Objective: Students will learn all participants in the environment must agree to conserve
and preserve. Students will also learn their roles in maintaining a stable and healthy lake
and its habitants. They will be able to explore their personal conservation ethic toward
natural resources and toward fellow anglers or other outdoor recreationists.
Materials: Lake game board, 4 gold fish per game board, 12 "other" fish per game
board, shallow plastic box and lid (a 2-3" hole should be cut in the lid), plastic spoons
(one per student), laminated story cards, paper and pencils
Background: A "commons" is any resource used as though it belongs to all. In other
words, when anyone can use a shared resource (such as fish in a lake) simply because
one wants or needs to use it, then one is using a commons. A commons is destroyed
by uncontrolled use - neither intent of the user, nor ownership are important. A tragedy
occurs as the result of everyone having the fatal freedom to exploit the commons.
Garrett Hardin's essay (written in 1968) explains this phenomenon. The synopsis of the
essay is this: Visualize a pasture as a system that is open to everyone. The carrying
capacity of this pasture is 10 animals. Ten herdsmen are each grazing an animal to
fatten up for market. In other words, all the grass that the pasture can produce is now
being consumed by the 10 animals.
Harry (one of the herdsmen) will add one more animal to the pasture if he can make a
profit. He subtracts the original cost of the new animal from the expected sale price of
the fattened animal and then considers the cost of the food. Adding one more animal
will mean less food for each of the present animals, but since Harry has only 1/10 of the
herd, he has to pay only 1/10 of the cost. Harry decides to exploit the commons and the
other herdsmen, so he adds an animal and takes a profit. Shrinking profit margins force
the other herdsmen either to go out of business or continue the exploitation by adding
more animals. This process of mutual exploitation continues until overgrazing and
erosion destroy the pasture system, and all the herdsmen are driven out of business.
The critical flaw of freedom in the commons is that all participants must agree to
conserve and preserve the commons, but any one can force the destruction of the
commons, or in other words, participants must agree upon and regulate ways to limit the
uses and abuses of common resources by encouraging stewardship of those
Fisheries managers attempt to maintain fish populations near their natural carrying
capacity so that an optimum amount of fish can be harvested each year. This amount is
called "optimum sustainable yield". This rate is considered carefully for each species of
harvested fish so that overfishing will not occur and endanger the reproductive stock.
Managers regulate recreational fisheries by setting bag and size limits and establishing
seasons. This is so that there will be enough mature fish remaining to reproduce and
provide recreational fishing year after year. When a species is having difficulty
maintaining a stable populations size, regulations such as catch and release restrictions
may be imposed to aid in maintaining the "reproductive stock" (fish which have matured
to their reproductive age) and enable fish population to recover their healthy populations
size. Because fish and lakes are considered common property, the cooperation and
communication of all people enjoying and benefiting from the resource is important.
Explain to students the "tragedy of the commons". Have students brainstorm ways to
prevent the tragedy from occurring in a lake. Copy their ideas onto the chalkboard. After
everyone has shared their ideas, have class discuss the possible problems with the
ideas written on the boards. Record the problems. Then have students, either
individually or in small groups, list ways to solve the problems. Record solutions.
Place multiple fish (both goldfish and "other" fish) in the shallow box. The fish
represents a fish population in a lake. The shallow box represents a lake. Students fish
in the box by reaching into it with a spoon to "catch" their fish. Restock the fish
population randomly (remember you don't know how many fish remain in the lake).
Explain to students that this situation is similar to real-life fisheries management where
people work from estimates of fish populations. After everyone has had a chance to
"fish", ask the following questions: 1). What happens to the fish population in the lake if
people take fish too rapidly? (People get fish for themselves very quickly, but the fish
population does not have time to replenish itself, soon making the fish population
crash!); 2.) How can managers regulate uncertain fish populations for recreational
fishing? (Set a size or bag limit, set seasonal limits, institute catch and release
programs, etc. - answers will vary and many may come from the problem/solution
session that preceded Activity 1); 3.) How might fishermen contribute to the health of the
fish population? (being careful not to over-fish a specific type of fish, limit hours of
fishing, work with local management to voluntarily limit fishing, etc. - answers will again
Conduct the activity again, but use the students' knowledge gained from playing it the
first time. Did the knowledge gained while playing the original activity version result in
longer, more successful fishing? Discuss with students what happens if people take out
fish in limited numbers and the fishery has time to keep up with the harvest rate. Your
class should come to the conclusion that fish will be more available in the lake with
Separate fish from Activity 1 and place back into holding bags. It is important not to mix
up the goldfish with the "other" fish.
