problem. Land and water managers rely on methods called Best Management
Practices, or BMPs, to describe land use regulations designed to reduce or eliminate NPS
pollution problems.
Preparation: Using a blue marker, draw a river down the center of the poster board, as
indicated. Create a grid dividing the paper into equal sized sections, creating one section for
each participant or group of participants. Each section should include some water and some
land. On the back of each section, write a number or letter in the corner so they can be
reassembled. It may help to match the sections that connect together side by side (e.g., label
the top 2 sections with a 1). Cut the sections.
Warm up: Determine student knowledge about watersheds by asking them to name several
major North American rivers (e.g., Mississippi, Columbia, Missouri, Hudson, and Rio Grande).
Use the Missouri as an example. Ask if anyone knows where it originates (the headwaters are
49
in southwest corner of Montana) and ends (empties into the Mississippi near St. Louis, MO,
which empties into the Gulf of Mexico near New Orleans, LA). Identify how many states does it
crosses or touches. Discuss some of the predominant types of land uses found along the
Missouri. Do students think these practices could affect the river? What do students think the
attitude of downstream state residents might be about the water received from their upstream
neighbors?
Activity:
1. Inform students that they have just inherited a piece of riverfront property, and a million
dollars. Have them list ways they could use the land and the money.
2. Pass out “pieces” of property, and drawing pens and pencils. Explain that the blue is water
and the blank space is land they own. They have one million dollars to develop their land as
they wish. They can farm or ranch; build resorts, homes, shopping malls, factories, plant
forests, log, mine, create a state park – whatever they like. While students are drawing,
pass out an assortment of the pollution tokens and classroom objects. Attempt to give the
students ‘pollution’ that correlates with their development.
3. When students have completed their drawings, ask them to look in the upper left-hand
corner of their property for a number. Explain that each piece is actually a part of a puzzle.
Starting with number one, have students assemble their pieces. They will construct the
stream pathway and adjacent land area in proper order.
4. Have students describe how they developed their land and how they used water. They
should identify any of their actions that polluted or added materials to the waterway. Tell
the students that each of their contributions to the river with an item from their desks (e.g.,
book, piece of paper, pen, pencil).
5. Tell students to take their tokens and line up next to their pieces of river front property.
They are going to pass their pollution pieces downstream. Have them announce what kind
of pollutant they are holding before they pass it on. The ones will pass their item(s) to the
twos, the twos will pass everything to the threes, and so on, until the last students are
holding all the items.
Wrap up: After all the items have reached the final students, discuss the activity. How did
those students toward the middle or at the end of the river feel? What about their property use
plans? Could a student downstream be affected by the actions of a student upstream? Could
upstream users alter the water quality of those downstream? Tell students to reclaim their
50
items. Explain that the items that are easily identifiable simulate point source pollution. The
pollution tokens will be difficult to claim, because these kinds of pollutants originated from
multiple sources. Tell students these represent nonpoint source pollution. Ask the students to
identify ways they can reduce the input of pollution into the river by changing the way their
land is managed. Introduce the importance of buffer strips. Explain how a vegetated buffer
that separates the river from the land development can prevent nonpoint source pollutants
(like gas, oil, and lawn chemicals) from washing off from parking lots and lawns every time it
rains. A good vegetated buffer is wide and has a variety of different kinds of plants on it,
ranging from ground covers to bushes and trees. A good buffer can do a lot to help prevent
nonpoint source pollutants from reaching the river!
51
Water Quality: Additional Activities
Aquatic WILD Curriculum
Water Canaries, pg. 63
Objectives: Students will identify several aquatic organisms and assess the
relative environmental quality of a stream or pond using indicators of pH, water
temperature, and the presence of a diversity of organisms.
Riparian Retreat, pg. 175
Objectives: Students will describe habitat characteristics of riparian areas,
identify animals that inhabit them, and state the importance of riparian areas to
wildlife and humans.
Dragonfly Pond, pg. 282
Objectives: Students will evaluate the effects of different kinds of land use on
wetland habitat, and discuss and evaluate lifestyle changes to minimize
damaging effects on wetlands.
52
Food Webs: Aquatic Web of Life
Standards:
Duration: Part I: 30-45 minutes,
Part II: 60 minutes
Materials: 3x5 index cards for each
student with holes punched in two
adjacent corners, ball of yarn.
Objectives: Students will identify
components of the ecosystem,
describe connections between
components of the ecosystem,
discuss hypothetical changes in the
ecosystem and the effect of the
change, and explain how energy
flows through the ecosystem.
Background: A river, including its riparian zone, is a
living community. The organisms within this
ecosystem are connected in what is often called “the
web of life.” How can so many different organisms
occupy the same ecosystem without wearing out all
of the resources? The answer is that each organism
has evolved to have its own niche, or role in the
community. W.B. Saunders made the analogy that
“the habitat is the organism’s ‘address’, and the
niche is its ‘profession’, biologically speaking.” With
all of these different ‘professions,’ each species
contributes to the health of this interwoven
community.
One way the animals living in and around a river are
connected is through eating relationships. All life
depends on the sun and the ability of green plants to
use sunlight to synthesize simple sugars from carbon
dioxide and water. Through this process, known as photosynthesis, plants take energy from
sunlight and make it available to animals. Plant eaters, or herbivores, eat the plants directly;
animal or flesh eaters, carnivores, eat both herbivores and other carnivores, thus forming a
food chain.
A food chain is a simplified way of showing energy relationships between plants and animals in
an ecosystem. For example, a food chain of sun → algae → mayfly → rainbow trout → bald
eagle shows that the sun provides energy to the algae (producer), which in turn is eaten by a
mayfly (primary consumer and herbivore). The mayfly then becomes energy for a rainbow trout
(secondary consumer and omnivore). Finally, a bald eagle (tertiary consumer and carnivore)
eats the trout. However, this is a very simplified version of what actually happens in nature.
Rarely does an animal eat only one type of food; most animals consume many types of food
and are in turn consumed by many types of predators. A food web, as opposed to a food chain,
is a more accurate way of demonstrating the interconnections of various organisms in an
ecosystem. A food web extends the food chain concept from a simple linear pathway to a
complex network of interactions.
53
Organisms in an ecosystem are connected in additional ways beyond the food web. They can
also provide habitat for other species. For example, trees provide habitat for nesting birds and a
beaver’s dam creates a pool in the river, providing habitat for certain aquatic insects.
Furthermore, species may rely on others to aid in some way with reproduction. Certain
flowering plants need honey bees and other insects to carry pollen from one flower to another.
Additionally, species of birds help spread a cottonwood’s soft seeds while using it to build a
nest each spring.
The web of life created in this activity suggests that all living things are connected. No matter
how unrelated organisms may seem, they are, in fact, connected.
Warm up: Write out John Muir’s quote, “When you try to change a single thing, you find it
hitched to everything else in the universe,” on the board. Ask students to share their ideas
about what Muir meant. Do the students agree? Prompt them to list examples of connections.
Activity:
Part I.
1. Discuss the terms ecosystem, producer, consumer, herbivore, carnivore, omnivore,
scavenger, and niche. Ask the class to brainstorm all the living components they think they
would need to make a healthy river ecosystem. Write down the list on the board. Refer to
the example list on page… for further ideas.
2. Explain to your students that they will get to become an expert on one species in an aquatic
ecosystem. Assign each student to one of your listed species and give each an index card.
The students must research their species.
 If they are assigned an animal, have them research (1) what the animal eats, (2) what
eats the animal, (3) if it is an herbivore, carnivore, omnivore, and/or scavenger, (4) what
niche the species fills in the ecosystem, and (5) any fun/ weird trivia about the organism.
 If they are assigned a plant, bacteria or fungi have them research (1) what the species
gives others, (2) what eats the species, (3) if it is a producer or decomposer, (4) what
niche the species fills in the ecosystem, and (5) any fun/ weird trivia about the organism.
3. Students should record this information either on one side of their card or in paragraph
form on a separate piece of paper. On the other side of the card, the student should display
a picture of the organism.
54
Part II.
Display the list of aquatic food web members the class came up with. Go through the list with
each student giving a mini-presentation to the class describing their animal or plant and its role
in the ecosystem. Create an index card that represents the sun.
1. Each student gets a piece of yarn to attach to their card, making a name tag to wear around
their neck. Have each student wear their card so that the photo of their organism is visible.
The class then gets up and stands in a circle, preferably outdoors. Ask the class what all life
needs to grow – the ultimate source of energy, the sun. The class leader (or an assigned
student) can be the sun. The ball of yarn starts here.
2. What would be next in the chain? It would be some sort of producer since the sun is what
provides energy to the producer, allowing it to make food. While holding on to the end of
the ball of yarn, the sun passes the ball to someone with a plant/producer card.
3. Continue through the web. The ball of yarn must then be passed to a species that depends
on that plant – either for food or for habitat (to nest in, etc.). Go through the whole web,
making sure everyone has become ‘woven’ into the web. It is okay to go to one member of
the web more than once.
4. When all the cards have been used, ask the “sun” to tug gently on the yarn. As each
member of the web feels the tug, they should also start tugging. Soon everyone is tugging,
showing the connectivity between all the organisms in the ecosystem.
5. Have the class stop tugging and pull the yarn taut. Now have one member drop the yarn. As
each person feels the tightness go away, they also drop the yarn. Soon no one is holding the
yarn. This shows the web ‘unraveling’.
Wrap up: Regroup and discuss the following questions…





What happens when we remove a link in the aquatic ecosystem? (Organisms that
depend on it are affected)
Would the effect of losing a ‘link’ be more or less dramatic if there were fewer members
in the system. (Should be more dramatic)
What can we say about the relationship between how many parts the system has (its
complexity or diversity) and how stable it is? (In general, complexity makes it more
stable.)
