Transcript Chapter 17 - Marine Resources

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►Resource Classification
►Nonrenewable Resources
►Renewable Resources
►Submerged Cultural Resources
►Biological Resources – Marine Mammals
►Biological Resources – Algae, Aquaculture and Medicine
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►Biological Resources – Fish
►The State of the World’s Fisheries – A Bleak Picture
►Commercial Fishing
►Who Owns the Sea?
►Biodiversity and the Future
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Chapter 17 Pages 17-3 to 17-4
Resource Classification
Resource Classification
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 Because there is a broad range of
marine resources, it is best to
begin by classifying them into
different areas.
 Two common categories are
renewable and nonrenewable
resources and physical and
biological resources.
Chapter 17 Pages 17-3 to 17-4
Resource Classification
Resource Classification
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Resource Classification
Chapter 17 Pages 17-3 to 17-4
Resource Classification
 Biological resources are those that involve
bioproductivity, such as fisheries and kelp
harvesting.
 Physical resources don’t involve biological
processes. These include minerals, energy
production, and recreation.
Kelp Harvesting
in
Southern California
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Resource Classification
Chapter 17 Pages 17-3 to 17-4
Resource Classification
 Renewable resources are those that growing
organisms, sunlight, or other processes naturally
replace.
 Nonrenewable resources are those that natural
processes don’t replace, or that do so at such a slow
rate that they’re not replenished in a human lifespan.
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Chapter 17 Pages 17-3 to 17-4
Resource Classification
Resource Classification
 Many physical resources, such as oil and natural gas, are
nonrenewable.
 Some, such as wave energy, are renewable because the
sun replenishes the energy source daily.
 People tend to think of biological resources as renewable, and
in many cases they are.
 However, while most marine biological resources are
potentially renewable, most are effectively nonrenewable.
 This happens when a fishery takes a species from the ocean
faster than it can reproduce to maintain its population.
 Whaling and commercial fishing are two of many examples.
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Chapter 17 Pages 17-5 to 17-14
Nonrenewable Resources
Nonrenewable Resources
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Chapter 17 Pages 17-5 to 17-8
Nonrenewable Resources
Energy
Petroleum & Natural Gas
 About one third of the world’s crude oil and about a
quarter of the natural gas come from offshore
sources.
 Crude oil is a complex mix of thousands of different
compounds.
 Mostly hydrocarbons, which consist of carbon and
hydrogen chains.
 Hydrocarbons are the source of chemical energy
from which refineries distill gasoline, diesel,
kerosene, and other fuels.
 Natural gas, also called methane
(CH4), is a gaseous hydrocarbon.
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Energy
Petroleum & Natural Gas
Nonrenewable Resources
Chapter 17 Pages 17-5 to 17-8
 Geologists find petroleum and natural gas in marine
and terrestrial sediments.
 Scientists conclude that petroleum and natural gas
form from the remains of primarily marine
organisms.
Platform Mars
in the Gulf of
Mexico
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Energy
Nonrenewable Resources
Chapter 17 Pages 17-5 to 17-8
Petroleum & Natural Gas
 After these organisms die, they amass in
depressions with little water motion, low oxygen,
and few scavenging organisms.
 Anaerobic bacteria break down the organic matter
into simpler organic compounds.
 As time passes, sediments accumulate on top of
these compounds until they’re under high
pressure and high temperature.
 The compounds continue to undergo conversion
into hydrocarbons - can take millions of years.
 This completes the transition of these organisms
into crude oil.
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Energy
Nonrenewable Resources
Chapter 17 Pages 17-5 to 17-8
Petroleum & Natural Gas
 Scientists have concluded that this same process results in
methane (natural gas–CH4) along with petroleum.
 In the case of methane the insoluble compounds progress
from petroleum to methane when the process continues for
longer periods, or at a higher temperature.
 This explains why geologists have found few oil deposits
below 3,000 meters (9,800 feet), and only natural gas
deeper than 7,000 meters (23,000 feet).
 The pressure and temperature are so high that only methane
forms.
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Energy
Nonrenewable Resources
Chapter 17 Pages 17-5 to 17-8
Petroleum & Natural Gas
 Oceanographers study sediments with seismic
instruments.
