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1. Where in the world’s oceans would you likely encounter the lowest level of primary production by phytoplankton?
Along the west coast of a continent
In the central tropical Pacific Ocean
In an area of active upwelling
Offshore from a major river
2. How does El Niño impact commercial fish production along the west coast of South America?
The warm water brought by El Niño speeds up fish production.
The increased nutrients in surface waters associated with El Niño are toxic to phytoplankton.
The warm surface water of an El Niño directly kills large numbers of fish.
The warm surface water of an El Niño stops upwelling, which reduces nutrient renewal in the euphotic zone.
3. How would total salmon catch in the Bristol Bay fishery be affected if pollution from mining, for example, eliminated a salmon population in a major river that drains into Bristol Bay (see Figures 8.29 and 8.30)?
Catches would likely not change.
Catches would likely be more stable over time due to less competition among salmon.
Catches would likely be more variable over time due to lower salmon population diversity.
Catches would likely increase.
4. Approximately what percentage of the world’s fish populations has been depleted to the point where those numbers are now considered “collapsed”?
90%
75%
50%
25%
5. Following dam building, the number of salmon returning to spawn in the Klamath River averaged about 35,000, approximately 10% of the historical average. How many salmon historically returned to the Klamath River to spawn?
90,000
350,000
3,500,000
35,000,000
6. Which of the following is a way in which intensive aquaculture affects aquatic ecosystems?
Intensive aquaculture can pollute aquatic ecosystems.
Intensive aquaculture can enhance the genetic diversity of wild populations.
Intensive aquaculture increases the intensity of fishing for wild fish.
Intensive aquaculture decreases the disease and parasite load on wild fish populations.
7. Which of the following was an indicator of recovery of the Atlantic cod food web off Nova Scotia?
A decline in abundance of zooplankton
An increase in abundance of phytoplankton
An increase in the abundance of forage fish
A decrease in the abundance of forage fish
8. River restoration can involve which of the following?
Planting of native riparian vegetation
Restoring the natural form of river channels
Removing dams
All of the above
9. What percentage of the 150 million metric tons of aquatic organisms harvested in 2011 came from aquaculture?
25%
60%
40%
80%
10. How do marine protected areas contribute to sustaining fishery production?
They do not contribute to sustaining fishery production but instead preserve marine ecosystems for tourism.
Marine protected areas reduce the number of large predaceous fish, so prey fish populations grow.
By reducing the abundance and diversity of marine invertebrates in an area, marine protected areas allow marine fish to flourish.
Marine protected areas support higher biomass and numbers of fish, providing an abundance of juvenile and adult fish that move into areas that can be fished.
Critical Analysis
1. According to the Food and Agriculture Organization of the UN, the people in the nations on the west coast of Africa consumed much more fish per capita than did the people in the nations along the east coast of Africa. Can you explain this difference in terms of availability?
2. Using Internet resources, explore and summarize the role played by international treaties in the management of Atlantic cod and Pacific halibut. Compare the complexity and success of these treaties at sustaining fish harvests.
3. Explore the information and perspectives on the issue of genetically modified (GM) Atlantic salmon and formulate a cogent argument for or against approval of GM salmon for human consumption.
4. Use Figure 8.12 as a basis for reviewing and explaining the changes in the marine food web off Nova Scotia caused by the depletion of Atlantic cod, the top carnivore in that ecosystem. If the cod population does recover, how will the ecosystem change as it returns to something resembling its former state?
5. Discuss the potential cultural changes associated with a shift from “race to fish” to individual transferable quotas (ITQs) as a basis for regulating commercial fishing. How does this regulatory change potentially affect the ways in which fishers view and harvest fish and shellfish populations?