Exercises: Tragedy of the Commons and Overfishing
Define the tragedy of the commons*. Give one example of a shared resource that could suffer from it.
Define the tragedy of the commons. Give one example of a shared resource that could suffer from it.
Name the fishing method in which a large net is dragged along the ocean floor. State one way it harms marine ecosystems.
Name the fishing method in which a large net is dragged along the ocean floor. State one way it harms marine ecosystems.
Classify each practice as surface mining or subsurface mining: (a) mountaintop removal, (b) a coal mine reached by a vertical shaft, (c) strip mining.
Classify each practice as surface mining or subsurface mining: (a) mountaintop removal, (b) a coal mine reached by a vertical shaft, (c) strip mining.
Fishers share an offshore cod fishery with no limits on catch. Each fisher gains by catching more fish, but the cod population falls. Explain how this situation…
Fishers share an offshore cod fishery with no limits on catch. Each fisher gains by catching more fish, but the cod population falls. Explain how this situation illustrates the tragedy of the commons. Then describe two management strategies, such as catch quotas or marine protected areas, that could prevent the collapse of the fishery.
A fishery biologist estimates that a fish population of 500,000 individuals can replace itself while losing 12% per year to harvest. Regulators allow a harvest of 90,000…
A fishery biologist estimates that a fish population of 500,000 individuals can replace itself while losing 12% per year to harvest. Regulators allow a harvest of 90,000 fish this year.
(a) Calculate the sustainable harvest.
(b) Is the allowed harvest sustainable? Explain what is likely to happen to the population if it continues.
Compare clearcutting with selective cutting in a forest. Describe one effect of clearcutting on (a) soil erosion and (b) nearby streams. Then explain why selective…
Compare clearcutting with selective cutting in a forest. Describe one effect of clearcutting on (a) soil erosion and (b) nearby streams. Then explain why selective cutting is often considered less damaging, and name one disadvantage of it.
The table shows the annual catch of a fish species in a regional fishery. | Year | Total catch (thousand tons) | Number of boats | Catch per boat (tons) |…
The table shows the annual catch of a fish species in a regional fishery.
| Year | Total catch (thousand tons) | Number of boats | Catch per boat (tons) |
|---|---|---|---|
| 2000 | 600 | 100 | 6.0 |
| 2010 | 800 | 200 | 4.0 |
| 2020 | 500 | 250 | 2.0 |
(a) Describe the trend in total catch and in catch per boat.
(b) Explain what the data suggest about the health of the fish population, and why catch per boat is a useful measure.
(c) Propose and justify two policies to restore the fishery, and explain one reason fishers might resist them.
A mining company proposes an open-pit copper mine near a river in Arizona. The mine would provide 400 jobs but would expose large quantities of rock and generate waste.…
A mining company proposes an open-pit copper mine near a river in Arizona. The mine would provide 400 jobs but would expose large quantities of rock and generate waste.
(a) Describe two environmental impacts of the mine on land and water, including acid mine drainage.
(b) Explain how reclamation could reduce these impacts, and why it might not fully restore the ecosystem.
(c) Evaluate the proposal by weighing economic benefits against environmental costs, and state what additional information you would want before deciding.