What%20Sustains%20Life%20on%20Earth?

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What Sustains Life on Earth?

• Solar energy, the cycling of matter, and gravity
  sustain the earths life.

Figure 3-7
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The Carbon Cycle
Figure 3-27
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The Nitrogen Cycle
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The Phosphorus Cycle
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Populations, Communities, and Ecosystems

• Members of a same species interact in groups
  called populations.
• Populations of different species living and
  interacting in an area form a community.
• A community interacting with its physical
  environment of matter and energy is an ecosystem.

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Ecosystems consist of nonliving (abiotic) and
living (biotic) components. These factors
determine what life can exist in an ecosystem.
Figure 3-10
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Factors That Limit Population Growth

• Availability of matter and energy resources can
  limit the number of organisms in a population
  (zone of tolerance)

Figure 3-11
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Trophic Levels and Laws of Thermodynamics

• First Law of Thermodynamics
• Energy cannot be created or destroyed it can
  change from one form to another
• Ex organisms cannot create energy they need to
  survive- they must capture it from another source
• Focus is on quantity
• Second Law of Thermodynamics
• When energy is converted from one form to
  another, some of it is degraded to heat
• Heat is highly entropic (disorganized)
• Focus is on quality

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Producers Basic Source of All Food

• Most producers capture sunlight to produce
  carbohydrates by photosynthesis
• Chemosynthesis
• Some organisms such as deep ocean bacteria draw
  energy from hydrothermal vents and produce
  carbohydrates from hydrogen sulfide (H2S) gas .

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Consumers Eating and Recycling to Survive

• Consumers (heterotrophs) get their food by eating
  or breaking down all or parts of other organisms
  or their remains.
• Herbivores
• Primary consumers that eat producers
• Carnivores
• Primary consumers eat primary consumers
• Third and higher level consumers carnivores that
  eat carnivores.
• Omnivores
• Feed on both plant and animals.
• Scavengers
• Feed on dead leftovers, lazy hunters.

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Aerobic and Anaerobic Respiration Getting Energy
for Survival

• Organisms break down carbohydrates and other
  organic compounds in their cells to obtain the
  energy they need.
• This is usually done through aerobic (cellular)
  respiration.
• The opposite of photosynthesis

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Aerobic and Anaerobic Respiration Getting Energy
for Survival

• Anaerobic respiration or fermentation
• Some decomposers get energy by breaking down
  glucose (or other organic compounds) in the
  absence of oxygen.
• The end products vary based on the chemical
  reaction
• Methane gas
• Ethyl alcohol
• Acetic acid
• Hydrogen sulfide

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Decomposers and Detrivores

• Decomposers Recycle nutrients in ecosystems.
• Bacteria and fungi
• Detrivores Insects or other scavengers that feed
  on wastes or dead bodies.

Figure 3-13
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ENERGY FLOW IN ECOSYSTEMS

• Food chains and webs show how eaters, the eaten,
  and the decomposed are connected to one another
  in an ecosystem.

Figure 3-17
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Energy Flow in an Ecosystem Losing Energy in
Food Chains and Webs

• Ecological efficiency percentage of useable
  energy transferred as biomass from one trophic
  level to the next. Energy lost as heat.

Figure 3-19
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Productivity of Producers The Rate Is Crucial

• Net primary production (NPP)
• Energy captured through photosynthesis minus the
  energy respired by the producers. The energy
  respired is the energy used for survival and
  stored as biomass.

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• What are natures three most productive and three
  least productive systems?

Figure 3-22
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Biomass Pyramid

• Biomass amount of living matter

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BIODIVERSITY
Figure 3-15
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Why Should We Care About Biodiversity?

• Biodiversity the variety of different species,
  variety of ecosystems, and genetic variability
  within each species.
• Biodiversity provides us with
• Natural Resources (food water, wood, energy, and
  medicines)
• Natural Services (air and water purification,
  soil fertility, waste disposal, pest control)
• Aesthetic pleasure

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Ecosystem Services

• Provisions ecosystems provide goods humans can
  use (lumber, food crops, medicinal plants,
  natural rubber, furs, pharmaceutical drugs)
• Regulating Services ecosystems regulate
  nutrient and hydrological cycles (a lot of carbon
  is removed from atmosphere by rainforests and
  oceans)
• Support Systems pollination of food crops,
  natural pest control services, filter pathogens
  and chemicals from water
• Cultural Services intellectual and aesthetic
  satisfaction
• Resilience rate at which an ecosystem returns
  to its original state after a disturbance (higher
  genetic diversity usually means higher resilience)

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EVOLUTION, NATURAL SELECTION, AND ADAPTATION

• Biological evolution by natural selection
  involves the change in a populations genetic
  makeup through successive generations.
• genetic variability
• Mutations random changes in the structure or
  number of DNA molecules in a cell that can be
  inherited by offspring.