 By studying how sound waves travel and echo
within sediment, they can determine variations in
density and composition.
 This method applies well to the search for oil
because it is less dense than surrounding
sediments.
 The physical characteristics of the rock
surrounding oil and natural gas are important
because they determine where the oil or gas
collects.
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Energy
Chapter 17 Pages 17-5 to 17-8
Nonrenewable Resources
Petroleum & Natural Gas
 Hydrocarbons form surrounded by source rock.
 They don’t necessarily stay there, however, and
may travel through porous sediments lying over it.
 When hydrocarbons reach rock that they can’t
penetrate, called reserve rock, they collect in the
spaces underneath it, allowing the oil or gas to
pool. This is called an oil or gas reserve.
 Sound waves detect the reserves as low-density
pockets in the reserve rock.
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Energy
Petroleum & Natural Gas
Nonrenewable Resources
Chapter 17 Pages 17-5 to 17-8
Drilling For Oil
and Gas
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Energy
Chapter 17 Pages 17-5 to 17-8
Nonrenewable Resources
Petroleum & Natural Gas
 Oil companies extract petroleum and natural gas
by drilling through sediment and rock into the
reserve.
 Despite the cost and complexity, however, offshore
drilling continues to grow to meet the demand for oil
and gas.
 One of the newest deep water
platforms is Platform Mars.
 Today, oil companies are taking
more risks and drilling ever
deeper wells as their shallower
wells run dry.
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Energy
Chapter 17 Pages 17-8 to 17-9
Nonrenewable Resources
Methane Hydrates
 Methane hydrates is another form of nonrenewable
marine energy source.
 They are ice crystals containing methane found on
the continental slope.
 They consist of frozen water molecules that create
a cage within sediment.
 Each of these cages holds a single methane gas
molecule.
 When you bring methane hydrates to the surface,
the ice melts, releasing the methane.
 You can literally light a match and ignite the
methane emerging from the sediments.
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Energy
Chapter 17 Pages 17-8 to 17-9
Nonrenewable Resources
Methane Hydrates
 Scientists are still determining exactly how methane
hydrates form.
 Worldwide, more than 11,320 million trillion liters/400
million trillion cubic feet of methane
are thought to exist in
methane hydrates.
 That’s enough natural gas to
supply the world’s needs
for centuries.
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Energy
Chapter 17 Pages 17-8 to 17-9
Nonrenewable Resources
Methane Hydrates
 Despite this tremendous energy resource potential,
currently no one uses methane hydrates as fuel.
 Very expensive to recover them - relatively
dangerous to handle.
 Technologies for handling methane hydrates
are being developed - there are challenges.
 Methane is a greenhouse gas - they could be a
problem if changing sea temperatures or the effects
of mining caused a sudden release.
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Chapter 17 Pages 17-8 to 17-9
Nonrenewable Resources
Energy
Methane Hydrates
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Chapter 17 Pages 17-10 to 17-13
Nonrenewable Resources
Salts and Minerals
 Ferromanganese Nodules. Ferromanganese
nodules commonly form around shark teeth and
volcanic fragments.
 Magnesium Compounds. Magnesium is a strong,
lightweight metal essential for
aerospace construction and
other structural applications.
Third most abundant element
in seawater.
 Salts. Evaporites are the salts
left behind when seawater evaporates.
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 Phosphorite. Phosphorite deposits are
the remains of marine organisms that
live in areas with extensive upwelling.
 Marine Muds and Metals.
Hydrothermal vents play a role in
supporting chemosynthetic ecosystems
and maintaining seawater chemistry.
Chapter 17 Pages 17-10 to 17-13
Nonrenewable Resources
Salts and Minerals
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Gravel and Sand
Chapter 17 Page 17-13
Nonrenewable Resources
 At present, gravel and sand are second only to gas
and oil in their annual economic value.
Mining Sand and Gravel.
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Chapter 17 Pages 17-15 to 17-21
Renewable Resources
Renewable Resources
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Energy
Chapter 17 Pages 17-15 to 17-16
Renewable Resources
 Although we customarily think of oil and natural gas
when we think of energy from marine resources, the
sea offers renewable energy options.