How do humans play a role in the web?
What can we do to help ecosystems stay healthy?
55
Extension: Re-create your web of life on a bulletin board visible to the school. Post the class’s
species and yarn to link them. Describe the links between two species on covered tabs so that
other students have a chance to guess and then discover the connection.
Create concept maps depicting the relationships between ten organisms from the aquatic web
of life.
 Have the students choose ten of the organisms from the web activity.
 The students then create a concept map to demonstrate the relationships between
these organisms.
 To create a concept map, the students should write down the organisms’ names on a
piece of paper. The names should be spread out in the shape of a circle on the sheet of
paper. This will allow room for the students to draw linkages between the organisms.
Draw a box or circle around each name to designate it.
 Link the organisms with an arrow and verb or phrase describing the relationship such as
‘eats’ or ‘lives in’.
Related Reading:
The Magic School Bus Gets Eaten: A Book About Food Chains by Pat Relf
Pass the Energy, Please! By Barbara Shaw McKinney
River Discoveries by Ginger Wadsworth
Scavengers and Decomposers: The Clean Up Crew by Pat Hughey
Examples of Aquatic Web of Life Members:
Bacteria
Algae
Sedges
Cottonwood tree
Ponderosa pine
Dogwood
Willow
Huckleberry bush
Scud
Mayfly
Dragonfly larva
Aquatic worm
Aquatic snail
Water strider
Dace
Rainbow trout
Largemouth bass
Creek chub
Leopard frog
Tiger salamander
Garter snake
Bullfrog
Great blue heron
Wood duck
Bald eagle
Pelican
Osprey
Killdeer
Beaver
River otter
Muskrat
56
Food Webs: Water bug Hunt
Adapted from the Salmon in the Classroom Curriculum Guide copyright by the Michigan
Department of Natural Resources.
Standards:
Duration: 45 minutes
Materials: macroinvertebrate
collection kit (preserved specimens,
macroinvertebrate sorting sheet,
shallow trays, magnifiers, ice cube
trays, siphons, petri dishes,
pinchers, collection nets - available
from the Aksarben Aquarium),
sample of pond water, small
aquarium tank, drawing paper,
colored pencils, crayons or markers.
**This activity can be scheduled to
coincide with a school visit by
Nebraska Game and Parks
Commission staff, who will provide
pond water and lead the activity.
School visits can be scheduled in
April or May. If interested, please
contact your TIC coordinator to
book a visit prior to the Christmas
break.
Objectives: Students learn to
identify a variety of
macroinvertebrates and understand
their role in the aquatic ecosystem.
Students will also gain knowledge of
how these organisms serve as
biological indicators for the overall
health of these systems.
Background: Macroinvertebrates are large enough
to see with the naked eye (macro) and have no
backbone (invertebrate). They are big, no-backbone
bugs. Benthic macroinvertebrates live in the benthos
or bottom of a body of water and include insect
larvae, crustaceans, mollusks and worms. The
presence or absence of macroinvertebrates in an
aquatic ecosystem is an indicator of the overall
health of the ecosystem. Different organisms can
tolerate different levels of pollution. Some are very
sensitive to pollution and their presence indicates the
water quality is good. Other organisms are pollutiontolerant and their abundance usually signifies poor
water quality.
Macroinvertebrates are an important part of the food
web in an aquatic ecosystem. Many species depend
on them as a source of food. For example, the pallid
sturgeon, an endangered species in the Missouri
River, is a bottom-dwelling species that often relies
on macroinvertebrates as a food source. Most
species of the sunfish family, such as largemouth bass
and bluegill, feed on crayfish, larval and adult insects,
and snails either as juveniles or throughout their
lives. Macroinvertebrates also serve an important
ecological function by digesting organic material such
as leaves and dead and decaying plant materials by
recycling their nutrients back into the environment
and making them available to plants and animals to
use.
Preparation: Collect samples of pond water that
contain abundant organisms. It is helpful to have a
small aquarium in the classroom to hold the water.
57
For the aquarium, collect bottom materials such as soil and detritus. Aquatic plants can also be
transferred to the aquarium.
Warm up: Discuss the importance of macroinvertebrates in an aquatic food web. Ask
students what macroinvertebrates consume and what consumes macroinvertebrates. In
nature, macroinvertebrates are a primary source of food for trout. Assessment of the
macroinvertebrate community in a stream can indicate whether it has the water quality and
habitat to support trout populations. Divide students into small groups.
Activity:
1. Give each group a sample of pond water to pour into a shallow tray.
2. Allow students time to examine the water and remove specimens to place into
compartments of the ice cube trays.
3. Have students identify each type of macroinvertebrate they collected using the sorting
sheets and preserved specimens.
4. Allow students to select their favorite specimens, either from their collections or the
preserved samples, and have them make an illustration of their selection.
5. Ask students to write a report about the life cycle and habitat of their specimens. Is their
specimen a preferred food for trout?
Wrap up: Were there a lot of pollution-sensitive organisms? This indicates the aquatic
ecosystem is of good water quality. Such organisms may include Fishfly Larva, Snipefly Larva,
Dobsonfly Larva, Caddisfly Larva, Mayfly Nymph and Stonefly Nymph. A stream with this
macroinvertebrate community would be good habitat for your trout!
Were there a lot of less sensitive organisms? This indicates the water quality is neither really
good nor really bad but is somewhere in the middle. This tells us the water quality is not too
degraded but that some problems exist. Indicator organisms include Alderfly Larva, Flatworms,
Cranefly Larva, Damselfly Nymph, Dragonfly Nymph, Aquatic Sowbug, Freshwater Scud, Aquatic
Snails and Water Mite.
Were there a lot of pollution-tolerant organisms? This indicates the water quality is poor and
degraded. What could be the cause of the water being degraded? Indicator organisms include
Blackfly Larva, Horse/Deerfly Larva, Midge Larva, Backswimmer, Giant Water Bug, Water Penny,
Water Boatman, Waterstrider, Whirligig Beetle, Whirligig Beetle Larva, Riffle Beetle, Aquatic
Worms, Leech, Crayfish and snails. A stream with this macroinvertebrate community is not
ideal trout habitat.
58
Extension: Invite a member of the local Trout Unlimited chapter to visit the classroom and
discuss trout feeding habits, and how studying what kind of macroinvertebrates trout eat can
help fly fishermen to catch fish.
Create a class mural using the macroinvertebrate illustrations. Include illustrations or photos of
other components of the food web, and draw connections between the organisms.
Related reading: My Healthy Stream a publication of Trout Unlimited, available through the
Aquatic Education Program at Nebraska Game and Parks Commission.
59
Food Webs: Additional Activity
Aquatic WILD Curriculum
MicroOdyssey, pg. 91
Objectives: Students will forms of microscopic life that live in water and describe
how various aquatic organisms are interrelated.
60
Fish Anatomy: What makes a Fish – Trout Dissection
Standards:
Duration: 60 minutes
Materials: Whole trout (contact the
TIC coordinator to arrange for
trout), Dissecting kit (available from
Aksarben Aquarium - contains
scissors, scalpels, tweezers,
magnifying glasses), latex gloves,
microscope, paper towels,
newspapers, fish anatomy
worksheet (pg. 70 or 71), trout
anatomy crossword (pg. 73).
Objectives: Students will explore
the internal and external anatomy
of a trout, and explain how fish are
specifically adapted to their
environment.
Background: The term anatomy refers to the
structure of living things – plant, animal, or any of
their parts. Generally each cell, tissue, and organ of a
living being has a specific function. For example, our
opposable thumb is a finger that allows the hand to
refine its grip and hold objects it may not be able to
do otherwise.
External Anatomy
Coloring
Despite all of a trout’s amazing adaptations to
aquatic life, perhaps its most notable feature is its
coloring. Rainbow trout are so called because of
their red lateral stripe. These trout (of the
Oncorhynchus genus) have black spots against a light
background - not to be confused with species of the
Salvelinus genus, which have light spots on a dark
background (bull or lake trout). However, a trout’s
appearance will vary from stream to stream, as
water temperature and diet both affect its
coloration.
Scales
Trout look so smooth that you might think they do not even have scales. Trout do have scales; a
specific type of scale known as a cycloid scale. These scales are quite thin and partially
embedded in the skin in an overlapping pattern that reduces friction when fish are swimming
forward. Thin scales provide an advantage in regulating buoyancy, because they are light. The
thinness increases speed, but does not provide a very strong shield from predators. The scales
of more primitive fish species often are thick and armor-like, providing more protection from
predators. A trout’s scales are oval and have growth rings (circuli) that are similar to a tree’s
annual rings and are deposited throughout the year. A tree’s rings appear close together when
growth is slow; usually during a dry season. Circuli also appear close together when growth
slows during the winter months when food is scarce and metabolism slows. Likewise, when
food is abundant the spacing increases between a trout’s circuli.
61
Fins
Fins are appendages used by fish to maintain position, move, steer and stop. Most fins are
composed of fin rays covered by skin. The fin rays are made from cartilage provide support and
are necessary for fin movement. Some species have bony spines in place of fin rays on some of
their fins. The spines act as a defense against predators. Trout have three unpaired fins: the
dorsal fin, anal fin, and caudal fin. The dorsal and anal fins are essential in helping the fish stay
upright. The caudal fin is the ‘tail’ of the fish and thrusts the fish through the water. It also acts
as a rudder to steer the fish. The shape of the tail fin varies by species and provides a clue when
trying to identify trout. For example, lake trout have deeply forked tails while brook trout have
relatively square tails. Most trout species have a tail that is slightly forked. Trout also have two
paired fins: pectoral fins behind the gills and pelvic fins below and behind the pectoral fins. The
pectoral fins act as brakes and help with side-to-side movement. The pelvic fins help with up
and down movement. Trout also possess an additional adipose fin which lacks fin rays and has
little known purpose. This fin is sometimes removed by hatcheries as a means of distinguishing
hatchery raised fish from wild populations.
