Invasive Species Case Study 2:

Can Suminoe Oysters Save Chesapeake Bay: introduction of a non-native species*



“If you don’t do the right thing, we will take matters into our own hands.”


State Senator Ben Fisher hung up the phone slowly. That was one of his constituents, one of the many he had heard from that day, each one angrier than the last it seemed. His was the swing vote on the Assembly bill funding the full-scale introduction of sterile Suminoe oysters to the Maryland side of the Chesapeake Bay. The bill was an attempt to try to off-set the effects of declining populations of native oysters in the bay, the result of habitat degradation, over-harvesting, and disease. Introducing the Suminoe oysters would be an expensive and risky undertaking, but there were costs—both environmental and economic—of doing nothing, too.


Environmentalists were divided, “clean” versus “pristine.” Some demanded widespread seeding of the imported oysters to deal with worsening water quality that was wiping out aquatic life in the bay. Others warned that this could be a bigger disaster than kudzu. Test introductions in Virginia had been limited and closely monitored—and so far so good. But scientists warned that a few oysters would be fertile and might proliferate, forcing out the last of the Eastern oysters or interbreeding with the native species - bringing who knew what changes to the already damaged ecosystem?


Ben gazed out his office window. “CLEAR THE BAY!” said one of the banners that blocked his view of the sailboats in the harbor. “DON’T TINKER WITH A NATIONAL TREASURE!” warned another.


Business interests held all sorts of positions. “We’d rather see those tax dollars go into developing infrastructure for high-end development,” a major developer with plans for summer homes, condos and retail shops had emailed Ben. “Do you know what that land is worth under those broken-down, abandoned fishing shacks?” He didn’t need to add that he put a lot of money into political campaigns.


The owner of a fish market had called earlier in the day, worried that the oysters, whether native or otherwise, might not be fit for eating as a result of all the pollution they filtered from the water. She had few oysters to sell now—would the new ones appeal to customers?


The Delmarva Peninsula poultry producers didn’t want any more controls on the nutrient load entering the bay. They felt there were too many controls as it was, and warned that more controls would hamper their operations. They were all in favor of the oysters as a solution. So were the charter-boat owners who wanted clear water for the rockfish.


The commercial fishing industry wanted the oysters too, and now. Boats were idled and processing plants were handling trucked-in Louisiana oysters. The biggest plant in Ben’s district said it would close this year if things didn’t change. These new oysters grew three times as fast, they said. It wasn’t too late to save an industry.


On the other hand, the State of North Carolina was threatening a lawsuit, fearful that the nonnative oysters would spread down the coast and affect their beds. They cited the destructive virus brought in by oyster introductions decades ago.


And many of Ben’s constituents were in an uproar over the expense that Marylanders would bear for the oyster option—or the alternative. Towns and cities didn’t want to spend money to upgrade their sewer systems when so much pollution came from out-of-state.


Even within the Senator’s own family there was division. His father, who had started fishing oysters when he was a boy, said it was time to let the old ways go, that fishing was no way to make a living these days. Spend the money elsewhere. His daughter, a member of a cultural preservation group, pleaded: “We need to preserve the watermen culture. We need the oysters.”


And now this dramatic phone call—desperate people threatening to take the matter into their own hands and dump imported oysters—nonsterile ones that could reproduce and spread—into the bay to restore the beds. The debate had dragged on too long, they said. A decision had to be made.


Senator Ben Fisher left his office and walked down the echoing hall to the Assembly chamber, where he would have to cast his vote.


General: all groups have the same first four questions:

1. Compare the terms ecosystem, community, species, and population as they relate to ecology.
2. What is the difference between exponential and logistic growth? What are some density-dependent factors that keep populations from growing exponentially indefinitely? What are some density-independent factors?
3. What is an ecological niche? What happens when two species have identical niches? How does the fundamental niche differ from the realized niche?
4. Explain an example of resource partitioning, and explain how natural selection can lead to character displacement.
5. Describe an example of each of the three types of symbiosis discussed in your text.
6. Explain how energy moves through the living components of an ecosystem (starting with primary productivity and including a discussion of food webs and ecological pyramids).
7. Explain how water, carbon, and nitrogen cycle through ecosystems, and give at least one example for each of how human activities can alter the cycle.
8. Seven different biomes are described in your textbook. If you were in charge of global ecosystem conservation but were told you had to focus all of your resources on preserving two of the seven types of biospheres, which would you choose, and why?


Questions specific to this case study:


1. What is meant by the term “biodiversity”?

2. Is there a difference between "invasive species", “non-native” & "exotic species"? 

3. Describe the effect of an invasive species on community structure.

4. Who is being affected by this decision and how?

5. If the decision is made to introduce the Suminoe oysters, what might be the long-term effects on the environment, the communities, the people? Discuss both the beneficial and negative impacts.

 6. Any choice implies other lost opportunities. In what alternative ways might this money be spent to deal with the Chesapeake Bay’s problems and serve constituents?

 7. What might this region look like in 20 years if nothing is done?

 8. What should Senator Ben Fisher do?




*adapted from National Center for Teaching Case Studies

by Valerie Nieman

Department of English and Department of Journalism and Mass Communication

North Carolina A&T State University


Zhi-Jun Liu

Department of Geography

University of North Carolina—Greensboro