Download APES STUDY GUIDE Chapter 11

APES STUDY GUIDE
Chapter 11
Sustaining Aquatic Biodiversity
Key Concepts
11-1 Aquatic species and the ecosystem and economic services they provide are threatened by habitat
loss, invasive species, pollution, climate change, and overexploitation, all made worse by the growth of
the human population and resource use.
11-2 We can help to sustain marine biodiversity by using laws and economic incentives to protect species,
setting aside marine reserves to protect ecosystems and ecosystem services, and using community-based
integrated coastal management.
11-3 Sustaining marine fisheries will require improved monitoring of fish and shellfish populations,
cooperative fisheries management among communities and nations, reduction of fishing subsidies, and
careful consumer choices in buying seafood.
11-4 We can maintain the ecosystem and economic services of wetlands by protecting remaining
wetlands and restoring degraded wetlands.
11-5 Freshwater ecosystems are strongly affected by human activities on adjacent lands, and protection of
these ecosystems must include protection of their watersheds.
11-6 Sustaining the world’s aquatic biodiversity requires mapping it, protecting aquatic hotspots, creating
large and fully protected marine reserves, protecting freshwater ecosystems, and restoring degraded
coastal and inland wetlands.
Key Questions and Case Studies
CORE CASE STUDY: The plight of sea turtles.
Sea turtles have been roaming the oceans for more than 100 million years. Today all seven species are in
danger of extinction mostly because of human activities. Trawler fishing has destroyed much sea turtle
habitat. Turtles are hunted for leather, and their eggs are taken for food. Ocean pollution is another major
threat to sea turtles. Rising sea levels will flood many nesting habitats and change ocean currents.
11-1 What are the major threats to aquatic biodiversity and ecosystem services?
A. Three patterns of marine biodiversity are:
1. The greatest marine biodiversity occurs in coral reefs, estuaries, and on the deep-sea ocean
floor.
2. Biodiversity is higher near the coasts because of great variety of producers, habitats, and
nursery areas.
3. Biodiversity is higher in the bottom region than in the surface region of the ocean.
B. The greatest threat to the biodiversity of oceans is loss and degradation of habitats.
1. Coral reefs, mangrove forests, and coastal wetlands are under great pressure from human
activities.
2. Trawling and dredging are major threats to sea bottom habitats.
3. Dams and excessive water withdrawal are destroying freshwater habitats.
C. Harmful invasive species increasingly threaten marine biodiversity.
1. Blamed for 2/3 of fish extinctions in the United States, and may cost the nation about $16
million/hour.
Sustaining Aquatic Biodiversity
SCIENCE FOCUS: How invasive carp have muddied some waters.
Lake Wingra in Wisconsin receives excessive nutrients from runoff and is populated by invasive
species, including carp and purple loosestrife. The carp devour the algae that would normally
stabilize sediments on the lake bottom. Scientific experiments that involved excluding carp from a
study area showed that algae recolonized and the lake water became noticeably clearer. There is now
an effort to remove the carp from the rest of the lake to alleviate the effects of this invasive species.
SCIENCE FOCUS: Ocean acidification: the other CO2 problem.
Ocean water is basic. When atmospheric CO2 combines with ocean water it forms carbonic acid
(H2CO3). As ocean water becomes less basic, the level of carbonate ions drops. Many aquatic
species use carbonate ions to produce calcium carbonate. Harmful effects are already being felt. In
Oregon, oyster larvae have died off in large numbers in recent years. According to most scientists,
the only way to slow these changes is through a quick and sharp reduction in the use of fossil fuels
around the world.
D. By 2020, 80% of the world’s population will live near coasts. Population growth and pollution
have drastic effects on ocean systems.
1. Pollutants such as nitrogen from fertilizers can cause algal blooms and eutrophication.
2. Toxic pollutants can kill some aquatic life forms.
3. Plastic garbage in the oceans is having detrimental effects on wildlife.
E. Climate change threatens aquatic biodiversity and ecosystems services.
F. Overfishing can have drastic effects on biodiversity.
1. Global fishing is taking 57% more than sustainable yield.
2. Overfishing can lead to commercial extinction, which occurs when it is no longer profitable to
continue fishing the affected species.
3. When populations of predatory species dwindle, invasives can take over.
CASE STUDY: The great jellyfish invasion.
Jellyfish are often found in large swarms or blooms of thousands, even millions of individuals. In
recent years, the numbers of these blooms observed by scientists and fishers have been rising and
more frequent jellyfish stings have had a harmful economic effect on a number of popular tourist
beach areas. Each year, the stings of lethal jellyfish kill dozens of people—far more than the annual
average number of people killed by sharks. In addition, jellyfish blooms often cause beach closings,
disrupt commercial fishing operations by clogging nets, and close down coal-burning and nuclear
power plants by clogging their cooling water intakes.
CASE STUDY: Why should we protect sharks?
Sharks are a keystone species. Media coverage of shark attacks greatly exaggerates the danger from
sharks. For every shark that injures or kills a person, people kill about 1.2 million sharks. About 32%
of the world’s open-ocean shark species are threatened with extinction. Sharks are especially
vulnerable to population declines because they grow slowly, mature late, and have only a few
offspring per generation.
A. Many fish species are threatened with extinction.
1. 27% of marine species and 71% of freshwater species may face extinction within the next 6070 years.
11-2 How can we protect and sustain marine biodiversity?
A. Protecting marine biodiversity is challenging because it is difficult to monitor the impact of the
human ecological footprint, oceans are unseen by most people, oceans are often thought to be
inexhaustible resources, and most of the ocean area lies outside of the jurisdiction of any nation.