Mouth
The mouth is an important tool to the trout. It is used to feel objects, making up for the lack of
hands. The trout’s mouth is covered in teeth. Teeth are even found on the roof of the mouth
and on the tongue! All of these teeth are not used for chewing but are instead used for
grabbing prey. By looking down the mouth of a trout, you can get a great view of the gills. Fish
draw water through their mouths into their gills.
Gills
Trout take in oxygen and give off carbon dioxide, just like us. However, they have gills to extract
the oxygen from water and to eliminate (exhale) carbon dioxide back into the water. Opercula
are hard plates that cover the fragile gills on each side of the head. Trout take in water through
the mouth and as water runs along the gills, the opercula open to allow the water to pass out of
the fish. Gills are composed of four gill arches, each arch with both gill rakers and gill filaments.
The gill filaments are the principal component of gas exchange, the part that actually takes in
oxygen from the water and eliminates carbon dioxide. Gill rakers are bony projections which
point forward and inward from the gill arches. They strain out unwanted particles from the
water to prevent injury and help strain out potential food, such as plankton.
Sensory Organs
Lateral Iine
Have you ever wondered how a school of fish manages to move together so smoothly and
quickly? The lateral line allows each fish to instantly sense a change in water pressure and stay
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in-line with the rest of the school. The lateral line is a series of sensory pores along the midline
of each side of a fish. Trout use this feature to detect water movement, avoid objects in their
path, and sense certain chemicals in the water, including pheromones (special chemicals given
off to attract a mate). Scales along the lateral line are unlike any other scales on the fish. They
have small canals that allow water to flow along the sensory structures of the organ. Trout (and
other Nebraska fish) have one lateral line on each side of the body, unlike some other species
of fish that have two.
Vision
With eyes on the sides of their head, fish can see in front, on the sides, and most of the way
behind them. Fish do not have eye lids but have a thicker cornea than we do. Trout have large
pupils which allow light to enter the eyes. Their pupils do not constrict with an increase in
ambient light, which is probably why trout tend to stay away from sunny areas. Until trout can
talk we won’t know if they can see color like we do, but it would be a good guess. Fish retinas
contain both rods which help see in dim light and cones which help detect color. Additionally, it
seems fish are more attracted to brightly colored lures than those that are dull in color. The
optic lobes of a fish’s brain are relatively large in comparison to the rest of the brain, proving
how vital sight is to the fish and its survival.
Smell
Olfactory organs are located in specialized nasal sacs in the snout of the trout. Water is brought
into the sacs via nares or nasal openings. The nares are covered with flaps that guide water into
the olfactory sac, which contains the smell receptors. Sense of smell is important for migratory
species. Migratory fish become imprinted on the smell of the stream where they were born.
They follow smells to find their way home to spawn.
Ears
Fish ears? While trout don’t have external ears, they do have internal ears. It is believed that
because sound moves so quickly through water fish do not need an external opening to “catch”
sound like we do. The inner ear is composed of chambers that contain small pieces of bone. As
the trout moves through the water, the bones move and hit against nerve endings sending
messages to the brain. The otolith is a free-floating oval-shaped bone in the ear often used to
accurately age fish. Growth rings can be clearly distinguished on these bones, similar to rings on
their scales. A trout’s inner ear is also an organ of equilibrium, helping the fish keep its balance
and stay upright.
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Internal anatomy
Skeletal and Muscular Systems
The skeletal and muscular systems are closely linked, providing physical support and overall
shape to trout. Muscular contractions, made possible by the backbone’s support, make the
body bend for swimming and turning and enable the fish to put on the sporadic bursts of speed
often needed to catch its food. Muscles constitute 40% of a fish’s weight. Similarly, an average
human adult male is made up of 40-50% of skeletal muscle, and an average adult female is
made up of 30-40%. The muscle is the part of the fish that we eat.
Circulatory System
A trout’s heart is located at the base of the throat in front of the abdominal cavity. The trout
has a single pass circulatory system in which blood goes from the heart to the gills and then to
the rest of the body. This differs from our circulatory system, called a dual pass circulatory
system. Our circulatory system sends blood to the heart twice in one pass through the body –
from the heart to the lungs, back to the heart, and then to the rest of the body. Unlike warmblooded animals, fish lack bone marrow so fish make blood cells in the kidney and the spleen.
Swim Bladder
Energy expenditure is kept to a minimum by maintaining neutral buoyancy, which trout do by
means of the swim bladder. The swim bladder is a long, thin sac located underneath and
parallel to the kidney. Trout inflate the swim bladder by taking in air through the mouth and
forcing it through a duct into the bladder. Conversely, they can deflate the swim bladder by
‘burping’ out air. This allows the fish to sink into deeper waters.
Digestive System
Trout have a simple digestive system, beginning with their mouth. A trout’s mouth is covered
with short, pointed teeth to help it hold larger prey (not to chew!). The teeth are slanted
towards the throat so as to prevent any prey from escaping. Food passes from the mouth
through the esophagus and to the J-shaped stomach. The stomach is broken down into two
regions: the cardiac and pyloric regions. The cardiac region, near the heart at the top of the
stomach, releases enzymes and acid to aid in digestion. The pyloric region, at the back of the
stomach, grinds and pushes the food into the intestine. At the junction of the stomach and
intestine, there are hollow, finger-like projections called pyloric caeca. This is the primary place
that digestion and absorption take place.
The liver is a large, dark red or brown organ located in front of the stomach. The liver produces
bile, a green fluid released into the intestine via the bile duct, to neutralize stomach acids. The
gallbladder, a small greenish sac, sits atop the liver and stores bile.
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Nervous System
As in most vertebrates, the trout’s nervous system is made up of the brain, spinal column, and
nerves. The trout’s brain is encased in a bony skull. The brain can be further broken down into
different lobes. The olfactory and optic lobes of the brain process information from the nostrils
and eyes. The semi-circular canals help maintain balance. The cerebellum controls muscle
movement, and the medula controls vital processes, such as heart rate and respiration. Just as
in humans, nerves send impulses to the brain, which reacts to the stimuli.
Excretory System
The byproducts of metabolism and digestion are removed from the body by both the excretory
system and structures of the respiratory system. The excretory system works to excrete urine
while ammonia is excreted via the respiratory system. It is diffused from the gill filaments
during respiration. The kidney is the main excretory organ, although it also serves in the
processes of osmoregulation (see below) and blood formation. It develops in the trout embryo
as a set of paired structures, which unite in the adult trout to become one obvious organ, dark
brown to black in color. It is located beneath the vertebral column in the abdominal cavity.
Because the trout kidney is primitive, it is incapable of excreting nitrogenous wastes like
ammonia. Instead, a part of these compounds is deposited under the skin of the fish in the form
of guanine. It is this guanine that reflects light and renders the fish silvery.
Reproductive Structures
Increase in day length and rising water temperatures are two important factors that influence
the full development of the reproductive structures. Rainbow trout can attain sexual maturity
in one year, but usually require two or three. The gonads, or reproductive organs (testes and
ovaries), can be identified easily in adult trout. Both ovaries and testes are paired structures
suspended from the back (dorsal side) of a trout by a thin membrane. The male reproductive
glands are off-white in color and smooth in texture, consisting of tubules that contain semen. In
females, the ovaries produce ova, which are extruded through a pore in front of the urinary
opening.
Preparation: If there are enough trout to have students work in small groups (3 – 4), give
each group a dissection kit, newspaper to cover their desk, and gloves for each student. If you
only have one trout, choose a location where all students can view the dissection clearly. Cover
the surface with newspaper and prepare all the materials in a convenient area (have reference
sheet in view).
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Display the diagrams of a fish’s external and internal anatomy (page 62) on the board or hand
out copies of the diagrams for the students.
Warm up: Write the term “anatomy” on the board. Ask your students what the term means
(the bodily structure of a plant or an animal or of any of its parts). Tell the students that they
have the opportunity to study the parts of a real trout by conducting a dissection. Explain to the
students that through dissection, doctors and veterinarians learn about the body parts of
people and animals.
Activity:
External Anatomy
1. Slime. Have students feel the fish’s skin and discuss what purpose the slime serves. It
protects trout from fungus, parasites and other diseases. Slime is also an anti-abrasive,
helping trout slip over rocks and a lubricant, enabling ease of movement through water.
2. Scales. A trout has cycloid scales. Why do fish have scales? Use a magnifying glass to see
how the scales are arranged. Are there more now than there were when it was young? Fish
have the same number of scales their whole life. They build rings upon their scales, similar
to the rings of a tree. Scales offer protection to the fish (though a trout’s scales are not very
thick). Scraping the skin with a scalpel, remove some of the scales so you can look at the
rings under a microscope. Observe the pattern of the scales and growth rings on the scales.
3. Color pattern. Discuss the function of coloration and the advantages of being dark on top
and light on the belly. Why does the fish have spots? Throughout its life? The dark on the
top camouflages the trout with the stream bed from predators above the water (such as
eagles or osprey). The color of its belly camouflages it from predators below the fish (such
as otters). Spots help camouflage it among the rocks at the bottom of the stream. Young
trout have vertical stripes when they are a couple inches long. Eventually they fade and
spots appear.
4. Shape. Have students describe the fish’s overall shape and how this is beneficial to the fish.
Trout are quite streamlined, helping them to swim fast.