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Natural Selection and Adaptation Leaving More
Offspring With Beneficial Traits

• Three conditions are necessary for biological
  evolution
• Genetic variability, traits must be heritable,
  trait must lead to differential reproduction.
• An adaptive trait is any heritable trait that
  enables an organism to survive through natural
  selection and reproduce better under prevailing
  environmental conditions.

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Coevolution A Biological Arms Race

• Coevolution - Interacting species can engage in a
  back and forth genetic contest in which each
  gains a temporary genetic advantage over the
  other.
• This often happens between predators and prey
  species.

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ECOLOGICAL NICHES AND ADAPTATION

• Each species in an ecosystem has a niche or a
  specific role or way of life.
• Fundamental niche the full potential range of
  physical, chemical, and biological conditions and
  resources a species could theoretically use.
• Realized niche to survive and avoid competition,
  a species usually occupies only part of its
  fundamental niche.

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Generalist and Specialist Species Broad and
Narrow Niches

• Generalist species tolerate a wide range of
  conditions.
• Specialist species can only tolerate a narrow
  range of conditions.

Figure 4-7
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SPECIATION, EXTINCTION, AND BIODIVERSITY

• Speciation A new species can arise when member
  of a population become isolated for a long period
  of time.
• Genetic makeup changes, preventing them from
  producing fertile offspring with the original
  population if reunited.

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Geographic Isolation

• can lead to reproductive isolation, divergence
  of gene pools and speciation.

Figure 4-10
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Species Diversity and Niche Structure Different
Species Playing Different Roles

• Biological communities differ in the types and
  numbers of species they contain and the
  ecological roles those species play.
• Species diversity the number of different
  species it contains (species richness) combined
  with the abundance of individuals within each of
  those species (species evenness).

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TYPES OF SPECIES

• Native those that normally live and thrive in a
  particular community.
• Nonnative species those that migrate,
  deliberately or accidentally introduced into a
  community.

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Indicator Species Biological Smoke Alarms

• Species that serve as early warnings of damage to
  a community or an ecosystem.
• They have such narrow zones of tolerance that
  when they have issues it is a sign that
  something is different from optimum.
• Presence or absence of trout species because they
  are sensitive to temperature and oxygen levels.

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Keystone Species Major Players

• Keystone species help determine the types and
  numbers of other species in a community thereby
  helping to sustain it.

Figures 7-4 and 7-5
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Foundation Species Other Major Players

• Expansion of keystone species category.
• Foundation species can create and enhance
  habitats that can benefit other species in a
  community.
• Wolves in Yellowstone
• Elephants push over, break, or uproot trees,
  creating forest openings promoting grass growth
  for other species to utilize.

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SPECIES INTERACTIONS COMPETITION AND PREDATION

• Species called predators feed on other species
  called prey.
• Organisms use their senses their senses to locate
  objects and prey and to attract pollinators and
  mates.
• Some predators are fast enough to catch their
  prey, some hide and lie in wait, and some inject
  chemicals to paralyze their prey.

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SPECIES INTERACTIONS PARASITISM, MUTUALISM, AND
COMMENSALIM

• Parasitism (and -) occurs when one species feeds
  on part of another organism.
• In mutualism ( and ), two species interact in a
  way that benefits both.
• Commensalism ( and o) is an interaction that
  benefits one species but has little, if any,
  effect on the other species.

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Parasitism ( and -) Sponging Off of Others

• Although parasites can harm their hosts, they can
  promote community biodiversity.
• Some parasites live in host (micororganisms,
  tapeworms).
• Some parasites live outside host (fleas, ticks,
  mistletoe plants, sea lampreys).
• Some have little contact with host (dump-nesting
  birds like cowbirds, some duck species)

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Commensalism ( and o) Using without Harming

• Some species interact in a way that helps one
  species but has little or no effect on the other.

Figure 7-10
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Competition (- and -)

• In competition they both theoretically loose. A
  community interaction where there is a fight for
  food, territory, or mates. Energy is lost by both
  in the struggle. Interspecific and Intraspecific
  competition.

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Competition Reduction StrategyResource
Partitioning

• Each species minimizes competition with the
  others for food by spending at least half its
  feeding time in a distinct portion of the spruce
  tree and by consuming somewhat different insect
  species.

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Specialized Feeding Niches

• Resource partitioning reduces competition and
  allows sharing of limited resources.

Figure 4-8
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Ecotones on Land

• Shares many of the species and characteristics of
  both ecosystems
• May also include unique conditions that support
  distinctive plant and animal species

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Terrestrial-to-Aquatic-System Ecotone

• Shares many of the species and characteristics of
  both ecosystems
• May also include unique conditions that support
  distinctive plant and animal species

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POPULATION DYNAMICS AND CARRYING CAPACITY

• Most populations live in clumps although other
  patterns occur based on resource distribution.