1. National and international laws and treaties include CITES, the 1979 Global Treaty on
Migratory Species, the US Marine Mammal Protection Act, the Endangered Species Act, the
U.S. Whale Conservation and Protection Act, and the International Convention on
Biological Diversity.
Instructor's Manual: Chapter 11
B. Biodiversity can be valuable to local communities that develop eco-tourism markets.
C. A country’s offshore fishing zone extends 370 kilometers from its shores.
1. Ocean areas beyond these Exclusive Economic Zones, called the high seas, are difficult to
monitor.
2. The World Conservation Union helped establish a global system of marine protected areas
(MPAs).
3. There are about 4,000 MPAs; however, most MPAs allow ecologically harmful activities like
trawling, dredging, and resource extraction.
D. Scientists are advocating an ecosystems approach to sustaining marine biodiversity.
1. This would entail a network of protect marine reserves, closed to extractive activities.
2. Studies show that fish are larger, reproduce more often, and are present in greater variety.
3. Less that 1% of the world’s ocean area is closed to fishing in marine reserves.
E. Reconciliation ecology can be directed at bringing back reefs, mangrove forests, coastal marshes
and sea grass beds.
F. Integrated coastal management is a community-based effort to develop and use coastal resources
more sustainably.
1. The idea is to find cost-effective, adaptable solutions to preserve biodiversity while meeting
economic and social needs.
11-3 How should we manage and sustain marine fisheries?
A. One way to prevent overfishing is to develop better ways to protect fish populations. The
maximum sustained yield mathematical model is used, but indications are that it has hastened the
collapse of most commercially valuable stocks for several reasons.
B. Optimum sustained yield is a concept that takes into account interactions with other species and
allows more room for error. Another approach is multi-species management of a number of
interaction species, which accounts for competition and predator-prey interactions.
1. There has been limited management of several large marine systems, such as the
Mediterranean Sea.
2. Many fisheries scientists and environmentalists are interested in using the precautionary
principle for management of fisheries and marine systems.
C. Some fishing communities regulate fish harvests on their own and others work with the
government to regulate them. Influx of large modern fishing boats and fleets has weakened the
ability to regulate and sustain local fisheries. Many community management systems are now comanaged, where community and government work together to manage fisheries.
1. Central government sets quotas for various species and divides the quotas among
communities.
2. Government may also limit fishing seasons and regulate gear to be used.
3. Each community then allocates its quota among members.
D. Government subsidies that are intended to keep businesses afloat can encourage overfishing.
E. Individual transfer rights (ITRs) are assigned to each fisherman, and these can then be bought,
sold, or leased like private property.
F. Individuals can help sustain aquatic diversity by demanding sustainably harvested seafood.
1. Labeling seafood would inform consumers.
11-4 How should we protect and sustain wetlands?
A. Coastal and inland wetlands are important reservoirs of aquatic biodiversity; they provide
ecological and economic services.
1. Despite their value, the U.S. has lost more than half of its coastal and inland wetlands since
1900.
Sustaining Aquatic Biodiversity
2. Wetland loss in the U.S. will get worse as global warming leads to rising sea levels, which will
put many coastal wetlands under water.
B. In the U.S., a federal permit is required to fill or deposit dredge material into many wetlands.
1. The U.S. federal policy is a zero net loss goal; mitigation banking allows destruction of some
wetlands as long as the same type of wetland is created elsewhere.
CASE STUDY: Can we restore the Florida Everglades?
An ambitious restoration project is trying to undo the human damage in South Florida’s Everglades.
The natural Everglades is half its original size and is drying out, leaving it vulnerable to fire and
invasion by nonnative species. Everglades National Park was set up in the lower part of the
Everglades, but water didn’t flow into it and human activity caused disturbances. Ninety percent of
the wading birds are gone and other vertebrates are reduced in number by 75–95%. Florida Bay has
become saltier and warmer due to lack of water flow from the Everglades and the Kissimmee River.
Loss of water flow and input from crop fields and cities has caused large algal blooms on the bay.
These blooms threaten coral reefs and hinder diving, fishing, and the tourist industry of the bay and
the Florida Keys. The U.S. Army Corp of Engineers has begun a restoration project funded by the
state and the federal government to restore the meandering river and flow of water to the Everglades.
It has several ambitious goals, which include restoring curving flow of more than half of the
Kissimmee River, removing 250 miles of canals and levees south of Lake Okeechobee, buying 93
square miles of farmland and allowing it to flood to create artificial marshes, creating a network of
artificial marshes, creating 18 large reservoirs to ensure water for south Florida’s present and future
population and the lower Everglades, and building new canals, reservoirs, and pumping stations to
capture and return to the Everglades 80% of the water flowing out to sea.
11-5 How can we protect and sustain freshwater lakes, rivers, and fisheries?
A. There are many threats to freshwater ecosystems, including habitat destruction, invasive species,
climate change and overharvesting fish.
CASE STUDY: Can the Great Lakes survive repeated invasion by alien species? Invasions by
nonnative species have upset the ecological functioning of the Great Lakes for decades, with more
invaders coming. At least 162 nonnative species have invaded the Great Lakes since the 1920s.
Measures have been taken to control a number of these species. Sea lampreys are one of the biggest
threats and have depleted a number of the sport fish species in the lakes.
Zebra mussels were brought into the lakes in ballast and have become very aggressive pests since
they have no known natural enemies. They have displaced native mussel species, clogged pipes and
piers, fouled beaches, and have spread to other parts of the U.S. Quagga mussels invaded the Great
Lakes in 1991 and Asian Carp are now found within a few miles of Lake Michigan..