5. Fins. Look at the placement of the fins. Imagine the fish swimming in the water. How does it
move? How are the fins used? Note the range of movement of each fin – pectorals can
rotate 180° while others are not as flexible. Identify each fin – dorsal, adipose, caudal, anal,
pectoral and pelvic. Dorsal and anal: keep the fish from rolling onto its side. Caudal: thrusts
fish forward and acts as rudder to steer. Pectoral: act as brakes and help with side to side
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movement . Pelvic: helps with up and down movement. Adipose: no known use. Only fins
with bony rays can move. The rays are attached to muscle in the fish. Allow students to feel
the bony rays that support the fins.
6. Lateral Line. Observe the lateral line. Discuss what it is used for and how it works. It is a
sensory organ (series of pores) running along the midline on each side. It is used to detect
water pressure, avoid objects in their path, and sense certain chemicals in the water,
including pheromones (special chemicals given off to attract a mate).
7. Eye. Note the size of the eye (relatively large) and the large pupil. What does this tell us?
Size tells us how important vision is to trout.
8. Eyelid. Note that there is no eyelid. Have them observe the tough, clear membrane that
covers the eye. Rotate the eye in the socket with your finger. Trout can move each eye
independently!
9. Lens. Remove an eye by cutting the tissue behind it, holding it into the bony socket. Slice
into the eye and remove the lens. It is a small, hard ball in the center of the eye. The round
lens allows the fish to see in all directions at the same time. In humans the lens is fairly flat
or dish-like. Our eyes are capable of changing the curvature of the lens to focus at varying
distances (flatter for long-range focusing, more curved for shorter range). Fish cannot
change the curve of their lenses.
10. Nostril/Nare. Locate the nostrils. Describe the large olfactory lobes that are located in the
brain. Ask students to speculate why a trout’s smell receptors are so highly developed. It is
believed sense of smell helps a fish return home when it is spawning. Smell may also help
find food and avoid predators.
11. Mouth. Open the mouth and note the color of the gums (rainbow and steelhead gums will
be light in color). Make a note of how wide the mouth can open and have them comment
on why this is so. Trout feed on small prey – so they have a small mouth! The mouth is also
used for breathing. In low oxygen conditions, fish can actively pump water over gills by
opening and closing the mouth. Demonstrate this with the fish’s mouth, relating it to the
action of a pump. The gill arches can be seen by looking down the fish’s mouth. Use a probe
to separate the arches and explore how they are arranged.
12. Teeth. Have volunteers feel the teeth along the gum margins and on the roof of the mouth.
Ask students what function these teeth perform. Are they used for chewing? Have students
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feel the fish’s tongue. Is it similar to our tongues? The teeth are used for grasping and
holding prey. The tongue has teeth on it as well to help the fish swallow.
13. Operculum. Place the fish on its side and look at the operculum—the bony plates which
protect the gills. Lift the operculum and look at the gills.
Internal Anatomy
1. Gills. Cut the operculum away from its base, exposing the gills.Remove the gills by cutting
the upper and lower attachments of the arch. Look at the gill rakers, the bony projections
along the inside curve of the arches. Observe the large surface area provided by the gill
filaments and the thin tissue which allows blood vessels to come into contact with the
oxygen in the water. Compare and contrast gills and lungs.
2. Carefully cut the fish open using the scissors or scalpel. Cut from the vent (opening below
the anal fin) along the underside of the trout.
3. Before moving any organs, let students observe how all the internal organs fit together.
Look for the thin transparent membrane that encloses the organs.
4. Swim bladder. Look for the swim bladder. It is made of very thin tissue and is located in the
upper body cavity, below the kidneys. It will be less developed in small fish and since it will
not be inflated, it may be hard to find. If you can’t find it, point to its location and discuss its
function.
5. Muscle. Cut through the fish to expose the backbone and muscles and have students note
the arrangement of muscle mass. This is the part of the fish that we eat.
OPTIONAL:
1. Gonads. The male reproductive organs will be a flaccid white or orange tissue near the
intestines. Eggs may or may not be noticeable in females. Both will vary in size depending on
the maturity of the fish.
2. Kidneys. Put the fish on its back and find the kidneys, located just under the backbone. It will
look like only one, though there are two fused together. They are thin, dark in color and run
the whole length of the body cavity. Call on a volunteer to discuss the function of the kidneys
in our body. What do you think they do in a trout? They filter wastes from the blood stream
and also manufacture blood. Two ureters leave the kidney then unite into a single tube,
which enters the bladder.
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3. Esophagus. Investigate the digestive tract by starting in the mouth and following the route
that food would take. Put the probe through the mouth and into the esophagus to show the
beginning of the route.
4. Stomach. Follow the course of the stomach using your finger or the probe. The first area of
the stomach is called the cardiac stomach; this is where digestion begins. Have students
notice the different kinds of tissue that make up the stomach. The pyloric stomach is that
portion from which the pyloric caeca project. It begins at the bend below the cardiac
stomach, and is made of different tissue. Discuss how the stomach area is increased by the
pyloric caeca. How does this improve the function of the stomach? There is more surface
area to absorb nutrients, sugars and proteins.
5. Cut open the stomach to see what it looks like as well as what the fish was eating.
6. Intestines. The intestines provide the last chance to extract nutrients from food. Notice the
network of blood vessels which are used for nutrient exchange. Follow the intestines to the
anal opening, where waste products are eliminated.
7. Spleen. Lift the stomach to show the spleen. It is a reddish organ found at the end of the
cardiac stomach. The spleen stores and forms blood.
8. Liver. The liver is in front of the stomach. Discuss the liver’s role in digestion. Point out the
gallbladder, a mass of darker tissue on the liver. Discuss the role of the gall bladder. The liver
manufactures bile, which digests fat. The gallbladder stores bile.
9. Heart. Move the liver to locate the heart— which is almost literally in its mouth. You should
be able to make out the different chambers. Point out that the gills, heart, and liver being
close together is no accident. Blood pressure is best near the heart (pump). Blood is filtered
by the liver and absorbs oxygen from the gills.
Wrap up: Ask the students if there is any part of the fish that does not have a function? All
parts of animals have a function; however, occasionally, animals evolve and no longer need
some parts of their bodies. In trout, the adipose fin serves an unknown purpose. In humans, our
appendix is not needed. Discuss with students how the trout’s body parts and functions
compare to a mammal’s. Create a chart comparing organ purpose in each organism.
Distribute the fish anatomy diagram and crossword puzzle to students.
Related Reading:
What is a Fish? by Bobbie Kalman
Adapted for Habitat, Minnaqua Leaders Guide
http://files.dnr.state.mn.us/education_safety/education/minnaqua/leadersguide/chapter_2/2_
6_adapted_for_habitat.pdf
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70
TROUT ANATOMY WORKSHEET I
Name:_______________________________
Courtesy of Idaho Trout in the Classroom Curriculum
71
TROUT ANATOMY WORKSHEET II
Name:_____________________________________
Courtesy of Idaho Trout in the Classroom Curriculum
72
TROUT ANATOMY ANSWER KEY
Courtesy of Idaho Trout in the Classroom Curriculum
73
TROUT ANATOMY CROSSWORD
Name____________________________________________
Courtesy of Idaho Trout in the Classroom Curriculum
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Fish Anatomy: Fashion a Fish
Adapted from Project WILD Aquatic Activity Guide copyright by the Council for Environmental
Education. For more information about Project WILD contact Nebraska’s Project WILD
Coordinator at [email protected].
Standards:
Background: All animals are the product of
Duration: 30-45 minutes
countless adaptations that occurred over long
periods of time. Those adaptations are, for the most
part, features that increase the animals’ likelihood of
surviving in their habitat.
Materials: One copy of adaptation
cards (pgs. 77-79), cut and
separated, paper or posterboard,
markers, paint, crayons or colored
pencils.
Objectives: Students will describe
adaptations of fish to their
environments, describe how
adaptations can help fish survive in
their habitats, and interpret the
importance of adaptation in
animals.
When a habitat changes, either slowly or
catastrophically, the animals with adaptations (that
allow them many options) are the ones most likely to
survive. Some species have adapted to such a
narrow range of habitat conditions that they are
extremely vulnerable to change. These species are
usually more susceptible than other animals to death
or extinction.
In this activity, the students design a fish. Students
will choose the adaptations that their fish will have.
As those adaptations become part of the fish’s
design, the fish becomes better suited to the habitat in which it lives. Because of the variety of
conditions within each habitat, many different fish can live together and flourish.
Warm up: Begin a discussion by asking the class to define what an adaptation is. An
adaptation is a characteristic of an organism that increases its chance of survival in its
environment. How do species adapt? Those individuals that are best equipped for life in a
specific habitat are more likely to survive to the age where they can reproduce. Therefore, their
genes and characteristics are more likely to be carried on. Over countless years those
characteristics become common in the species.
Activity:
1. Assign students to find a picture or make a drawing of a species of animal that has a special
adaptation. For example: a picture of a giraffe with a long neck for reaching vegetation in
tall trees, or an owl with large eyes that gather light to aid with night vision.
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2. Conduct a class discussion on the value of different kinds of adaptations to animals. As part
of the discussion, ask the students to identify different kinds of adaptations in humans.
3. Collect the students’ pictures or drawings of adaptations. Categorize them into the
following groups:
• protective coloration and camouflage
• body shape or form
• mouth type or feeding behavior
• reproduction or behavior
• other (any categories the students establish, in addition to the four above that will be
needed for the rest of the activity)
4. Divide the adaptation cards into five groups of four cards each: one coloration, one mouth
type, one body shape, and one reproduction in each group.
5. Break up the classroom into five groups. Pass one complete set of cards to each group of
students. There might be five groups with four to six students in each group.