Figure 8-2
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Exponential and Logistic Population Growth
J-Curves and S-Curves

• Populations grow rapidly with ample resources,
  but as resources become limited, its growth rate
  slows and levels off.

Figure 8-4
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Reproductive Patterns

• r-selected species tend to be opportunists
  (generalist) while K-selected species tend to be
  competitors (specialist).

Figure 8-10
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SPECIES EXTINCTION

• Species can become extinct
• Locally A species is no longer found in an area
  it once inhabited but is still found elsewhere in
  the world.
• Ecologically Occurs when so few members of a
  species are left they no longer play its
  ecological role.
• Globally (biologically) Species is no longer
  found on the earth.

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Global Extinction

• Some animals have become prematurely extinct
  because of human activities.

Figure 11-2
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Endangered and Threatened Species Ecological
Smoke Alarms

• Endangered species so few individual survivors
  that it could soon become extinct.
• Threatened species still abundant in its natural
  range but is likely to become endangered in the
  near future.

Figure 11-3
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SPECIES EXTINCTION

• Some species have characteristics that make them
  vulnerable to ecological and biological
  extinction.

Figure 11-4
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SPECIES EXTINCTION

• Scientists use measurements and models to
  estimate extinction rates.
• The International Union for the Conservation of
  Nature and Natural Resources (IUCN) publishes an
  annual Red List, listing the worlds threatened
  species.
• The 2004 Red List contains 15,589 species at risk
  for extinction.
• For the United States US Fish and Wildlife Dep.
  Lists / Delists species and enforces protection.

Figure 11-5
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HABITAT LOSS, DEGRADATION, AND FRAGMENTATION

• Conservation biologists summarize the most
  important causes of premature extinction as
  HIPPCO
• Habitat destruction, degradation, and
  fragmentation
• Invasive species
• Population growth (Human)
• Pollution
• Climate Change
• Overharvest

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HABITAT LOSS, DEGRADATION, AND FRAGMENTATION

• The greatest threat to a species is the loss,
  degradation, and fragmentation of where it lives.

Figure 11-7
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HABITAT LOSS, DEGRADATION, AND FRAGMENTATION

• Reduction in ranges of four wildlife species,
  mostly due to habitat loss and overharvest.

Figure 11-8
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Case Study A Disturbing Message from the Birds

• The majority of the worlds bird species are
  found in South America.
• Threatened with habitat loss and invasive species.

Figure 11-10
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INVASIVE SPECIES

• A nonnative species that dominates or outcompetes
  native species. Some are good, just not in the
  nonnative area. They can provide us with food,
  medicine, and other benefits but a few can wipe
  out native species, disrupt ecosystems, and cause
  large economic losses.

Kudzu vine was introduced in the southeastern
U.S. to control erosion. It has taken over native
species habitats.
Figure 11-A
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INVASIVE SPECIES

• US spent 1.2 billion in 2007
• Globally 1.4 trillion

Figure 11-11
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Cowbird
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INVASIVE SPECIES

• The Argentina fire ant was introduced to Mobile,
  Alabama in 1932 from South America.
• Most probably from ships.
• No natural predators.

Figure 11-12
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Introduced Species Rabbits in Australia

• Introduced into Australia from England in 1859
• No natural enemies rabbit population exploded
• Overabundant herbivore population devastated
  natural vegetation (see Fig. 4-11 in text).
• Using disease as control measure why will this
  procedure fail in the long-term?

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Zebra Mussels
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Water Hyacinths
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Characteristics of Successful Invader Species
Characteristics of Ecosystems Vulnerable to
Invader Species
Climate similar to habitat of invader
Absence of predators on invading species Early
successional systems Low diversity of
native species Absence of fire Disturbed by
human activities
High reproductive rate, short generation
time (r-selected species) Pioneer species
Long lived High dispersal rate Release
growth-inhibiting chemicals into soil
Generalists High genetic variability
Fig. 11-13, p. 236
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Pollution

• Each year pesticides
• Kill about 1/5th of the U.S. honeybee colonies.
• 67 million birds.
• 6 -14 million fish.
• Threaten 1/5th of the U.S.s endangered and
  threatened species.

Example of biomagnification of DDT in an aquatic
food chain.
Figure 11-15
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Effects of climate change on Biodiversity
Winners and Losers

• Possible effects of climate change on the
  geographic range of beech trees based on
  ecological evidence and computer models.

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OVEREXPLOITATION

• Poaching - Some protected species are killed for
  their valuable parts or are sold live to
  collectors.
• Killing predators and pests that bother us or
  cause economic losses threatens some species with
  premature extinction.
• Legal and illegal trade in wildlife species used
  as pets or for decorative purposes threatens some
  species with extinction.