 Wave energy.
 Tide energy.
 Thermal gradient technology.
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Energy
Chapter 17 Pages 17-15 to 17-21
Renewable Resources
 Of these three renewable energy resources, none are
really commercially feasible at present.
 Tidal power seems the most feasible.
 Tidal energy has environmental concerns.
 Thermal gradient technology has been tried
experimentally but has largely been abandoned
because it has low efficiency.
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Energy
Chapter 17 Pages 17-15 to 17-21
Renewable Resources
Harnessing Wave
Energy
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Ocean
Thermal
Energy
Conversion
Chapter 17 Pages 17-15 to 17-21
Renewable Resources
Energy
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Chapter 17 Pages 17-17 to 17-18
Renewable Resources
Fresh Water
 It may seem odd to think of fresh water as a marine resource,
but it certainly is.
 Natural fresh water is not always in ample supply.
 The single most important factor that determines how many
people can live in a given area is the availability of fresh
water.
 Extracting fresh water from seawater involves desalinization—
the removal of dissolved salts.
 Distillation is the process of evaporating seawater and capturing
the water vapor to leave the salts behind.
 About a quarter of all desalinization uses reverse osmosis.
 There are inventors working on low-cost desalinization
technologies.
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Chapter 17 Pages 17-18 to 17-20
Renewable Resources
Nonextractive Resources
 There’s a class of resources that you may not think of as
resources, but they most certainly are. Nonextractive
resources are those we obtain from the sea without removing
anything from the sea.
 Therefore, they are renewable because there’s nothing that
needs renewing.
 The three most conspicuous uses of the sea are for transport
shipping, projection of state power and recreation.
 These are physical resources in that they involve the
physical aspects of the sea.
 Recreation can also be considered a biological resource in
that many recreations involve organisms within the sea.
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Chapter 17 Pages 17-18 to 17-20
Renewable Resources
Nonextractive Resources
 Sea Transport Shipping:
 History shows that the ocean is
important as a corridor for shipping.
 Sea transport has been vital for
hundreds of years and remains so.
 At one time, cargo ships needed weeks
to load and unload.
 After World War II, the invention of the
cargo container revolutionized sea
transport shipping.
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Nonextractive Resources
Chapter 17 Pages 17-18 to 17-20
Renewable Resources
 Projection of state military power.
 Recreation.
 Ecotourism.
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Chapter 17 Pages 17-22 to 17-23
Submerged Cultural Resources
Submerged Cultural Resources
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Chapter 17 Page 17-22
Submerged Cultural Resources
A Definition – Submerged Cultural
Resources
 Submerged cultural resources can be:
 Shipwrecks.
 Submerged settlements.
 Burial and disposal sites.
 Underwater areas with artifacts left by
prehistoric and historic cultures.
 In addition to the ocean, underwater sinkholes and
caves are often rich in archaeology.
 Shipwrecks give archaeologists with information
about how people lived, died and constructed their
ships.
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Chapter 17 Page 17-23
Submerged Cultural Resources
Protecting Submerged Cultural Resources
 Preserving the scientific and historical integrity of
submerged cultural resources is important to
protect what scientists learn from them.
 Removing or even just disturbing the contents of
sites diminishes the information archaeologists
can learn from them.
 Submerged cultural resources are often protected.
 Most underwater archaeologists approve of divers
visiting sites in a respectful way.
 Often, national and international laws protect
submerged cultural sites to keep them from being
looted or defaced.
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Chapter 17 Pages 17-24 to 17-28
Biological Resources - Marine Mammals
Biological Resources - Marine Mammals
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Whales
Chapter 17 Pages 17-24 to 17-26
Biological Resources - Marine Mammals
 Whaling dates back at least 2,000 years.
 While the Japanese killed whales for the meat, the
Europeans were primarily interested in blubber.
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Chapter 17 Pages 17-24 to 17-26
Biological Resources - Marine Mammals
Whales
 Until 1868, primitive technology made whaling dangerous and
difficult.
 Harpoons were little more than heavy spears hurled from
small longshore boats.
 The wounded whale would drag the boat (or boats) at high
speed in what came to be called a Nantucket sleigh ride,
named for the whaling port of Nantucket, Massachusetts.
