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The Great Oyster Debate

Activity Summary

Students will consolidate their learning, examine other perspectives, 

and demonstrate their mastery of ecological principles. They realize 

there are conflicting interests, but that science can be helpful in 

navigating the complexity of biological and sociological interactions.

Learning Objectives

Student will be able to:

• Integrate learning and demonstrate understanding of current 

ecological issues.

• Argue an issue based on scientific principles and not belief.

• Apply scientific knowledge to social and economic issues.

Essential Question

Would the health of the Chesapeake Bay improve if the Asian Oyster 

were introduced?

Background Information

Oysters play key roles in the estuarine environment, filtering water and 

serving as a food source. Their reefs provide habitats for other marine 

species and reduce coastal erosion. Oysters play an important role in 

the economy as well. Overharvesting, habitat destruction, water 

pollution, and disease have taken a toll on oyster populations. Many 

efforts are underway to restore the oysters. One option is to introduce

K-12 Oysters in the Chesapeake Bay

Grade Level: 

Grade 5

Teaching Time: 

45-90 minutes

Materials:

• Handouts

• Optional:

oLive Oysters

oAquarium or 

other clear-sided 

container with 

brackish water

oDirt (silt)

Teacher Note:

This activity can be used 

with a demonstration of 

how live oysters filter the 

bay.
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Asian Oysters, which seem to be resistant to MSX and Dermo, the two diseases that are considered 

the leading cause of oyster mortality.

Key Words

Dermo—a disease which kills oysters (but does not harm humans).

Estuary—An estuary is a body of water formed where freshwater from rivers and streams flows 

into the ocean, mixing with the seawater. Estuaries and the lands surrounding them are places 

of transition from land to sea, and from freshwater to saltwater. Although influenced by the 

tides, estuaries are protected from the full force of ocean waves, winds, and storms by 

the reefs, barrier islands, or fingers of land, mud, or sand that surround them.

MSX—Disease which kills oysters (but does not harm humans).

Native—Produced, living, or existing naturally in a particular region or environment.

Oyster—Bivalve mollusk with rough irregular shell sometimes eaten as a delicacy and may be 

farmed for food or pearls. Native Chesapeake Bay oysters are the species Crassostrea virginica.

Phytoplankton—Microscopic plantlike organisms in aquatic environments that produce their 

own food. Oysters eat by filtering these out of the water.

Pollution—Something that is harmful to the environment.

Activity Procedure

Introduce oysters and their role in the Chesapeake Bay environment. Depending on what 

topics you’ve covered, you may want to have students examine the environmental conditions, 

food webs involving oysters, oyster life cycle or biology. This will probably take one 45 minute 

class period.

Engagement 

1. Engage students with the “See, Think, Wonder” thinking routine, slowly revealing a full 

oyster environment photo. Start by showing a close-up picture oysters (Appendix 8), 

asking what kids see, think, and wonder, then showing a little more of the picture 

including the reef and water, and finally, the whole picture with the bird. 

2. If desired, show students live oysters and demonstrate how they can clean a tank full of 

murky water. If live oysters are not available, you can show the video listed in the Web 

Resources section at the end of the lesson.

Exploration

1. Using the resources in Appendices 1-7, students should explore information about 

native oysters. Use the Student Handout (Background Information) to help guide and 

extend their thinking about the challenges to oyster populations.
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2. Set up a class-wide debate over the proposed introduction of the Asian oyster into the 

Chesapeake Bay. The preparation phase will take ~25 minutes and the debate will take 

~20 minutes. See the Explanation section for more detailed information about forming 

groups, debate roles, alternative formats, and debate preparation.

3. Divide students into four distinct "social perspectives" -- Restaurant Owner, Waterman, 

Environmentalist, and Scientist. 

4. The amount of preparation time will vary greatly (between 30 and 90 minutes) 

depending upon how the activity is structured. Preparation should include group 

discussion and use of background resources—particularly the Base Articles (in Appendix 

1 & 2 or download from Background Resources under Lesson Materials).