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OVEREXPLOITATION

• Rhinoceros are often killed for their horns and
  sold illegally on the black market for decorative
  and medicinal purposes.

Figure 11-16
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Case Study The U.S. Endangered Species Act

• One of the worlds most far-reaching and
  controversial environmental laws is the 1973 U.S.
  Endangered Species Act (ESA).
• ESA forbids federal agencies (besides defense
  department) to carry out / fund projects that
  would jeopardize an endangered species.
• ESA makes it illegal for Americans to engage in
  commerce associated with or hunt / kill / collect
  endangered or threatened species.

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PROTECTING WILD SPECIES LEGAL AND ECONOMIC
APPROACHES

• International treaties have helped reduce the
  international trade of endangered and threatened
  species, but enforcement is difficult.
• One of the most powerful is the 1975 Convention
  on International Trade of Endangered Species
  (CITES).
• Signed by 169 countries, lists 900 species that
  cannot be commercially traded.

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International Biodiversity Hotspots
60 of the biodiversity is located on just 1.4
of the Earths land surface.
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RECONCILIATION ECOLOGY

• Reconciliation ecology involves finding ways to
  share places we dominate with other species.
• Replacing monoculture grasses with native
  species.
• Maintaining habitats for insect eating bats can
  keep down unwanted insects.
• Reduction and elimination of pesticides to
  protect non-target organisms (such as vital
  insect pollinators).

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AQUATIC BIODIVERSITY

• We know fairly little about the biodiversity of
  the worlds marine and freshwater systems.
• The greatest marine biodiversity occurs in coral
  reefs, estuaries and the deep ocean floor.
• Biodiversity is higher near the coast and surface
  because of habitat and food source variety.
• The worlds marine and freshwater systems provide
  important ecological and economic services.

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Population Growth and Pollution

• Each year plastic items dumped from ships and
  left as litter on beaches threaten marine life.

Figure 12-3
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Overfishing and Extinction Gone Fishing, Fish
Gone

• About 75 of the worlds commercially valuable
  marine fish species are over fished or fished
  near their sustainable limits.
• Big fish are becoming scarce.
• Smaller fish are next.
• We throw away 30 of the fish we catch.
• We needlessly kill sea mammals and birds.

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Trawler fishing
Fish farming in cage
Spotter airplane
Sonar
Purse-seine fishing
Trawl flap
Trawl lines
Fish school
Trawl bag
Drift-net fishing
Long line fishing
Buoy
Float
Lines with hooks
Deep sea aquaculture cage
Fish caught by gills
Fig. 12-A, p. 255
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Why is it Difficult to Protect Aquatic
Biodiversity?

• Rapid increasing human impacts, the invisibility
  of problems, citizen unawareness, and lack of
  legal jurisdiction hinder protection of aquatic
  biodiversity.
• Human ecological footprint is expanding.
• Much of the damage to oceans is not visible to
  most people.
• Many people incorrectly view the oceans as an
  inexhaustible resource.

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PROTECTING AND SUSTAINING MARINE BIODIVERSITY

• Laws, international treaties, and education can
  help reduce the premature extinction of marine
  species.
• Since 1989 the U.S. government has required
  offshore shrimp trawlers to use turtle exclusion
  devices (T.E.D.s).
• Sea turtle tourism brings in almost three times
  as much money as the sale of turtle products.

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PROTECTING AND SUSTAINING MARINE BIODIVERSITY

• Fully protected marine reserves make up less than
  0.3 of the worlds ocean area.
• Studies show that fish populations double, size
  grows by almost a third, reproduction triples and
  species diversity increases by almost one fourth.
• Some communities work together to develop
  integrated plans for managing their coastal areas.

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Solutions
Managing Fisheries
Fishery Regulations Set catch limits well below
the maximum sustainable yield Improve monitoring
and enforcement of regulations
Bycatch Use wide-meshed nets to allow escape of
smaller fish Use net escape devices for sea
birds and sea turtles Ban throwing edible and
marketable fish back into the sea
Economic Approaches Sharply reduce or eliminate
fishing subsidies Charge fees for harvesting
fish and shellfish from publicly owned offshore
waters Certify sustainable fisheries
Aquaculture Restrict coastal locations for fish
farms Control pollution more strictly Depend
more on herbivorous fish species
Protected Areas Establish no-fishing
areas Establish more marine protected
areas Rely more on integrated coastal management
Nonnative Invasions Kill organisms in ship
ballast water Filter organisms from ship ballast
water Dump ballast water far at sea and replace
with deep-sea water
Consumer Information Label sustainably harvested
fish Publicize overfished and threatened species
Fig. 12-7, p. 261