6. Review the adaptations by asking each group what they think the advantages are to the
adaptations they were given. Record a list of the advantages to each adaptation on the
board.
7. Ask the students to “fashion a fish” from the characteristics of the cards in the set they
receive. Each group should:
• create a drawing or painting that represents their fish
• name the fish
• describe and draw the habitat for their fish
Wrap up: Ask each group to report on the attributes of the fish they have designed, including
identifying and describing its adaptations. Ask the students to describe how this kind of fish is
adapted for survival.
Extension: Have the groups create the habitat that their fish would be best suited for.
Students can draw, paint, make a diorama, or outfit a fish bowl. Each group reports on why this
habitat would be best for the fish.
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Invent an animal that would be adapted to live in your community or a different and exotic
habitat of your choice. Consider mouth, shape, coloration, reproduction, food, shelter, and
other characteristics. Draw and describe your animal.
Related reading:
Amazing Fish by Mary Ling
Exploding Ants: Amazing Facts About How Animals Adapt by Joanne Settel
What is a Fish? by Bobbie Kalman
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ADAPTATION CARDS
MOUTH/FEEDING
Sucker shaped mouth
EXAMPLES:
Sturgeon
MOUTH/FEEDING
Mouth on bottom of head
(inferior)
EXAMPLE:
Smallmouth buffalo
Can suck up plants, animals, or decaying organic
matter from the bottom of a lake or stream.
MOUTH/FEEDING
EXAMPLES:
Very large mouth
Walleye
Feeds on prey it looks down on, like aquatic insects and
crustaceans found at the bottom of the water column
Can swallow large prey (like other fishes)
MOUTH/FEEDING
EXAMPLES:
Upward tilted (superior) mouth
Bluegill, Crappie
Can swim fast through open water
BODY SHAPE
EXAMPLE:
Flat bellied
Flathead catfish
Can feed on prey (like
surface.
MOUTH/FEEDING
Long, toothed jaws
Helps to grasp prey firmly.
BODY SHAPE
Torpedo shaped
EXAMPLE:
Northern Pike
insects) near the water’s
EXAMPLES:
Shortnose Gar
Can lie motionless on the bottom
BODY SHAPE
EXAMPLE:
Flattened vertically
Redear sunfish
‘disc shaped’
Can maneuver easily through vegetation, rocks or
submerged trees
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BODY SHAPE
Large, spiny fins
EXAMPLE:
Pumpkinseed
COLORATION
Vertical stripes
EXAMPLE:
Northern plains
Killifish
Makes fish seem larger and more difficult for
predators to eat.
BODY SHAPE
EXAMPLE:
Humpbacked
Blue sucker
Allows fish to hide in vegetation
COLORATION
Mottled colors
Helps fish stay stable in flowing water
COLORATION
EXAMPLE:
Light-colored belly
Largemouth bass
Helps fish hide in rocks or on the bottom
COLORATION
EXAMPLE:
Silvery color
Gizzard shad
Camouflages with sunlight so that it is difficult to see
from below
COLORATION
EXAMPLE:
Dark colored on top
Rainbow trout
Camouflages with bottom so that it is difficult to see
from above
EXAMPLE:
Brown bullhead
Helps fish camouflage in open water.
REPRODUCTION
EXAMPLE:
Buries eggs in gravel at
Brook trout
bottom of stream
Hides eggs from predators, keeps oxygenated
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REPRODUCTION
Lays eggs in cavities,
like under logs
Hides eggs from predators
REPRODUCTION
Attaches eggs to vegetation
EXAMPLE:
Channel catfish
REPRODUCTION
Creates and guards nests
EXAMPLE:
Black crappie
EXAMPLE:
Yellow perch
Keeps eggs safe from predators
REPRODUCTION
Livebearer,
Doesn’t lay eggs
EXAMPLE:
Western
mosquitofish
Keeps eggs stable and oxygenated until they hatch
Increases survival rates
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Fish Anatomy: Gyotaku
Standards:
Duration: 30-45 minutes
Materials: Fish of Nebraska books
& gyotaku kit (available from
Aksarben Aquarium: includes fish
replicas, tempera paint, paint
rollers, newsprint), newspaper or
plastic to protect work area, paper
towels, crayons or colored pencils,
disposable plates for dispensing and
rolling paint.
Objectives: Students will simulate
an art form established by Japanese
fishermen centuries ago and
illustrate the coloration of fish
according to real life characteristics.
Background: Gyotaku (pronounced ghee-oh-tahkoo) literally translates to ‘fish rubbing’ and dates
back to the early 1800s. Fisherman in Japan began
this tradition to record their catch. Gyotaku allowed
them to document the size and types of fish caught
while still enabling them to sell or eat the fish. Also,
certain fish in Japan are revered, and fishermen
would take rubbings of these fish and then place
them back in the water. Prints were brought back
and displayed in the homes of the fishermen either
on walls or in journals. These prints were used as
conversation pieces and to relate proud and heroic
stories of the catch. Today we have taxidermy and
cameras to record our catches. However, gyotaku is
still practiced and has developed into a fine art form.
Preparation: Prepare the work area by covering it
with newspaper or plastic. Put a small amount of
paint into several plates. Divide students into small
groups, and distribute a fish replica , paint tray and
roller to each group.
Warm up: Have the students ever heard of “fish tales”? Fishermen are known to tell
exaggerated tales of the “huge” fish they caught. In Japan, fishermen recorded the actual size
of the fish they caught (long before cameras) with the art known as gyotaku. Explain that
gyotaku literally translates to “fish rubbing” and that, although it isn’t necessary now (because
of cameras and taxidermy), it is still a very popular art form. You may want to show examples of
gyotaku prints made by professional artists. A Google Images search of “gyotaku” will provide
many examples.
Activity:
1. LIGHTLY coat the paint roller in tempera paint – students may even want to roll out some of
the excess paint onto the newspaper before applying to the fish replicas.
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2. LIGHTLY cover the fish replica with paint using the roller. A thin layer of paint works best to
show the details of the scales and fins.
3. Place the newsprint on top of the fish. Without shifting the paper, GENTLY rub with finger
tips over the entire form, making sure to find all the edges, and all fins.
4. Carefully peel the paper off the replica and set aside for several minutes to let the paint dry.
5. OPTION: Groups can switch fish until everyone gets a print of each type of fish.
6. Using the Fish of Nebraska book, have students locate their fish and using crayons or
colored pencils color in the life colors of their fish.
Wrap up: Review the anatomy of the fish by labeling fins and other external features.
*Thoroughly rinse paint rollers and fish replicas and lay out to dry.*
Extension:
1. Have students select one of their fish and illustrate a habitat that that they think
would be suitable.
2. Make fish prints on t-shirts using acrylic paint.
3. Make fish prints using real fish. Partially frozen fish work well. Pat the fish dry, and
use table salt to help remove slime.
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Fish Anatomy: Protective Coloration
Standards:
Duration: 30-45 minutes
Materials: Copies of the fish
silhouette cutout (pg. 84), a variety
of wrapping paper or colorful
magazine pages, scissors, drawing
or decorating materials (paints,
crayons, pencils, yarns, colored
tissue papers, beads, glue)
Objectives: Students will illustrate
the importance of camouflage in the
survival of a fish by decorating fish
to match a given habitat.
Background: As the animals on earth evolved,
most developed body colors and markings that
improve their chances of survival. This adaptive
mechanism, known as protective coloration, varies
from species to species. There are a few types of
protective coloration – cryptic coloration
(camouflage), disruptive coloration, aposematic
(warning) coloration, and mimicry. The most widely
known coloration is camouflage.
When an animal is camouflaged its colors are very
similar to that of its habitat, helping to conceal the
animal either from its predators or prey. For
example, a rainbow trout’s dark spots on the dorsal
side of the body help camouflage it against the rocky
bottoms of streams.
Although protective coloration is not infallible, it does increase chances for survival of the
species. The most widely accepted explanation of protective coloration is Darwin’s theory of
natural selection – those species with a protective coloration are more likely to reproduce,
allowing their genes to pass on.
Preparation: Cut out squares of wrapping paper or a magazine page for the students to use
as fish habitat. Copy enough fish silhouettes for each student.
Warm up: Ask students to define camouflage. Camouflage is protective coloring that helps to
hide an animal. Have students give examples of animals that are camouflaged. If two of those
species mentioned above swapped habitats, would they still be camouflaged? Probably not.
Camouflage is usually specific to the animal’s habitat.
Activity:
1. Each student gets a piece of wrapping paper or a magazine page that will represent the
habitat their fish lives in.
2. Have students cut out their fish silhouette and decorate it to blend into the habitat.
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Wrap up: Review: what is camouflage and why is it helpful? Camouflage a type of coloration,
blending the animal into its own habitat. It helps hides the animal from predators as well as
prey. Have the students move their fish to another habitat. Is the fish still camouflaged? Some
animals are ‘specialists’ and only are camouflaged to a very distinct environment. Some animals
are ‘generalists’ and can fit in a few different habitats. How might this affect the survival of a
species, long term? Animals that can occupy more habitats are less susceptible to extinction.
Extension: Research the story behind the light- and dark-colored peppered moths of England,
a classic example of natural selection. Population studies have shown that prior to the
Industrial Revolution of England, the vast majority of peppered moths were light-colored. These
moths were camouflaged against the light-colored trees and lichens they rested upon.
However, during the Industrial Revolution there was a shift in population sizes. The darkcolored moths began to outnumber the light-colored moths. Scientists believe the shift was due
to increased pollution that killed lichens and blackened trees with soot. The dark-colored moths
were better able to hide on the darkened trees while the light-colored moths became more
susceptible to predation.