B. Rivers/streams are important ecological and economic resources, but they can be degraded by
overfishing, pollution, dams, and water withdrawal.
C. The Columbia River has been altered by 119 dams and withdrawal of water for agriculture.
D. To protect rivers and lakes from excess pollutants, watersheds need to be protected.
E. The National Wild and Scenic Rivers Act was passed in 1968 to protect rivers and river segments
with outstanding scenic, recreational, geological, wildlife, historical, or cultural values.
F. Congress established a three-tiered classification scheme:
1. Wild rivers are relatively inaccessible; they are not permitted to be widened, straightened,
dredges, filled or dammed.
2. Scenic rivers are free from dams, mostly undeveloped, of great scenic value, and accessible in
some places by roads.
3. Recreational rivers are readily accessible by roads and may have some dams or development
along their shores.
4. In 2009, Congress increased the total length of wild and scenic rivers by half. Still, less than
1% of the country’s total river length is protected.
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G. Sustainable management of freshwater fish involves encouraging populations of
commercial/sport fish species, prevents overfishing, and reduces or eliminated less desirable fish
populations.
11-6 What should be our priorities for sustaining aquatic biodiversity?
A. There is evidence that the harmful effects of human activities on biodiversity can be reversed
over the next two decades.
1. This must entail an ecosystem approach to protecting biodiversity.
2. Priorities should be mapping aquatic biodiversity, identifying and preserving hotspots,
creating fully protected marine reserves, protecting and restoring lakes and rivers, initiating
ecological restoration projects worldwide, and finding ways to raise the incomes of people
who live near protected waters.
Key Terms
fishery
fishprint
Term Paper Research Topics
1.
Food resources obtained from aquatic ecosystems
2.
Resources (other than food) obtained from aquatic ecosystems
3.
Damage caused by human activities in aquatic environments
4.
Problems and solutions associated with overfishing
5.
Strategies to protect marine environments
6.
Ecological services of wetlands and wetland restoration projects
7.
Wetlands protection
8.
Prevention of beach erosion
9.
Coastal cleanup strategies
10. Endangered species of the coast
11. What can be done to prevent coral bleaching?
Discussion Topics
1.
What is the best way to manage coastal development to both provide protection and economic use of
the resource?
2.
What is the value of wetland areas?
Sustaining Aquatic Biodiversity
3.
Is development of beachfront property for human recreation worth the potential danger from hazards
associated with the coastal environment?
4.
Are developed countries exploiting the marine resources of developing countries?
5.
Should the United States take a global leadership role in protecting marine ecosystems? Why or why
not?
Activities and Projects
1.
As a class field trip, visit a coastal area, managed lake, or wetland area. Invite a biologist/ecologist to
explain the processes taking place in the system. What specific methods are used to curb ecosystem
damage in managed systems?
2.
Invite a representative of an agency involved with aquatic system management to speak to the class
about issues regarding the agency’s impacts on the resource, the public’s benefit from the agency’s
management, and what the agency is doing to minimize the ecological impacts of their activities.
3.
Consider the ecological problems that confront(ed) Lake Victoria in East Africa and the Great Lakes
in the United States. How are the factors that harm(ed) ecological diversity similar and how are they
different? What lessons can the United States learn from the devastation in Lake Victoria?
4.
Are inland wetlands being drained and filled in your locale? Is there a nearby stream or river being
subjected to excessive levels of pollution? Is it feasible for you and your class to "adopt" one of these
disturbed ecosystems and help restore it to health?
5.
Arrange a debate on the problems and alternatives of coastal zone management. Debate the
proposition that we should severely restrict engineering approaches to beach stabilization and adopt a
"retreat from the beach" strategy, emphasizing the preservation of coastal ecosystems and the
ecosystem services they provide.
Attitudes and Values
1.
Have you ever visited developed seashore? How did you feel about the patterns of development? Do
you think this type of development should be allowed to continue?
2.
What benefits do you receive from aquatic ecosystems where you live?
3.
Where are the nearest locations in your area to go to observe aquatic ecosystems? What kinds of
aquatic ecosystems occur where you live?
4.
What are your feelings toward aquatic ecosystems?
5.
Do you feel that humans have the right to develop aquatic ecosystems in any way they wish? If not,
what limits do you see on human behavior toward aquatic ecosystems?
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6.
Do you use products that come from the ocean? Do the products you use result in destruction of, or
the continued sustainable use of, the ocean?
7.
How do you feel when you see pictures of the beach erosion and economic loss following a
hurricane?
Suggested Answers to End of Chapter Review Questions
Review Questions
1. Core Case Study. Describe the status of sea turtles and explain how human activities are threatening
their existence.
 Sea turtles have existed for more than 100 million years. Today all seven species of sea turtle are
in danger of extinction. Trawler fishing has destroyed much sea turtle habitat. Sea turtles are
hunted for leather and their eggs are taken for food. They often drown after becoming entangled in
nets. Pollution of ocean water also threatens sea turtles. Artificial lights can confuse newly hatched
turtles. Sea level rise will flood many nesting habitats and change ocean currents.
2. Section 11-1. What is the key concept for this section? How much do we know about the habitats and
species that make up the earth’s aquatic biodiversity? What are three general patterns of marine
biodiversity? Describe the threat to marine biodiversity from bottom trawling. How have coral reefs
been threatened? What is ocean acidification? What are two causes of disruption of freshwater
habitats?