Explanation

1. For a class size of 20 to 24, try dividing students into groups of five or six for each of the 

four roles—Restaurant Owner, Watermen, Environmentalist, and Scientist. For larger 

classes, create two groups for each role—a class size of 32 would consist of eight groups 

of four students each. It is not critical for groups to have equal numbers of 

students...just an equal distribution of reading, analytical, communication, and 

leadership skills.

a. With respect to the four different perspectives, the Watermen role is probably 

the most straight-forward and the Environmentalist the most complex and 

nuanced. The “Teacher’s Key” at the end of the lesson outlines the basic 

positions of each perspective.

b. It is best to assign roles in a random fashion. (Perhaps pick a label or symbolic 

item from a container).

2. Start the debate by having each group explain their position and back it up with three 

evidence-based points. After each group presents (or after all groups present), the 

other groups should to respond directly to the arguments of the presenting group, not 

just state their own viewpoints.

3. The Teacher’s Key outlines the basic positions of each perspective and can be used to 

evaluate the students’ understanding.

4. At the conclusion of the debate, discuss the presentations with the class. Which 

argument was the most persuasive and why? How well did the groups do responding 

directly to the arguments and not only giving their opinions? What could the students 

do to improve their positions or the debate?

5. An alternative debate format is simply to assign each student a “Yes” or “No” position 

with respect to whether or not the Asian Oyster should be introduced into the 

Chesapeake Bay. Each individual would then develop a list of three to five reasons that 

support their assigned position.

Extension

The students can debate another topic such as the introduction of nutria, an herbivore, into the 

US. Originally imported for its fur, nutria were later sold around the country to control noxious 

weeds or set free when the fur business was no longer profitable. See Resources section for 

links to information about nutria.
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Evaluation

Formative: 

1. Student Background Handout

2. Student Debate Preparation Handout

Summative: 

1. Student Debate Notes Handout

2. Student Debate
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Education Standards

Three Dimensional Learning

Disciplinary Core 

Idea(s)

LS2.A: Interdependent Relationships in 

Ecosystems

Organisms can survive only in 

environments in which their particular 

needs are met. A healthy ecosystem is 

one in which multiple species of 

different types are each able to meet 

their needs in a relatively stable web of 

life. Newly introduced species can 

damage the balance of an ecosystem.

(5-LS2-1)

How Standard is Addressed

Students are learning and 

applying their knowledge of 

Asian oysters and their 

effects on the ecosystem as 

develop a fact-based 

argument.

Science/Engineering 

Practice

Engaging in Argument from Evidence

Support an argument with evidence, 

data, or a model. (5-LS2-1)

Students support their 

position on the introduction 

of the Asian oyster with 

evidence from their research.

Cross – Cutting 

Concepts

Systems and System Models

A system can be described in terms of 

its components and their interactions. 

(5-LS2-1))

Students learn about the 

interactions of the Asian 

oyster and how the 

ecosystem into which they 

are introduced is affected. 

Common Core Standards

Ties to Common 

Core

LA - RI.5.7: 

Draw on information from multiple print 

or digital sources, demonstrating the 

ability to locate an answer to a question 

quickly or to solve a problem efficiently.

Students use various print 

and digital resources when 

gathering facts to support 

their debate position.

Maryland Environmental Literacy Standards

Ties to MD 

Environmental 

Literacy Standards

STANDARD 1 ENVIRONMENTAL ISSUES

Indicator 3: Given a specific issue, 

communicate the issue, the 

stakeholders involved and the 

stakeholders’ beliefs and values.