Divide students into groups of 3-4 students. Give each group one lake. Explain to
students that each is an angler and will be fishing in their own lake. STUDENTS ARE
NOT ALLOWED TO TALK during the activity. Each angler will harvest 1, 2 or 3 fish
during their turn. The amount and the species of fish harvested is each individual's
Provide each group 12 "other" fish and 4 goldfish. If you'd like, you can use more fish,
just be sure to keep the ratios at 4:1. With more fish the activity will take a little longer,
but the solution will not be quite as obvious. When placing the fish in the lake, try to be
circumspect when counting out the fish so that students do not connect the numbers as
being critical to the outcome of the activity.
Each round will represent one year.
At the end of each year, for every fish remaining in the lake, one new fish (of the same
species) will be added. For example, if there are 6 "other" fish and 1 goldfish left, 6
more "other fish" will be added and one more goldfish will be added to the fish stock.
However, for each new year, the total number of fish in the lake cannot exceed the
original carrying capacity of 16 fish. Anglers should keep the fish they have harvested in
front of them.
Explain that the lake is at carrying capacity. Advise anglers that each year you will stop
the activity to replenish the fish populations in each lake by doubling the number of fish
remaining in each lake (but remember to never exceed the carrying capacity). The
anglers will need to record the number of fish "caught" and the number of fish remaining
in the lake at the end of each year.
Repeat the activity for another round (year) letting each angler fish as desired. If any
group has harvested out all it's lake's fish, tell them they are done playing because the
lake's fish population has been wiped out. Replenish fish in the lake at the end of the
round, doubling only the amount remaining in each lake.
Repeat the procedure a third year. Make sure to record data at the end of each round.
Lead a class discussion using the following questions: Who caught the most fish?
Which lake provided the greatest total harvest of fish? Why? Which lake was fished out
the soonest? Why? Which species was wiped out first? Why did this happen? Why
were fish replaced only if some remained in the lake (reproduction requires parental
stock)? Why were fish only replaced to a total of 16 (carrying capacity of the lake was
maxed out - the lake is not capable of sustaining more fish)? Apply the
problem/solutions from the beginning of the activity during the class discussion.
Replay the game and have students record their fishing data at the end of each round.
Compare the first sessions' results with the second game. Discuss the differences. You
should find that once the anglers start to use a cooperative fishing strategy, each fish
population will remain healthier longer - thus eliminating the tragedy of the common.
Collect all the fish and lakes. Place fish back into appropriate bags.
Give each group a story card. Each story presents a situation that poses an ethical
problem with more than one "right" choice. Have each group consider what the central
character should do and list the obligations and responsibilities that ought to exist with
each situation. Have students write down their solutions to each situation and then have
each group share their own story, what they identified as problems and the solutions
they would apply. Note: some story cards contain a more detailed dilemma. Those
cards should be given to a group of students who are more familiar with fishing.
Invite a local angler to accompany your class on a fishing trip. Have children keep a
journal of their day at the fishing hole. Encourage the angler to tell his/her best fish
stories to the class. If any of your students have their own fish stories, have them share
with the class. After returning to the classroom, have students do a "memory-walking"
drawing of their fishing experience. Display their "fish story" drawings around the
Visit a housing facility for older citizens. Have your class relate their fishing experiences
the residents of the facility. Bring drawings or any narratives the class has put together
to share with the residents. After the visit, have your class draw "fishing" thank-you cards
and send off to the facility.
Visit a local fish hatchery.
Angler: Fisherman or fisherwoman
Carrying Capacity: The maximum amount of habitants that can be sustained in a specific
Optimum Sustainable Yield: The amount of fish that can be harvested from a specific
area during the year
Reproductive Stock: Fish which have matured to their reproductive age
Science, Reading, Social Studies,
SD Standards for 4th grade:
4.R.1.2; 4.R.3.3; 4.R.2.1
4.L.2.1; 4.L.2.2; 4.L.3.1; 4.L.1.1
4.M.1.; 4.A.3.1; 4.S.2.1; 4.A.2.2;
4.A.1.1; 4.N 3.1
Problem Solving, Critical Thinking
Prior Preparation: View the Fishes of
the Dakotas poster included in the
trunk. Lead a class discussion about
the types of fish in South Dakota.
Encourage students to relate their
fishing experiences. Next read "The
Cod's Tale" to students as an
introduction to fishing and the
problems that occur when you overfish
angler, carrying capacity, optimum
sustainable yeild, reproductive stock