 Key concept: Aquatic species and the ecosystem and economic services they provide are
threatened by habitat loss, invasive species, pollution, climate change, and overexploitation, all
made worse by the growth of the human population and resource use.
 Only about 5% of the earth’s oceans have been explored and we know relatively little about its
biodiversity.
 First, the greatest marine biodiversity occurs in coral reefs, estuaries, and the deep- ocean floor.
Second, biodiversity is higher near coasts than in the open sea because of the greater variety of
producers and habitats in coastal areas. Third, biodiversity is higher in the bottom region of the
ocean than in the surface region because of the greater variety of habitats and food sources on the
ocean bottom.
 Bottom trawling causes loss and degradation of many sea-bottom habitats. Trawlers drag huge
nets weighted down with heavy chains and steel plates like giant submerged bulldozers over
ocean bottoms to harvest a few species of bottom fish and shellfish. Trawling nets reduce coral
reef habitats to rubble and kill a variety of creatures on the bottom by crushing them, burying
them in sediment, and exposing them to predators. Each year, thousands of trawlers scrape and
disturb an area of ocean floor about 150 times larger than the area of forests that are clear- cut
annually.
 Coral reefs are threatened by development, pollution, and ocean acidification resulting from
greatly increased levels of carbon dioxide emissions.
 Ocean acidification is the increasing acidity of ocean waters due to the absorption of CO2 from
the atmosphere.
 Habitat disruption is a major problem in freshwater systems. The main causes of disruption are
dam building and excessive water withdrawal. Many of the world’s freshwater wetlands have
Sustaining Aquatic Biodiversity
been destroyed. Invasive species, pollution, and climate change threaten many freshwater
ecosystems and freshwater fish stocks are overharvested.
3. Give two examples of threats to aquatic systems from invasive species and two examples of the same
for freshwater systems. What are two harmful effects on aquatic systems resulting from the increase
in the human population in coastal areas? Give two examples of how pollution is affecting aquatic
systems. What are three ways in which projected climate change could threaten aquatic biodiversity?
Explain how ocean acidification occurs and why it is a serious problem.
 Two examples of invasive species are the Asian swamp eel and purple loose strife. The Asian
swamp eel has invaded the water-ways of south Florida (U.S.). This rapidly reproducing eel eats
almost anything. It can elude cold weather, drought, and predators by burrowing into mud banks.
It is resistant to waterborne poisons because it can breathe air, and it can wriggle across dry land
to invade new waterways. Eventually, this eel could take over much of the waterways of the
southeastern United States. The purple loose strife is a perennial plant that grows in wetlands in
parts of Europe. Since the 1880s, it has been imported and used in gardens as an ornamental plant
in many parts of the world. A single plant can produce more than 2.5 million seeds a year, which
are spread by flowing water and by becoming attached to wildlife, livestock, hikers, and vehicle
tire treads. It reduces wetland biodiversity by displacing native vegetation and reducing habitat
for some forms of wetland wildlife. An example from marine environments is an invasive brown
seaweed called Undaria, or wakame, which is spreading along the California coast. It grows
rapidly and forms thick forests, choking out native kelps that provide habitat for sea otters.
Another marine example is the lionfish, which competes with popular reef fish species like
grouper and snapper, taking their food and eating their young.
 Two harmful effects resulting from human populations are habitat destruction and increased
pollution.
 Nitrate fertilizers can cause algal blooms and disrupt ecosystem services, and the influx of toxic
pollutants can poison aquatic life.
 Climate change is expected to cause substantial sea level rise, which will result in declining coral
reefs, the disappearance of low-lying islands, and the swamping of productive coastal wetlands.
 Ocean acidification occurs when atmospheric CO2 combines with ocean water to form carbonic
acid (H2CO3). As ocean water becomes more acidic, the levels of carbonate ions decrease. Many
ocean species use carbonate ions to build calcium carbonate.
4. Define fishery. What are three major harmful effects of overfishing? Describe the effects of trawler
fishing, purse- seine fishing, longlining, and drift-net fishing. What is bycatch? What is a fishprint?
Summarize the collapse of the Atlantic cod fishery. Explain how marine mammals are threatened by
overfishing and give an example. Summarize the story of jellyfish invasions. Summarize the
arguments for protecting sharks. About what percentage of freshwater species are in danger of
extinction?
 A fishery is a concentration of a particular wild aquatic species suitable for commercial
harvesting.
 Three major effects of overfishing are that large individuals become scarce, as large species
become overfished the fishing industry shifts its focus to smaller species, and as larger predatory
species dwindle invasive species can take over.
 The harmful ecological effects of:
o Trawler fishing—major threat is loss and degradation of many sea-bottom habitats because
trawlers drag huge nets weighted down with heavy chains and steel plates over ocean bottoms
to harvest a few species of bottom fish and shellfish.
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o
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Purse-seine fishing—uses nets to capture fish, but also have killed large numbers of dolphins
that swim on the surface above schools of tuna.
o Longlining—hooks and kills large numbers of endangered sea turtles, dolphins, and seabirds
each year.
o Driftnet fishing—can lead to overfishing of the desired species and may trap and kill large
quantities of unwanted fish, marine mammals, sea turtles, and seabirds.
Bycatch is the unwanted fish that are harvested in fishing operations.
The fishprint is defined as the area of ocean needed to sustain the consumption of an average
person, a nation, or the world.