Students research 

stakeholder groups and use 

facts about Asian oysters to 

develop stakeholder beliefs.
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Resources

Background Articles:

Oysters in the Chesapeake overview at

http://www.chesapeakebay.net/fieldguide/critter/eastern_oyster

A good summary of the habitat and biology of the Eastern Oyster from South Carolina 

Department of Natural Resources. Available at:

http://score.dnr.sc.gov/deep.php?subject=2&topic=15

“CBF Oysters: Great shellfish of the Bay” (Chesapeake Bay Foundation). Web site available at: 

http://www.cbf.org/about-the-bay/more-than-just-the-bay/creatures-of-thechesapeake/eastern-oyster

Debate Base Articles

“Oyster Restoration in Chesapeake Bay” (U.S. Fish & Wildlife Service— Chesapeake Bay Field 

Office). Appendix 1 or available online as a pdf at: 

http://cift.pair.com/shasta/~Potomac/comcentr/pubforum/pdfs/AsianOyster.pdf

“Non-Native Oysters and the Chesapeake Bay.” (Chesapeake Bay Program). Appendix 2 or web 

site available at: http://www.chesapeakebay.net/content/publications/cbp_12233.pdf

Supplementary Articles:

“Foreign Oysters Not a Quick Fix for Chesapeake Bay, But Aquaculture of Sterile Oysters May 

Help.”(The National Academies Press Release, August 14, 2003). Available at:

http://www8.nationalacademies.org/onpinews/newsitem.aspx?recordid=10796

Fahrenthold, David A. “Oyster Decision Could Alter the Bay.” The Washington Post, 15 February, 

2009. Available at: http://www.washingtonpost.com/wpdyn/content/article/2009/02/14/AR2009021401759.html

Additional Resources:

TeacherTube video on oysters filtering water: http://www.teachertube.com/video/oystersfiltering-water-time-lapse-211324

YouTube video on oyster restoration: http://www.youtube.com/watch?v=iSjkQsH-QsQ

Government ruling on introducing Asian oysters , (Chesapeake Bay Foundation) April 1, 2009. 

http://www.chesapeakebay.net/blog/post/officials rule against introducing asian oysters 

into bay

For more information about oyster biology see: http://www.mdsg.umd.edu/lessonplans/oyster-behavior-larval-stage

Resources about Nutria
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Chesapeake Bay Program Nutria Page: http://www.chesapeakebay.net/fieldguide/critter/nutria

Maryland DNR site about Nutria: 

http://dnr2.maryland.gov/wildlife/Pages/plants_wildlife/Nutria.aspx

Aquatic Invasive Species – A Maryland Sea Grant Brief: 

http://www.mdsg.umd.edu/sites/default/files/files/Nutria_AIS%20brief_PI-2013-02.pdf

USGS Patuxent Wildlife Research Center Fact Sheet:

https://www.pwrc.usgs.gov/FACTSHTS/FACT1.PDF

Chesapeake Bay Nutria Eradication Project FAQs: 

http://www.fws.gov/chesapeakenutriaproject/FAQs.html
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Teacher Key—The Great Oyster Debate: 

Seafood Restaurant Owner: YES... introduce the Asian Oyster 

(C. ariakensis)

 The taste of the Asian Oyster is very similar to the Easter Oyster and it returns a 

traditionally-important food item to local menus.

 It will increase the supply and decrease the cost of oysters.

 It will improve the local economy.

 It will repair oyster reefs and increase the biodiversity of the Bay.

Watermen: YES... introduce the Asian Oyster as quickly as possible.

 The Asian Oyster grows much faster and larger than the Eastern Oyster

 It is resistant to local diseases (Dermo and MSX).

 It will save the oyster industry and local jobs.

 It will increase oyster populations and improve the health of the Bay.

Environmentalist: YES or NO depending upon the reason and perspective.

 Oysters are a “keystone species” and restoring the population would restore the 

ecological balance of the Chesapeake Bay ecosystem.

 The U.S. Fish and Wildlife Service is mandated by Federal Law—the National 

Invasive Species Act of 1996—to prevent and control non-native species.

 Introduction of the Asian Oyster would quickly improve ‘filtering capacity’ and thus 

greatly improve the Bay’s water quality.