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FISH SILHOUETTE
Name___________________________________________
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Nebraska Fish Species: Fish Finder
Standards:
Duration: 30-45 minutes
Materials: Trout anatomy
worksheets (for reference),
dichotomous key worksheets for
each student (pg. 89), Common Fish
of Nebraska guide (available from
Aksarben Aquarium), fish
illustrations (pgs. 89-107).
Background: Scientific classification is a method
by which scientists group and categorize species of
organisms. Modern classification has its roots in the
work of Carl Linnaeus, who grouped species
according to shared physical characteristics. A
hierarchal system with eight divisions is used to
classify all of the organisms on earth. From broadest
to narrowest, the levels of classification are: domain,
kingdom, phylum, class, order, family, genus, and
species.
With millions of species on our planet, scientists rely
on a type of identification key, called a dichotomous
Objectives: Students will learn how
key, to identify items in the natural world. From
to identify different Nebraska fish
reptiles to rocks, flowers to fish, the format of a
species, how to use a dichotomous
dichotomous key is always the same.
key, and review fish anatomy and
The word dichotomous originates from Greek. The
adaptations.
prefix ‘di‘ means two while the root word originates
from ‘temnein’, which means to cut. Two choices are given at each step in the form of a
couplet, eventually leading to the correct answer. For example:
1. a. Flower has 3 petals......................Go to 2
b. Flower has 4 petals......................Go to 4
2. a. Petals’ edges are smooth............Trillium
b. Petals’ edges are fringed.............Go to 3
By reading the two statements of each couplet, you progress through the key from typically
broad characteristics to narrower characteristics until only a single choice remains.
Preparation: Prior to the activity, set up fish identification stations using the numbered fish
illustrations (species information can be taped to the back of the illustrations, but should not be
referenced while keying out the species. Information can be used during discussion after the
activity.) Make copies of the dichotomous key worksheets. Divide students into groups of three
or four and give each student a dichotomous key worksheet.
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Warm up: Tell students that in addition to rainbow trout, over 100 species of fish are found in
Nebraska’s lakes, rivers, and streams. The students should be familiar with a fish’s anatomy
before beginning part two of the lesson. Review the anatomy of a fish.
Activity:
1. Give instructions on how to use a dichotomous key. Explain that each question on the key
has only one correct answer. Following the directions after each answer will lead down a
path to the next question until a fish is identified, much like a Choose Your Own Adventure
Story.
2. Each group will start at a different station.
3. Allow each group a few minutes at their station, and then rotate groups to the next station.
4. After students have gone through all ten stations, identify each species and tally results on a
blackboard. Discuss the characteristics listed with each species.
Wrap up: What fish were difficult to key? Why? What fish were easy to key? Why? Why do
the fish all look so different? As the fish have evolved, each species has developed unique
structures and body shapes suited for survival in a particular microhabitat.

Compare the mouth of the shorthead redhorse to the mouth of the northern pike. What
does this tell us about what/where it eats? (Redhorse eat from the bottom, northern pike
eat prey near the surface of the water.)

Compare the body shape of a trout to that of a redear sunfish. What clue does this offer
about the speed of the fish? (Trout are known for their speed – often necessary for survival.
Redear, like other sunfish, are adapted to maneuver in dense vegetation and cover.)

Look at the barbels on the catfish. What purpose might these serve? What might this tell us
about where it lives? (Barbels are sensors – catfish are often found in dark, murky water
where sight is impaired.)

Why would a fish like the crappie need a spiny dorsal fin? (If a predator comes up behind
the crappie to swallow it, the crappie can extend its spines to prevent the predator from
swallowing it.)
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
Are all bluegill the same color? (No, male bluegill can develop bright orange breasts when
spawning. It is believed this helps attract a mate.) This is why colors aren’t always the best
clue to identifying a species.

Encourage any other thoughts on differences/adaptations.
Extension: Students create their own dichotomous keys for five different items of their
choice. Encourage students to become creative with those items they key.
Related reading:
Animals on the Trail with Lewis and Clark by Dorothy Hinshaw Patent
Carl Linneaus: Father of Classification by Margaret Jean Anderson
The Tree of Life by Peter Sis
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FISH OF NEBRASKA DICHOTOMOUS KEY WORKSHEET
1.
Name______________________________
a. The fish has an adipose fin…………………………………………………………………………..…..Go to 2
b. The fish does not have an adipose fin………………………………………………………….…..Go to 3
2.
a. The fish has barbels………………………………………………………………….………….…….….…Go to 4
b. The fish does not have barbels………………………………………………..…Rainbow Trout_____
3.
a. The fish has one dorsal fin (can have two parts that are connected
together)…………………………………………………………………………………………………..…….Go to 5
b. The fish has two separate dorsal fins (adipose fin is not a dorsal fin)………..…….Go to 6
4.
a. The fish has a forked tail fin…………………..……………………………………Channel Catfish____
b. The fish has a rounded tail fin……………………………………………………...Black Bullhead____
5.
a. The dorsal fin has sharp spines………………………………………………………………….……..Go to 7
b. The dorsal fin does not have sharp spines……………………………………………….……….Go to 8
6.
a. The fish has vertical stripes on its sides…………………………………………..Yellow Perch____
b. The fish has a long horizontal stripe on its side….………………………Brook Silverside____
7.
a. The fish has dark spots all over its body and fins………………………….…Black Crappie____
b. The fish has stripes on its sides ……………………….……………………………………………...Go to 9
8.
a. The dorsal fin is near the back of the fish’s body, above the anal
fin………………………………………………………………………………………………...Northern Pike____
b. The dorsal fin is near the center of the fish’s body, in front of the anal
fin…………..…………………………………………………………………………..Shorthead Redhorse____
9.
a. The fish has a large mouth that reaches back to its eye……………Smallmouth Bass____
b. The fish has a small mouth that is in front of its eye…………………...Redear Sunfish____
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SPECIES # 1
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SPECIES # 1
Black Bullhead
A chubby, scaleless fish having an adipose fin, 8 barbels (those under mouth black in color) that are used to locate food, and a
slight notch on the rear margin of the tail. Many anglers have the misconception that the whiskers (barbels) can sting them. What
have to be avoided are the hard spines (one in the dorsal fin and one in each pectoral fin) that can inflict a puncture wound if the
fish is mishandled. Bullheads will overpopulate and compete with other fish if predators are lacking. When it becomes
overpopulated, its bottom feeding activity stirs up bottom sediments - making the water muddy. Primarily feeds on immature
aquatic insects, small crustaceans, plant material and an occasional small fish. Often caught by anglers. Tolerant of turbid, low
oxygen waters and abundant in many habitats. Parental care of nests – males and females ward off egg predators and fan the
nests to aerate the eggs. Fry will school and remain under parental care until about an inch long. Will school through the first
summer. Comparatively short lived catfish species – seldom over 10 years. NE state record 3 lbs. 15 oz.
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SPECIES # 2
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SPECIES # 2
Black Crappie
Silvery fish with irregularly arranged black speckles and blotches on sides and 7 or 8 spines in dorsal fin. Spawning males become
almost entirely black. They are less tolerant of turbidity and siltation than white crappie. Aquatic insects and large zooplankton
compose a larger portion of diet of black crappie than white crappie. They usually are heavier at any given length than white
crappie. They can become overpopulated if predator populations are low. Crappies (black and white) are one of the top 5
commonly sought-after sport fish. Like other sunfish, are nest builders. Crappie have high reproductive potential, often leads to
overpopulation and stunted populations. Fry remain attached to the nest for several days after hatch. Males aggressively defend
nests. Black crappie prefer clear, quiet water. Aggregrate in loose schools. NE state record 4 lb. 8 oz.
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SPECIES # 3
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SPECIES # 3
Brook Silverside
A silvery, pencil-thin fish having a pointed, beak-like snout with an oblique, upward turned mouth; a long, sickle-shaped anal fin; 2
widely separated dorsal fins; and a long, bright, silvery stripe lengthwise along each side. It is a non-native species that was
inadvertently stocked when threadfin shad (another non-native species) were brought into the state for experimental prey
stockings for open-water predators during the late 1970's. It is adapted for life near the surface where it feeds primarily on insects
(aquatic and terrestrial) and microcrustaceans (small zooplankton).
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SPECIES # 4
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SPECIES # 4
Channel Catfish
An olive-brown or slate-blue, scaleless fish having dark spots (especially on small fish), an adipose fin, 8 barbels that are used to
locate food, and a deeply forked tail. Breeding males become dark blue and are often misidentified as a blue catfish. Many anglers
are mistaken by thinking they can be stung by the whiskers (barbels, a sensory organ). What they have to avoid are the hard
serrated spines (one in the dorsal fin and one in each pectoral fin) that can inflict a puncture wound if the fish is mishandled.
Primarily bottom-feeder, consuming living or dead items. Diet is varied and includes fish, crayfish, insects, mollusks, and plant
material. One of the top five commonly sought-after sport fish in the state. One of the most important commercially cultured
species in US. No scales. Had an adipose fin. In natural habitat, moderate to swiftly flowing streams Also abundant in reservoirs
and ponds Can tolerate turbidity (a measure of the degree to which the water loses its transparency due to the presence of
suspended particulates. Flood control reservoirs can have high turbidity due to the large watersheds that drain into them).