In 1992, Canada’s 500-year-old Atlantic cod fishery off the coast of Newfoundland collapsed and
was closed. This put at least 20,000 fishers and fish processors out of work and severely damaged
Newfoundland’s economy. After the cod were fished out, fishers began harvesting sharks, which
provide important ecosystem services and help to control the populations of other species. Since
then, overfishing of big sharks has cut Atlantic stocks of those species by 99%. With the large
sharks essentially gone from the northwest Atlantic, populations of rays and skates, which the
sharks once fed on, have exploded and have wiped out most of the region’s bay scallops, which in
turn had served as a food source for other species, including humans. As large species are
overfished, the fishing industry has begun working its way down marine food webs by shifting to
smaller species. This reduces the breeding stock needed for recovery of depleted species, which
unravels marine food webs and disrupts marine ecosystems and their ecosystem services.
The most prominent marine mammal threatened by fishing is the Blue whale. Blue whales have
been hunted for their oil, meat and bone. As a result, their population has declined from 250,000
in 1900 to less than 5,000 today.
Jellyfish are often found in swarms or blooms. Overfishing of fish species that eat small jellyfish
has led to some exploding populations. Excessive plant nutrients from fertilizer runoff spurs the
growth of phytoplankton, on which jellyfish feed.
Sharks should be protected because they are often keystone species in their ecosystems.
About 71% of the world’s freshwater fish species are threatened with extinction.
5. Section 11-2. What is the key concept for this section? How have laws and treaties been used to help
sustain aquatic species? What is the main problem that interferes with enforcing international
agreements? Describe international efforts to protect whales from overhunting and premature
extinction. How can economic incentives help sustain aquatic diversity? Give an example of how
this can happen.
 Key concept: We can help to sustain marine biodiversity by using laws and economic incentives to
protect species, setting aside marine reserves to protect ecosystems and ecosystem services, and
using community-based integrated coastal management.
 The U.S. Endangered Species Act and international agreements have been used to identify and
protect endangered and threatened marine species such as seals, sea lions, sea turtles, and whales.
National and international laws and treaties to help protect marine species include the 1975
Convention on International Trade in Endangered Species, the 1979 Global Treaty on Migratory
Species, the U. S. Marine Mammal Protection Act of 1972, the U. S. Endangered Species Act of
1973, the U. S. Whale Conservation and Protection Act of 1976, and the 1995 International
Convention on Biological Diversity.
 It is difficult to get all nations to comply with international agreements, which can weaken their
effectiveness.
 In 1946, the International Convention for the Regulation of Whaling established the International
Whaling Commission. Its mission was to regulate the whaling industry by setting annual quotas to
prevent overharvesting and commercial extinction. But IWC quotas often were based on
inadequate data or were ignored by whaling countries. Without powers of enforcement, the IWC
Sustaining Aquatic Biodiversity
was not able to stop the decline of most commercially hunted whale species. In 1970, the United
States stopped all commercial whaling and banned all imports of whale products. The IWC
imposed a moratorium on commercial whaling starting in 1986. It worked. The estimated number
of whales killed commercially worldwide dropped from 42,480 in 1970 to about 1,400 in 2009.
However, despite the ban, more than 33,000 whales s were hunted and killed between 1986 and
2010.
 Conserving biodiversity can prove to be more valuable to communities than the harvesting and
selling of these resources by providing a foundation for ecotourism. This has occurred in Florida
and Costa Rica with the sea turtle populations.
6. Explain how marine protected areas and marine reserves to help sustain aquatic biodiversity and
ecosystem services. What are marine hotspots? What percentage of the world’s oceans is strictly
protected from harmful human activities in marine reserves? Summarize the contributions of Sylvia
Earle to the protection of aquatic biodiversity. Give two examples of how marine systems can be
restored. Describe the roles of fishing communities and individual consumers in regulating fishing
and coastal development. Describe threats from increasing ocean acidity. What is integrated coastal
management?
 Protecting marine biodiversity in marine protected areas and marine reserves helps maintain
biodiversity and provides ecosystem services because the natural processes still occur without as
much human degradation of the resource.
 Marine hotspots are areas in need of full protection because of their importance to marine
biodiversity and ecosystem services.
 Despite their importance, less than 1% of the world’s oceans are closed to fishing and other
harmful human activities in marine reserves, and only 0.1% are fully protected—compared to 5%
of the world’s land. Thus, humans have reserved essentially 99.9% of the world’s oceans to use as
they see fit. Many marine scientists argue that in order to sustain marine biodiversity, we must
protect at least 30% of the world’s oceans as marine reserves.
 Sylvia Earle has led more than 100 ocean research expeditions focused on ecology and
conservation of marine systems. She has founded three companies devoted to developing
submarines and other devices for deep-sea exploration and research.
 Two examples of the restoration of marine systems include the Japan’s attempt to restore its
largest coral reef by seeding it with new corals, and the attempt in Israel to heal coral fragments at
an ecotourism restaurant and rebuild the surrounding reef.
 Rising acidity can kill off coral reefs, make the seawater less able to absorb sounds generated by
humans (thus affecting whales), and dissolve the calcium carbonate of which the structures of
corals and shellfish are comprised.
 Coastal communities can establish integrated coastal management in which fishers, scientists,
conservationists, citizens, business interests, developers, and politicians collaborate to develop and
use coastal areas and resources more sustainably.
 Coastal communities must closely monitor and regulate fishing and coastal land development and
prevent pollution from land- based activities. Coastal residents must also think carefully about the
chemicals they put on their lawns, and the kinds of waste they generate and where it ends up. And
individuals can reduce their carbon footprints to slow climate change and its numerous harmful
effects on marine and other ecosystems.