 Current efforts at reseeding and rebuilding native oyster reefs (C. virginica) are not 

yet complete—more time is needed to evaluate the success of these restoration efforts.

 Local jurisdictions have not adequately implemented nor evaluated the effect of 

harvest moratoriums on the recovery of Eastern Oyster populations.

 Even if there were no downside to introducing the Asian Oyster, it would take more 

than 20 years for populations to expand enough to have a positive impact.
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Scientist: NO... don’t introduce the Asian Oyster into the Chesapeake Bay.

 There is not enough scientific information to make an informed decision—at least 5 

years more years of research is needed.

 Past experience has shown that the introduction of non-native species is almost 

always highly disruptive to the local ecosystem.

 Preliminary observations suggests that C. ariakensis may not build reefs in the same 

way C. virginica does and therefore its “ecological value” may be somewhat limited.

 The Asian Oyster might spread beyond the Chesapeake Bay and impact healthy local 

oyster populations along the East Coast.

 Introducing the Asian Oyster could introduce new diseases which might affect other 

organisms like the Blue Crab. (It is thought the diseases Dermo and MSX entered the 

Bay when various efforts were made to introduce the Pacific Oyster (C. gigas) into the 

Chesapeake in the 1930’s).

 The Asian Oyster could out-compete the Eastern Oyster for food and living space and 

drive it to extinction. (This would prevent the local oyster from evolving a natural 

defense to the disease parasites).
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Student Handout (Background Information)

Name: ______________________________ Date: _____________ Period: _______

Oyster Background Information

What is an oyster’s environment?

What is oysters’ role in a food web?

What impact do oysters and oyster reefs have on wildlife?

What impact do oyster reefs have on the shoreline?

What impact do oysters have on the economy?

What problems affect oyster populations?

What ideas do you have about how to increase oyster populations?
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Student Handout (Debate Preparation)

Name: ______________________________ Date: _____________ Period: _______

Should the Asian Oyster (C. ariakensis) be introduced into the Chesapeake 

Bay ecosystem?

Directions: Your team will be assigned one of the social roles —Restaurant Owner, 

Watermen, Environmentalist, or Scientist. First, as a team, decide what position people 

from your perspective would most likely take (check-off one choice). Then, carefully 

discuss the issue and list four clear and distinct reasons that support this position. 

These will serve as your notes for your debate presentation.

Role: _______________________ ___ Yes ___ No ___Maybe

1.

2.

3.

4.
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Student Handout (Debate Notes)

Name: ______________________________ Date: _____________ Period: _______

Restaurant Owner (circle one) YES NO MAYBE Watermen (circle one) YES NO MAYBE

Environmentalist (circle one) YES NO MAYBE Scientist (circle one) YES NO MAYBE
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Appendix 1: Base Article #1 

http://cift.pair.com/shasta/~Potomac/comcentr/pubforum/pdfs/AsianOyster.pdf

 
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Appendix 1: Base Article #1 

http://cift.pair.com/shasta/~Potomac/comcentr/pubforum/pdfs/AsianOyster.pdf
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Appendix 2: Base article #2: http://www.chesapeakebay.net/content/publications/cbp_12233.pdf
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Appendix 2: Base article #2: http://www.chesapeakebay.net/content/publications/cbp_12233.pdf
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Appendix 3: Background Information: CBF Oysters: Great shellfish of the Bay 

http://www.cbf.org/about-the-bay/more-than-just-the-bay/creatures-of-the-chesapeake/easternoyster

Eastern Oyster

Great Shellfish of the Bay

Since colonial times, the Chesapeake (meaning "great 

shellfish Bay" in Algonquin) has lost more than 98 

percent of its oysters. Gone are the days when oyster reefs 

posed navigational hazards to Chesapeake Bay explorers 

or watermen pulled 17 million bushels of oysters each 

year. Now, Maryland and Virginia watermen and the 

seafood industry have lost $4 billion in income in the past 30 years alone. But as recent 

studies find, all is not lost.

