190 Harvesting the Ocean’s Resources
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HARVESTING THE OCEAN’S
RESOURCES
Chapter Outline
COMMERCIAL FISHING
Fisheries Management
Monitoring Fish Populations
Fishery Yield
Problems in Managing Diverse Species
Overfishing
Changes in Genetic Diversity
Salmon
Shellfish
SALT, WATER, AND MINERALS
Mineral Resources
Sulfides
Manganese
SAND AND GRAVEL
Chapter Objectives
• Describe the different ways to manage fisheries.
• Discuss the problems associated with overfishing.
• Explain ways in which fisheries are affected besides overfishing.
Key Terms
renewable resources
stock
tagging
landings
exclusive economic zone
(EEZ)
surimi
incidental catch (bycatch)
raft culture
purse seines
backing down
ocean ranching (sea
Chapter Summary
1. In the past 50 years, the demand for food from the sea has increased, and so has
2. Fisheries biologists study the size, distribution, and basic biology of commercial
3. Overfishing can change the genetic diversity of a population and the species
diversity of ecosystems. Some techniques used in fishing can decrease fish yields by
4. Incidental catch, or bycatch, represents a large waste of marine resources. Current
5. Aquaculture represents a way of increasing the commercial catch. Some aquaculture
6. The cost of commercial fishing is increasing, and because most of the commercial
fishers in the United States are small, independent operators, it is hard for them to
192 Harvesting the Ocean’s Resources
7. Almost one-third of the world’s supply of salt (NaCl) is produced from seawater by
8. The oceans contain vast amounts of minerals, but most of them are difficult to reach
9. The largest seafloor mining operations extract sand and gravel from the seafloor for
Chapter Outline
I. Commercial Fishing
A. Fisheries management.
1. Monitoring fish populations.
a. Determining population distribution and movement.
B. Overfishing.
1. Changes in genetic diversity.
2. Changes in species diversity.
3. Changes in habitat.
c. Consumer education.
C. Other factors affecting marine fisheries.
1. Destruction of coastal habitats.
2. Wasteful and destructive fishing practices.
3. Aquaculture.
a. Fish aquaculture.
b. Raft culture.
D. Case Studies.
1. Anchovies.
2. Tuna.
a. Marine biology and the human connection—bluefin tuna.
3. Salmon.
4. Shellfish.
II. Salt, Water, and Mineral Resources
A. Minerals.
B. Sulfides.
Suggestions for Presenting the Material
1. Assign students to search for fish-based processed food products at the grocery
store, and read the contents of the ingredients listed on the packages. Examine
products such as fish sticks, fish cakes, and other manufactured foods. Are the fish
identified by name? If so, which fish species are most commonly used?
Classroom Discussion Ideas
1. Is aquaculture of top carnivore species (e.g., tuna, salmon, etc.) a realistic option to
feed the world’s hungry? Discuss both the limitations and advantages of the current
technology, as well as the realities of energy limitation moving up the trophic chain.
2. What effects would large-scale manganese nodule mining have on epibenthic deep-
sea communities?
3. Should the short-term economic gains of certain industries that rely on the profits
acquired from public resources be supported by government regulations?
4. Discuss the 1982 international Law of the Sea treaty, and the position taken by the
United States. When marine resources are found in international waters, who do
they belong to? Should they belong to any one nation?
194 Harvesting the Ocean’s Resources
5. Discuss the concept of maximum sustainable yield in fisheries management. Is it a
realistic notion, given that scientists do not have clear estimates of fish populations
to begin with? Why is it still being used to determine fishing quotas and policies?
Videos, Animations, and Websites
Video
Salmonera. (DVD, 2004)
Unflinching documentary examines the environmental repercussions of industrial “Blue
Strange Days on Planet Earth: Dangerous Catch. (DVD, National Geographic, 2008)
Profiles the interrelated problems that result from overharvesting fish.
Empty Oceans, Empty Nets. (DVD, Bullfrog Films, 2003)
Award-winning documentary features some of the world’s most respected marine
scientists who discuss the global fisheries crisis and the innovative research being done
Sharkwater. (DVD, 2007)
Award-winning documentary illuminates the global exploitation of sharks, and
challenges audiences to reexamine traditional fears surrounding these unfairly maligned
Aquaculture. (DVD, 2006)
Profiles three women working in the business, who explain the methods and problems
Animations
AquacultureHub.
Animations to illustrate aquaponics.
Websites
Monterey Bay Aquarium Seafood Watch.
Excellent consumer education on strategies for seafood lovers to make informed and
NOAA Learning Objects: Lesson 12—Food, Water, and Medicine from the Sea.
Animated program discusses historic uses of ocean resources, and presents global
Smithsonian Institution: Educational Materials Associated with the Ocean Planet.
Bibliography of educational resources, lesson plans, and fact sheets related to ocean
World Wildlife Fund.
An overview of aquaculture, the problems of farming oceanic organisms, and possible
Suggested Answers to End of Chapter Questions
Multiple Choice
1. d. sand and gravel
2. d. oil
Matching
1. d.
196 Harvesting the Ocean’s Resources
Short Answer
1. What is the goal of fisheries management?
The goal of fisheries management is to establish policies and limits to prevent
2. In addition to increased mortality rates, what are two other problems associated with
overfishing?
Overfishing upsets ecosystem balance by impacting food chain relationships. It
3. Why is it difficult to accurately determine the size of commercial stocks of fishes and
shellfishes?
Estimating the size of commercial stocks accurately is difficult because of the
4. Compare potential yield with sustainable yield.
The potential yield is defined as the amount of stock that can be removed each year
5. Besides overfishing, what other problems are contributing to the decline in fisheries
production?
Fisheries are in decline due to destruction of coastal nurseries in estuaries (salt
6. What are some benefits of aquaculture?
The benefits of aquaculture include efficient use of resources (especially in
Chapter 19 197
7. What are some ecological problems associated with aquaculture?
Ecological problems associated with aquaculture include: habitat destruction of
8. What is the relationship between the size of the world’s population, fishing effort, and
the size of the commercial catch of fish and shellfish?
The size of the commercial catch of fish and shellfish shows an inverse relationship
9. How does the cost of fishing influence the kinds of fish caught and the methods used
to process them?
As fishing costs increase, valuable rare species are targeted and more sophisticated
10. Considering the vast mineral resources of the sea, why aren’t more minerals mined
from this rich area?
11. Why is it important for the fisheries industry to be regulated?
Without regulation of fisheries, economic self-interest will propel individual
12. Why is it not ecologically sound to use anchovies for livestock feed?
Anchovies are not ecologically suitable to use as a protein source in livestock feed,
13. Why are some commercial fishers opposed to ocean ranching?
Some commercial fishers oppose ocean ranching, fearing that their traditional
198 Harvesting the Ocean’s Resources
Thinking Critically
1. From an ecological standpoint, would it make more sense for humans to eat anchovies
or tuna? Explain.
2. When the size of the commercial catch increases, the size of individual fishes
decreases. Why does this occur?
Net-based fishing methods preferentially catch the larger individuals of a species;
3. Suggest some ways that commercial fishers could decrease the size of their catch
without becoming unemployed or going bankrupt.
The government could require that fishers adopt a certificate-based system that
Suggested InfoTrac® Articles
“Deep Trouble.” Haedrich, R.L. Natural History, (2007).