 One strategy emerging in some coastal communities is integrated coastal management— a
community- based effort to develop and use coastal resources more sustainably. The goal is for
fishers, business owners, developers, scientists, citizens, and politicians to identify shared
problems and goals in their use of marine resources. The idea is to develop solutions that help to
preserve biodiversity and environmental quality while also meeting various economic and social
goals. This requires all participants to seek reasonable short- term trade- offs that can lead to longInstructor's Manual: Chapter 11
term ecological and economic benefits. For example, fishers might have to give up fishing in
certain areas until stocks recover enough to restore biodiversity in those areas, which might then
provide fishers with a more sustain-able future for their businesses.
7. Section 11-3. What is the key concept for this section? Describe three ways to estimate the sizes of
fish populations and list their limitations. How can the precautionary principle help in managing
fisheries and large marine systems? What are catch-share and co-management systems and how can
they help to sustain fisheries? How can government subsidies encourage overfishing? Explain how
consumer choices can help to sustain fisheries and aquatic biodiversity and ecosystem services. List
five ways to manage global fisheries more sustainably.
 Key concept: Sustaining marine fisheries will require improved monitoring of fish and shellfish
populations, cooperative fisheries management among communities and nations, reduction of
fishing subsidies, and careful consumer choices in buying seafood.
 The traditional approach to estimating the size of a fish populations has used a maximum
sustained yield model to project the maximum number of fish that can be harvested annually from
a fish stock without causing a population drop. However, the MSY concept has not worked very
well because of the difficulty in estimating the populations and growth rates of fish stocks. Also,
harvesting a particular species at its estimated maximum sustainable level can affect the
populations of other target and nontarget fish species and other marine organisms. In recent years,
the optimum sustained yield concept has been used. It attempts to take into account interactions
among species and to provide more room for error. Similarly, another approach is multispecies
management of a number of interacting species, which takes into account their competitive and
predator–prey interactions. An even more ambitious approach is to develop complex computer
models for managing multispecies fisheries in large marine systems. However, it is a political
challenge to get groups of nations to cooperate in planning and managing such large systems.
There are uncertainties built into any of these approaches because there is much to learn about the
biology of fishes and because of changing ocean conditions.
 Using the precautionary principle for managing fisheries and large marine systems means sharply
reducing fish harvests and closing some overfished areas until they recover and until we have
more information about what levels of fishing can be sustained.
 Catch-share systems allow each fisher a share of the total allowable catch. Co-management
systems allow coastal communities and the government to work together to manage fisheries.
 Governments around the world give a total of about $ 30–34 billion per year to fishers to help
them keep their businesses running. Some marine scientists argue that, each year, $ 10–14 billion
of these subsidies are spent to encourage overfishing and expansion of the fishing industry.
 Bottom- up pressure from consumers demanding sustainable seafood will encourage more
responsible fishing practices and thus help sustain aquatic biodiversity and ecosystem services.
Consumers can choose seafood that has the Fish Forever” eco- label that certifies that the seafood
was caught using environmentally sound and socially responsible practices.
 Ways to manage global fisheries more sustainably include setting low catch limits, improving
monitoring and enforcement, certifying sustainable fisheries, establishing no-fishing areas, and
using nets that allow smaller fish to escape.
8. Section 11-4. What is the key concept for this section? What percentage of the U. S. coastal and
inland wetlands has been destroyed since 1900? What are the major threats to wetland and their
ecosystem services? How does the United States attempt to reduce wetland losses? Summarize the
story of efforts to restore the Florida Everglades.
 Key concept: We can maintain the ecosystem and economic services of wetlands by protecting
remaining wetlands and restoring degraded wetlands.
Sustaining Aquatic Biodiversity
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The United States has lost more than half of its coastal and inland wetlands since 1900.
Ecological services provided by wetlands include:
o Filtering and degrading toxic wastes and pollutants
o Reducing flooding and erosion by absorbing storm water and releasing it slowly and by
absorbing overflows from streams and lakes
o Helping to replenish stream flows during dry periods
o Helping to recharge groundwater aquifers
o Helping to maintain biodiversity by providing habitats for a variety of species
Zoning laws can be used to steer development away from wetlands. A U. S. law requires a federal
permit to fill in or to deposit dredged material into wetlands occupying more than three acres.
However, only about 6% of remaining U. S. inland wetlands are under federal protection, and
state and local wetland protection is inconsistent and generally weak. The stated goal of current
U. S. federal policy is zero net loss in the function and value of coastal and inland wetlands. A
policy known as mitigation banking allows destruction of existing wetlands as long as an equal
area of the same type of wetland is created or restored. However, a 2001 found that at least half of
the attempts to create new wetlands failed to replace lost ones, and most of the created wetlands
did not provide the ecological functions of natural wetlands. Private investment bankers make
money by buying wetland areas and restoring or upgrading them. This creates wetland banks or
credits that they can sell to developers.
The efforts to restore the Florida Everglades revolve around five goals.
o Restore the curving flow of more than half of the Kissimmee River.
o Remove 400 kilometers of canals and levees blocking water flow south of Lake Okeechobee.
o Buy 240 square kilometers of farmland and allow it to be flooded to create artificial marshes
that will filter out agricultural runoff.
o Create 18 large reservoirs and underground water storage areas to ensure an adequate water
supply for the lower Everglades and for south Florida’s population.
o Build new canals, reservoirs, and pumping systems to capture 80% of the water currently
flowing out to sea and return it to the Everglades.
9. Section 11-5. What is the key concept for this section? Describe the major threats to the world’s
rivers and other freshwater systems. Explain how invasions of nonnative species are threatening the
Great Lakes. What are some ways to help sustain river systems? What are three ways to protect
freshwater habitats and fisheries?