A two-month Maryland Department of Natural Resources survey conducted in 2011 

revealed higher levels of oyster reproduction and a lower mortality rate. In fact, 

Chesapeake Bay oysters seem to be growing heartier and more robust. Given that each 

adult oyster filters and cleans up to 50 gallons of water per day—gobbling up algae, and 

removing dirt and nitrogen pollution—that's good news for the health of the Chesapeake 

Bay and for us.

After a devastating bout with disease in the late 1980s combined with decades of 

overharvesting, habitat destruction, and water pollution, the oyster was hanging on by a 

thread. "That was a turning point really," says Chesapeake Bay Foundation (CBF) 

Fisheries Director Bill Goldsborough, "because up until that point, for the previous 100 

years, oysters had supported the most valuable fishery in the Chesapeake Bay."

Now, thanks to increased awareness, extensive restoration efforts such as CBF's citizen 

oyster-gardening program and reef ball production, resisting the introduction of a nonnative oyster species, and favorable weather conditions, there is hope for the mighty 

oyster yet.

Learn more about CBF's oyster restoration efforts.
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Appendix 4: Oyster Biology & Ecology biology of the Eastern Oyster from South Carolina 

Department of Natural Resources. Available at: 

http://score.dnr.sc.gov/deep.php?subject=2&topic=15
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Appendix 5: Chesapeake Bay Oyster Reefs Available at: http://www.cbf.org/image/area---join-us/morethings-you-can-do/CBF_oyster-reefs-sign_large.png

Visit the website and explore the image to identify and learn about organisms 

commonly found in Chesapeake Bay oyster reefs.
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Appendix 6: Oyster Biology & Ecology biology of the Eastern Oyster from South Carolina 

Department of Natural Resources. Available at: 

http://score.dnr.sc.gov/deep.php?subject=2&topic=15

Life Cycle

Adult oysters begin reproduction when water temperatures become greater than 68

degrees F (~20 degrees C). In South Carolina this generally occurs from May through 

October. Oysters are broadcast spawners, meaning they release eggs and sperm into 

the water column. A fertilized egg develops into a planktonic (freeswimming) trochophore larva in about 6 hours. A fully shelled veliger larva is formed 

within 12 to 24 hours. The larva remains planktonic for about three weeks. Towards 

the end of this period it develops a foot (hence, pediveliger) and settles to the bottom 

of the water column where it seeks a hard substrate. When a suitable surface (ideally 

adult oyster shell) is located, the larva cements itself and metamorphoses to the 

adult form. This newly attached oyster is known as a "spat."
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Appendix 7: Oyster Biology & Ecology biology of the Eastern Oyster from South Carolina 

Department of Natural Resources. Available at: 

http://score.dnr.sc.gov/deep.php?subject=2&topic=15

Reef Ecology

Oysters are the building blocks of one of the most important benthic communities in 

South Carolina estuaries, the oyster reef. Formed as a result of years of oyster 

production and settlement in concentrated areas, reefs have become home to a 

complex assemblage of animals and plants. Benefits of oyster reefs to the coastal 

environment include the following:

• Providing solid structure within the water column for sessile (permanently attached 

or fixed) organisms (for example, barnacles and sea anemones)

• Providing spawning substrate for fishes (for example, gobies, blennies, and 

skilletfish)

• Stabilizing bottom sediments for benthic organisms (for example, hard clams) and 

aquatic plants

• Creating homes and hiding places for organisms seeking refuge from predation (for 

example, polychaete worms and soft-shell blue crabs)

• Concentrating prey (food) species for larger predator fishes (for example, striped 

bass)

• Serving as breakwaters to protect adjacent shorelines from erosion

• Filtration and clarification of water

Some of the information in this section is modified from Oysters in the 

Environment found at www.mdsg.umd.edu.
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Appendix 8: Eastern oyster reef with an American oystercatcher. Photo credit: Dale Glass