Primarily detect food with sense of taste, using barbels and sensory organs (like taste buds) that cover their exposed skin. Eyes are
comparatively small; channel catfish are not sight feeders. Most movement and feeding occurs after sunset and before sunrise. In
daylight, can be found in deep holes, under cover of logs and rocks. Nebraska state record is 41 lbs 8 oz
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SPECIES # 5
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SPECIES # 5
Northern Pike
Large, tubular-shaped, native fish having a single dorsal fin near the forked tail, duckbill-shaped snout, large mouth with many
sharp teeth, and 5 sensory pores on each side of the lower jaw's underside. Its cheek is fully scaled, while the gill cover is scaled
only on the upper half. It prowls vegetated areas in search of food (primarily fish) - providing an important role in regulating and
maintaining population balance of various prey fish species. Does best in natural lakes of the Sandhills. Readily caught by anglers.
Early spring spawner. Spawns in shallow water and broadcasts eggs over submerged vegetation. Rapidly growing species. Found
in sluggish streams and shallow, weedy places in lakes, as well as in cold, clear, rocky waters. Ambush predators, lie in wait and
can make a fast strike at prey. Produce an excess of slime when handled. The ancient Romans wrote about how slimy and stinky
pike are. They have free floating Y bones in their flesh that make some people dislike them as a food source. NE state record is 30
lbs.
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SPECIES # 6
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SPECIES # 6
Rainbow Trout
Non-native fish that requires cold (less than 70 degrees), well-oxygenated water. It tolerates slightly higher temperatures than
other trout. It is speckled with small black spots on sides (no orange or reddish spots), back, and tail fin which is slightly forked.
Sides also have a broad pinkish or red stripe. It also has small scales, an adipose fin on the midline of the back near the tail, and a
small, triangular-shaped axillary process at the upper end of the pelvic fin. The bulk of its diet consists of aquatic and terrestrial
insects, amphipods, crayfish, and small fish. It spawns from early winter to late spring, depending on genetic strain and availability
of clean, gravelly riffles in streams. Readily caught by anglers.
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SPECIES # 7
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SPECIES # 7
Redear Sunfish
A flat, slab-sided fish with a rather small mouth. Pectoral fin is pointed and relatively long; gill cover tab black with red margin.
They are not a native fish and do best in ponds and small reservoirs having warm, clear water with an abundance of aquatic
vegetation that harbors numerous small crustaceans and molluscs. Snails are the primary food source for redear, hence the
common name (shellcracker). Redear can be used to control snails, which are required hosts in the life cycles of yellow and black
grubs - both of which are common fish parasites. Distinguished from bluegill by larger size (in NE waters) and by the red trim on
the opercular flap. Nicknamed ‘shellcracker’ for feeding habits. Preferred habitat is in clear, quiet, warm waters with abundant
rooted vegetation. Capable of multiple spawns during summer months (65 – 80 F water temp). Can grow up to 12 inches and
weigh 2 lbs. Nebraska state record is 1 lb 10 oz
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SPECIES # 8
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SPECIES # 8
Shorthead Redhorse
A slender fish having a short, triangular-shaped dorsal fin, dark-edged scales giving the appearance of lines, and a lower lip with
grooves and a nearly straight rear margin. All fins have definite red color. Bottom-feeder, primarily consuming immature aquatic
insects. Rarely caught by anglers.
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SPECIES # 9
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SPECIES # 9
Smallmouth Bass
A torpedo-shaped fish with an upper jaw reaching about to rear margin of eye and dorsal fin is continuous with a shallow notch.
Typically bronze-colored and sides plain or with several separate vertical bars with lower sides generally without dark spots. Has
little tolerance for siltation and turbidity and thrives in streams with rock or gravel bottoms and riffles. Young primarily eat aquatic
insects and their larvae along with small fish. Crayfish are an important food item for adults as well as fish. Distinguished from
largemouth bass by a smaller mouth (does not extend past the back of the eye) and lack of a horizontal stripe (has vertical bars
instead). Males will guard nest and fry. NE state record is 7 lb. 4 oz.
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SPECIES #10
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SPECIES #10
Yellow Perch
Somewhat tubular, slab-sided fish having 2 separate dorsal fins, regularly spaced vertical bands on body, and no visible teeth. A
schooling fish that does best in shallow, well-vegetated lakes in the Sandhills region of the state, but can become stunted if
predation is insufficient. During the spawning process, females release eggs in long gelatinous strings, which are fertilized by
several males. Egg masses then become attached to underwater cover (emergent plant stems, blown-in tumbleweeds, etc.). Small
crustaceans, insects, and fish make up the bulk of the diet. NE state record 2 lbs. 11 oz.
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Nebraska Fish Species: Additional Activity
Aquatic WILD Curriculum
Fishy Who’s Who, pg. 9
Objectives: Students will forms of microscopic life that live in water and describe
how various aquatic organisms are interrelated.
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Summary and Review: Fish Bowl Trivia
Adapted from the MinnAqua Fishing: Get in the Habitat! Leaders Guide copyright by the
Minnesota Department of Natural Resources.
Warm up: Tell the students they will be playing a
Standards:
Duration: 30-45 minutes
Materials: Note cards, 10 for each
group of 4 – 6 students, pens, tape,
whiteboard and markers, coin,
noisemakers or buzzers for each
group (optional)
game of trivia that is similar to Jeopardy and that it’s
their job to come up with questions for the game. As
a group, come up with five or six categories for your
game, such as fish anatomy, habitat, water quality,
life cycles, or food webs. Across the top of the
whiteboard, write the categories as headings for
columns.
Activity:
Objectives: Students will write
comprehensive quiz questions
covering what they have learned
about trout, trout habitat, and fish
in general. Students will answer the
questions in a game of trivia.
Setting up the game:
1.
Divide the class into groups of 4 – 6 students.
Hand out note cards and pens. Ask each group to
come up with a group name. On scratch paper, have
each group write one or more questions with answers
for each of the categories, drawing from material
they’ve learned in class. Ask them to assign each
question a point value of 10, 20, 30, or 40 points depending on the difficulty of the question.
2.
Encourage the students to think through the questions they write so they are clear and
understandable. Show them a good example and a poor example of a question. Suppose that
the category heading is Fish Anatomy. An example of a good question: Which body part does a
fish use to collect oxygen from the water? Answer: Gills. An example of a poor question: How
does a fish breathe? This question doesn’t clearly ask the students to name the body part. The
actual answer to the question is open-ended and the different answers could vary significantly.
3.
Once questions and answers are completed, ask students to copy them to the note
cards like this:
Front of card: category and point value
Back of card: Question and answer
Fish Anatomy
30 Points
Q: What body part do fish
use to draw oxygen from
the water?
A: Gills
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4.
Collect each group’s note cards containing the questions and discard any duplicates.
5.
On the whiteboard, tape each question with its point value facing the class under its
appropriate category.
6.
Record each group’s name on the white board to tally points as they are accrued.
Playing the Game:
1.
Choose a team to pick the first category and point value. Remove the question from the
board and read it to the class.
2.
The first team to raise their hands or sound their noisemaker gets a shot at answering
the question.
3.
If the question is answered incorrectly the floor is open to the other teams to answer
the question.
4.
Tape the card under the winning team’s name.
5.
When all questions have been answered, have the students total the scores for each
team. You may wish to prepare a few tie breaker questions in advance of the game to
settle a tie.
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Let’s Go Fishing!
Adapted in part from the MinnAqua Fishing: Get in the Habitat! Leaders Guide copyright by the
Minnesota Department of Natural Resources.
Background: People have fished for thousands of
Standards:
Duration: Part I – 30 minutes
Part II – 45 minutes
Part III – 1.5 to 2 hours
Materials: Fishing kit available
from Aksarben Aquarium
(includes nylon rope, large dull
point hooks, knot tying cards,
casting rods, casting plugs,
casting targets, fishing line,
hooks, bobbers, weights.),
scissors or nail clippers, masking
tape.
Objectives: Students will
understand reasons why people
fish, demonstrate how to tie a
fishing knot, demonstrate how to
cast a closed-faced spinning rod
and reel, demonstrate how to set
up a fishing line with a bobber,
sinker, weight, and hook, and
understand common fishing
regulations.
years, initially for food and more recently for
recreation. Fishing is a lifelong sport that can be
enjoyed at any age.
Recent research has shown the importance of
spending relatively unstructured time in nature,
especially for children with behavioral or emotional
disorders (please read Last Child in the Woods by
Richard Louv for a thorough summary of this research).
Fishing may have a very positive effect on such
children.
A variety of fishing equipment exists; however, to get
started, a closed-faced spinning rod and reel combo,
also called a spin-casting rod, is an ideal option. This
lesson describes how to use this equipment with very
basic tackle, including a bobber, weights and a hook.
Regulations & Fishing Ethics
The NGPC is responsible for managing, conserving and
regulating the state’s resources, and that includes fish and
aquatic resources. Fishing regulations are laws about
fishing that are designed to maintain healthy fish
populations. These laws are determined in response to
economic, social, and cultural demands on the state’s
fisheries.
Anglers > 16 are required to carry a fishing permit. Money from fishing permits helps fund NGPC efforts
to manage and conserve fishing resources. ALL ANGLERS are required to follow regulations. Regulations
can include:
 Daily bag limits: A bag limit establishes the number of a particular species or group of species
that you can keep in any one day
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
Possession limits: A possession limit establishes total number of a species or combination of
species that you may possess (not just in your cooler at the lake, but also in your freezer back at
home)
 Length limits: A length limit establishes a maximum or minimum length at which a fish can be
harvested.
 Invasive species regulations. These regulations may prohibit:
- The transport of fish from one body of water to another
- The transport of water from one body of water to another
- The use of live bait fish
 Catch-and-release: This regulation prohibits any harvest of a species.
 Equipment regulations: These regulations establish and limit the types of equipment that can
be used to capture fish.
Harvesting short, too many fish, or catch-and-release fish is called poaching and is a violation of the law,
punishable by fines or even imprisonment.
Regulations shouldn’t be viewed as a restriction or a hassle or something that gets in the way of fishing –
they are actually protecting the angler’s ability to go fishing.