 Key concept: Freshwater ecosystems are strongly affected by human activities on adjacent lands,
and protection of these ecosystems must include protection of their watersheds.
 Human activities are disrupting and degrading freshwater systems. Forty percent of the world’s
rivers have been dammed or otherwise engineered and vast portions of the world’s freshwater
wetlands have been destroyed. Worldwide, aquatic species have been crowded out of at least half
of their habitat areas. Invasive species, pollution, and climate change threaten the ecosystems of
lakes, rivers, and wetlands. Freshwater fish stocks are overharvested. Increasing human
population pressures and global warming make these threats worse.
 The Great Lakes have been invaded by at least 162 nonnative species and the number keeps
rising. Many of the alien invaders arrive on the hulls or in bilge-water discharges of oceangoing
ships.
 Freshwater ecosystems can be protected through laws, economic incentives, and restoration
efforts. Restoring rivers will probably require taking down some dams and restoring river flows.
In 1968, the U. S. Congress passed the National Wild and Scenic Rivers Act to establish
protection of rivers with outstanding scenic, recreational, geological, wildlife, historical, or
cultural values.
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Three ways to protect freshwater habitats and fisheries include supporting populations of
commercial and sport fish species, preventing such species from being overfished, and reducing
or eliminating populations of harmful invasive species.
10. Section 11-6. What is the key concept for this section? List six priorities for applying the ecosystem
approach to sustaining aquatic biodiversity. What are the three big ideas of this chapter? How can we
apply the three scientific principles of sustainability in efforts to protect sea turtles from extinction
(Core Case Study) and in helping to sustain aquatic biodiversity and ecosystem services?
 Key concept: Sustaining the world’s aquatic biodiversity requires mapping it, protecting aquatic
hotspots, creating large and fully protected marine reserves, protecting freshwater ecosystems,
and restoring degraded coastal and inland wetlands.
 The ecosystem approach involves:
o Completing the mapping of the world’s aquatic biodiversity.
o Identifying and preserving the world’s aquatic biodiversity hotspots.
o Creating large and fully protected marine reserves.
o Protecting and restoring the world’s lakes and river systems.
o Initiating ecological restoration projects worldwide.
o Finding ways to raise the incomes of people who live in or near protected lands and waters.
 The three big ideas:
o The world’s aquatic systems provide important ecological and economic services, and
scientific investigation of these poorly understood ecosystems could lead to immense
ecological and economic benefits.
o Aquatic ecosystems and fisheries are being severely degraded by human activities that lead to
aquatic habitat disruption and loss of biodiversity.
o We can sustain aquatic biodiversity by establishing protected sanctuaries, managing coastal
development, reducing water pollution, and preventing overfishing.
 The three principles of sustainability involve valuing and protecting biodiversity in these systems.
In so doing, the cycling of nutrients through such systems would be protected, and the reliance on
solar energy to sustain the trophic pyramid would be ensured.
Critical Thinking
The following are examples of the material that should be contained in possible student answers to the
end of chapter Critical Thinking questions. They represent only a summary overview and serve to
highlight the core concepts that are addressed in the text. It should be anticipated that the students will
provide more in-depth and detailed responses to the questions depending on an individual instructor’s
stated expectations.
1. Why could sea turtles (Core Case Study) be considered indicator species? What does the plight of
the world’s sea turtles indicate about the ways in which we treat marine ecosystems?
Sea turtles are highly susceptible to habitat change and thus are good indicator species. The fact
that all seven species of sea turtle are threatened indicates that we do not care for marine
ecosystems.
2. Write a short essay describing how each of the six factors summarized by HIPPCO has affected
sea turtles (Core Case Study) or will affect them further. Look for and describe connections
among these factors. For example, how does one factor enhance the effects of one or more other
factors? Suggest ways in which each of the factors could be reduced.
Sustaining Aquatic Biodiversity
Habitat Loss: The oceans that provide habitat for sea turtles have been greatly compromised by
overharvesting of resources and pollution.
Invasives: The oceans are known to have many invasives, which disrupt ecological services.
Population: Human population puts pressure on coastal environments.
Pollution: Population pressures lead to pollution that ends up downstream, ultimately collecting
in our oceans.
Climate change: Also, related to population and overconsumption of resources, climate change is
altering the pH of oceans and leading to changes in migration timing for many species.
Overfishing: This had obviously been paramount in bringing on the decline of sea turtle species.
Most of these factors point to human population growth and overconsumption of resources as root
causes. Some approaches to alleviating the problem would be to lessen the amount of pollution
we generate, take less resources from the oceans, limit the crowding near coastlines, and be more
responsible about our waste products, many of which flow downstream and end up in the oceans.
3. What do you think are the three greatest threats to aquatic biodiversity and ecosystem services?
For each of them, explain your thinking. Overall, why are aquatic species more vulnerable to
premature extinction from human activities than terrestrial species are? Why is it more difficult to
identify and protect endangered marine species than to protect endangered terrestrial species?
I think that three of the greatest threats to aquatic biodiversity are habitat destruction, increased
pollution from increasing population growth, and overharvesting. Aquatic species are more
vulnerable to premature extinction due to the delicate balance of marine and freshwater
ecosystems. Small changes in pH or temperature changes in the water can have a major affect on
aquatic areas, for example, coral reefs and fish-spawning grounds. Also, because we cannot
actually “see” what is living under the surface of the oceans, lakes, and seas, there is danger of
harvesting species in numbers that exceed the maximum sustainable yield. On the land, if you cut
down a forest you can see that it has gone, but you cannot look into the ocean and directly relate
to the impact that overfishing is having as it is “hidden” from view. For this reason it is difficult
to identify and monitor rare species in aquatic environments. Also, it is very difficult to protect
species that range over parts of the ocean that are not under the jurisdiction of any nation.
4. Why should you be concerned about jellyfish populations taking over large areas of the ocean?
Why can jellyfish be considered an indicator species, and what does the explosion of jelly fish
populations indicate about marine ecosystems? What are three things you would do to try to slow
the changes in the world’s aquatic ecosystems that have likely caused the rise of jellyfish
populations?
Jellyfish are extremely dangerous to humans and some other ocean-dwelling organisms.
Jellyfish can be considered indicator species because they have responded quickly to
changing environmental conditions. Each student’s three ideas will vary.
5. Why do you think no-fishing marine reserves recover their biodiversity faster and more surely
than do areas where fishing is allowed but restricted? Explain.
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The most obvious reason is that populations will grow faster when they are not being harvested
from outside of the system. There will always be predation, but harvesting adds another obstacle
to the growth of the population. Additionally, when fishing is allowed but restricted, it can be
very difficult to monitor the catch to make sure that it is in compliance with regulations.
6. How might continued overfishing of marine species affect your lifestyle? How could it affect the
lives of any children or grandchildren you might have? What are three things you could do to
help prevent overfishing?
Continued overfishing will have the effect of diminishing the biodiversity in our oceans and
severely disrupting ecosystem function as food webs are disturbed. Ultimately, invasive species
will spread widely as these populations dwindle. This means that seafood lovers, and those who
like to observe nature through whale watching or SCUBA diving will inevitably have to sacrifice
something they enjoy. To prevent overfishing, it is important to be a responsible consumer, to
advocate for marine sanctuaries, and to help spread the word. Most people do not know what
happens in the oceans because they are in effect, out of sight and out of mind.
7. Should fishers who harvest fish from a country’s publicly owned waters be required to pay the
government fees for the fish they catch? Explain. If your livelihood depended on commercial
fishing, would you be for or against such fees?
I think that taking fish from publicly owned waters should be applicable for a tax or fee of some
sort. The money could be used for research and/or monitoring purposes. If I was a commercial
fisherman I would want my livelihood to continue. If charging fees meant that the fishing
industry would become more sustainable then I would be for it. The fees paid would be reflected
in higher fish prices and may help regulate the industry and keep fishing families who have been
in the business for many generations from going bankrupt or having to close their operations.
8. Some scientists consider ocean acidification to be one of the most serious environmental and
economic threats that the world faces. How do you contribute to ocean acidification in your daily
life? What are three things you could do to help reduce the threat of ocean acidification?
Contributions to ocean acidification come from the continued use of fossil fuels and anything that
puts CO2 in the atmosphere. Each student’s three things will vary.
Ecological Footprint Question
A fishprint provides a measure of a country’s fish harvest in terms of area. The unit of area used in
fishprint analysis is the global hectare (gha), a unit weighted to reflect the relative ecological productivity
of the area fished. When compared with the fishing area’s sustainable biocapacity, its ability to provide a
stable supply of fish year after year in terms of area, it indicates whether the country’s fishing intensity is
sustainable. The fishprint and biocapacity are calculated using the following formulae:
Fishprint in (gha) = metric tons of fish harvested per year/productivity in metric tons per hectare
X weighting factor.
Biocapacity in (gha) = sustained yield of fish in metric tons per year/productivity in metric tons
per hectare X weighting factor.
Sustaining Aquatic Biodiversity
Global Fishprint and Biocapacity 1950-2000 in Billion Global Hectares
70
60
Billions of GHA
50
40
Fishprint
Biocapacity
30
20
10
0
1950
1960
1970
1980
1990
2000
Year
1. Based on the graph
(a) What is the current status of the global fisheries with respect to sustainability?
(b) In what year did the global fishprint begin exceeding the biological capacity of the world’s
oceans?
(c) By how much did the global fishprint exceed the biological capacity of the world’s oceans in
2000?
2. Assume a country harvests 18 million metric tons of fish annually from an ocean area with an average
productivity of 1.3 metric tons per hectare and a weighting factor of 2.68. What is the annual fishprint of
that country?
3. If biologists determine that this country’s sustained yield of fish is 17 million metric tons per year
(a) What is the country’s sustainable biological capacity?
(b) Is the county’s fishing intensity sustainable?
(c) To what extent, as a percentage, is the country under- or overshooting its biological
capacity?
ANSWERS
1. (a) Currently the global fisheries are greatly overfishing the sustainability of the oceans.
(b) The global fisheries catch or fishprint began to exceed the biological capacity of the oceans in about
1970, and this trend continues today.
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(c) In 2000, the global fishprint exceeded the biological capacity of the world’s oceans by 36 billion
global hectares (gha).
2. The country’s fishprint is 18 million metric tons per year/ 1.3 metric tons per hectare = 13.8 metric tons
X 2.68 = 37.1 global hectares (gha)
3. (a) The country’s sustainable biological capacity is 17 million metric tons per year/1.3 metric tons per
hectare = 13.1 metric tons X 2.68 = 35.0 global hectares (gha)
(b) No, the country’s fishing intensity is not sustainable.
(c) The country is overshooting its biological capacity at a rate of 37.1 gha – 35.0 gha = 2.1 gha /37.1 = 5.6% per
year.
Sustaining Aquatic Biodiversity