Fishing regulations - why have them?
 To protect resources
o Example: A statewide bag limit of 15 panfish prevents populations from being
overfished and depleted
o Example: A no live bait regulation protects a water body from the accidental
introduction of a nuisance species like carp. If carp are present, they can degrade water
quality and limit resources to sport fish
o Example: Water and aquatic vegetation cannot be transported from one water body to
another. Boats and equipment must be cleaned after leaving a water body. This
regulation prevents the spread of invasive species like zebra mussels that can consume
important food resources necessary for the survival of juvenile fish.
o Example: It is illegal to possess a threatened or endangered species.
 To distribute the catch
o Example: A possession limit of 20 channel catfish prevents an angler from keeping more
than his/her share, and protects populations so that there is fishing opportunity for all
anglers.
o Example: Anglers are limited to two lines with a maximum of two hooks on each line
when fishing in ponds, lakes and reservoirs in Nebraska. This regulation provides fair
opportunities for all anglers alike to capture fish, and helps to prevent overfishing.
 To maximize reproduction
o Example: A slot limit prevents an angler from keeping a walleye between 20 – 28 inches
at Sherman Reservoir in the Sandhills region. This regulation ensures that reproductive
female walleye will remain in the population so the walleye fishery at the reservoir is
sustainable.
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
Angler safety
o Example: equipment requirements such as life jackets, oars, and bailing buckets when
fishing from a boat protect anglers in the event of a mishap.
What is the difference between regulations and ethics? Regulations are the laws. Ethics are the moral
code that all anglers should follow.
An Angler’s Code of Ethics:
 Always practice safe fishing.
- Cast carefully.
- Handle hooks mindfully.
- Wear a life jacket when on a boat or in the water.
 Always be courteous and respectful of other people.
- Respect property.
- Clean up any litter you bring with you.
- Give other angler’s their personal space while fishing.
 Obey fishing laws.
- Have a permit when required.
- Know the regulations for the body of water where you are fishing.
 Respect the outdoors.
- Observe but do not disturb wildlife.
- Release fish right away if not planning to eat them.
- Pick up trash, even if you did not leave it.
- Recycle used fishing line and bait containers.
 Invite friends to fish with you and help them learn.
Warm up (Part I): Ask your students to raise their hand if they have been ever been fishing
before. What skills are needed in order to go fishing? Knot tying is one important fishing skill. Tell
your students that they are going to learn the improved clinch knot, and that a good knot essential
for securing the hook on the fishing line to catch fish. A bad knot will slip out or break when tension
is applied to the line, but a good knot will hold a fish that is as heavy as the fishing line is tested to
handle.
Activity (Part I):
1. Divide students into groups of two.
2. Give each student a knot tying card to use as a guide.
3. Give a piece of nylon string and large hook to each pair of students. Because it is thicker
than fishing line, string is easier to manipulate while learning knots.
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4. As a class, proceed through each step of tying the knot. Students may tie the knot to a leg of
their desk, or, if working in pairs, one student can be the “fishing pole” and hold the string
while the other student ties the knot.
HOW TO TIE AN IMPROVED CLINCH KNOT:
- Thread one end of the line (the tag end) through the eye of the hook. Make sure to
pull plenty of line through to complete the knot. Excess line can be clipped off when
the knot is tied. The other end of the line will be assumed attached to the fishing
pole.
- Wrap the line around itself 5-7 times (when using the nylon rope, 3 times is plenty).
Tip: holding the hook in one hand and both ends of the line in the other, twist the
hook to create twist in the line.
- Take the tag end of the line and put it through the gap between the first twist and
the eye of the hook.
- Notice the new loop that was created, and pass the tag end of the line back through
that new loop.
- Release the tag end and slide the knot down to the eye of the hook.
- Tug on the tag end to tighten the knot.
- Neaten the knot so that the coils are lined up with no loose wraps that may snag and
break.
Courtesy of Minnaqua
5. When the students are successful at tying the knot with the string, pass out the hooks and
fishing line. Point out the barb of the hook. Remind students that hooks are sharp; they
must be careful. It can be helpful to cover the point of the hook in masking tape. Explain
that their fishing line is made from monofilament, a thin strand of nylon.
6. Have each student tie an improved clinch knot. Tip: The monofilament should be lubricated
with saliva or water before sliding the knot down to the eye of the hook to tighten.
7. Have students cut off any excess line on the tag end close to the eye of the hook.
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Preparation (Part II): Choose a casting location, such as the gym or an open field, with few
obstacles on which to become tangled. Avoid trees. Set up the casting targets at variable
distances from where the students will cast (15-30 feet is appropriate). Assemble casting rods
and tie on casting plugs. OPTION: Have students review their knot tying skills and tie on their
own knots.
Warm up (Part II): For those students that have been fishing before, do they know what
type of rod and reel they used? Remind them that there are many different kinds of rods and
reels, and today they will be learning to cast a closed-face spinning rod which may work
differently than what they’ve used before.
Activity (Part II):
1. Go over the main parts of a rod and reel combo: rod, line guides, closed-faced reel.
2. Give each or group of students a casting rod (15 rods will be supplied with a kit).
3. Demonstrate how the reel works. Hold the grip in your hand with the reel on top. Using the
same hand that holds the reel, push the button with your thumb and hold it in. Notice that
nothing happens. Now release your thumb and watch how the line comes out and the
casting plug drops. Pull some line out of the reel and notice how it keeps coming. Turn the
reel handle forward and listen for a click. Now try to pull more line out. It shouldn’t come
out. Reel in the line.
4. Demonstrate an overhead cast. Hold the button in with your thumb. The rod should be
straight in front of you. Make sure the line is not wrapped around the tip of the rod. Look
over your shoulder to make sure no one is standing behind you when you cast; look
overhead and behind you for any obstructions, such as power lines or tree branches.
Keeping your elbow at your side, bend your elbow to bring the rod tip back so that it points
straight up as you watch it. Then bring the rod tip forward and release your thumb as you
bring the rod forward. Stress that it is important to point the rod tip in the direction you
want the casting plug to go. Watch as the casting plug takes the line straight out in front of
you. If students raise their elbows and bring the rod behind the shoulder like they are
preparing to throw a baseball, have them place a book between their elbows and the side
body to keep the arm in position while they cast.
5. Allow the students to practice casting to the targets.
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Warm up (Part III): Ask your students if they know what the word “steward” means. A
steward is someone who takes action to protect the environment. Tell the students that one of
the most important traits an angler can possess is being a good steward. Ask your students how
they can be good stewards while fishing?
Some examples include: Read and follow the regulations (regulation guides are available from
the Aksarben Aquarium), do not litter (this includes fishing hooks, line and bait!), practice catch
and release fishing when you do not plan to eat your catch, learn how to identify the fish that
you catch, do not release aquarium fish into the wild.
Discuss the important of following regulations. Discuss the difference between fishing
regulations and fishing ethics.
Activity (Part III): Contact your TIC coordinator to schedule a fishing trip! Fishing trips can
also be scheduled to coincide with your trout release at the Schramm Park in Gretna.
Wrap up (Part III): Did any students catch fish? What types of fish were caught? Where were
fish caught? Where weren’t fish caught?
Extension:
Have students research one species of fish they caught. What does that species eat?
What is its preferred habitat? What preys upon it?
Related reading:
A River Dream by Allen Say
Fly-fishing with Trout-tail: A Child’s Journey by Kimberly H. Lucas
Hook a Fish, Catch a Mountain by Jean Craighead George
Kids’ Incredible Fishing Stories by Shawn Morey
The Barefoot Fisherman: A Fishing Book for Kids by Paul Amdahl
The Case of the Missing Cutthroats by Jean Craighead George
Casting a closed face rod and reel combo by Minnaqua
http://files.dnr.state.mn.us/education_safety/education/minnaqua/leadersguide/chapter_5/5_
2_casting_a_closed_face_rod_and_reel.pdf
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Nebraska Trout in the Classroom Order Form
Available online at fishingnebraska.wordpress.com
Remit to [email protected] or fax to 402 332-5853
PLEASE ALLOW AT LEAST TWO WEEKS LEAD TIME FOR EQUIPMENT AND MATERIALS REQUESTS.
LOANED EQUIPMENT MUST BE RETURNED WITHIN 1 WEEK OF RECEIPT.
Instructor:_________________________________________________________________________________
School name:_______________________________________________________________________________
Date needed:____________________________**Pick-up date______________________________________
**Address where materials should be sent:______________________________________________________
______________________________________________________
Telephone:___________________
______________________________________________________
Email address:_____________________________________________________________________________
Reserved Equipment (available on a limited basis)
________Fishing kit (15 rods and reels , 5 Backyard Bass, 25 casting plugs, 10 oversized hooks, 10 lengths nylon rope,
monofilament fishing line, Aberdeen hooks)
_________Fish printing kit (3 rubber molds, 2 paint rollers, black tempera paint, newsprint)
________Macroinvertebrate collection kit (collection trays, tweezers, pipettes, nets, magnifying glasses, laminated
identification sheets, preserved samples – available for local pick up only.)
_________Trout dissecting kit (scissors, scalpels, tweezers, magnifying glasses)
OFFICE USE ONLY
Handout Materials (indicate quantity needed)
______Bobbers
Date To Ship ______________
_____Knot tying cards
_____NE fishing regulation booklet
Call Tag
_______________
_____Fish ID booklet
______Fish of Nebraska bookmarks
**IF YOU ARE LOCATED WITHIN 50 MILES OF THE AKSARBEN AQUARIUM, PLEASE ARRANGE TO PICK YOUR
EQUIPMENT UP IN PERSON.