 Often the whale towed the longshore boat for hours before it
became exhausted enough to be killed.
 With these crude methods, comparatively few whales
could be taken and whale populations remained stable.
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Whales
Chapter 17 Pages 17-24 to 17-26
Biological Resources - Marine Mammals
 Everything changed in 1868 with the invention of the
modern harpoon gun.
 Instead of hand-thrown spears, the modern whale harpoon
launches from a gun and explodes on impact inside the
whale.
 Besides being a more damaging weapon, the modern
harpoon can be launched from a steamship.
 This allowed them to harvest fast
whales.
 Attacking and killing a whale went
from taking hours to taking minutes.
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 As with commercial fishing, whalers continued to use
new technologies.
 By the late 1960s, whaling fleets had spotter
airplanes looking for pods from the air.
 They used sonar to track whales trying to escape
in the depths.
Chapter 17 Pages 17-24 to 17-26
Biological Resources - Marine Mammals
Whales
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Chapter 17 Pages 17-24 to 17-26
Biological Resources - Marine Mammals
Whales
 International whaling has been so successful that
whale populations plunged during the 20th
century.
 From an estimated population of 4.4 million in
1900, today the estimated population is around 1
million.
 Eight of the 11 great whale species became
commercially extinct. However, whalers often still
took them if they happened across them.
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Chapter 17 Pages 17-24 to 17-26
Biological Resources - Marine Mammals
Whales
 With whale populations already dwindling by World War II, in
1946 the International Whaling Commission (IWC) formed to set
quotas in an effort to stay within maximum sustainable yields.
 Quotas were too high and populations continued to fall.
 As international attention focused on the plight of the whales,
many nonwhaling nations joined the IWC.
 Called for indefinite moratorium on whaling; effective in
1986.
 The results of the moratorium provide a lesson in species
recovery.
 Several major species recovered.
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Whales
Biological Resources - Marine Mammals
Chapter 17 Pages 17-24 to 17-26
 The lesson appears to be that, given a chance, a species can
recover. However, if ending commercial pressure takes too long,
a species may not make it and continue into extinction.
 Despite the moratorium and the continued low population
levels, whaling still continues.
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Chapter 17 Page 17-27
Biological Resources - Marine Mammals
Other Cetaceans
 While large whales tend to be the focus in whaling, far more
small cetaceans get killed.
 IWC doesn’t protect dolphins.
 Several species face immediate danger.
 In some countries, dolphin costs less than chicken or beef.
 Another threat to dolphins and small whales is they are caught
in nets set by commercial fishers.
 Today US tuna fishers and foreign importers must comply with
dolphin safe fishing techniques that reduce dolphin kills.
 It is worth noting that today neither whales nor
small cetaceans provide any material that’s
not available from some other source.
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Chapter 17 Pages 17-27 to 17-28
Biological Resources - Marine Mammals
Seals and Sea Lions
 Historically, seals and sea lions have been biological
resources exploited for their fur and for food.
 At the turn of the 19th century, fur seal populations
were so decimated that Russia, Japan, Great Britain
and the US entered into the Fur Seal Treaty of 1911,
which remained in effect for 30 years.
 It was the first international treaty involving several
countries that dealt with wildlife conservation and
was a role model for future treaties.
 Within five years, the population rebounded and
protection was extended in 1966.
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Chapter 17 Pages 17-27 to 17-28
Biological Resources - Marine Mammals
Seals and Sea Lions
 Although the marine mammal fur trade no longer
exists in the US due to the Marine Mammal
Protection Act and consumer pressure, worldwide up
to half a million of these marine mammals die for their
fur annually.
 The most famous fur hunt is the harp seal hunt,
which takes place on the Canadian coast on the
Labrador Sea.
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Chapter 17 Pages 17-29 to 17-32
Biological Resources - Algae, Aquaculture, and Medicine
Biological Resources-Algae,
Aquaculture, and Medicine
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 Animals aren’t the only biological resources people
take from the sea.
 Marine algae is another resource used as food.
 Seaweeds and algae make up 10% of the
Japanese diet; much of this is red algae nori.
 Nori is the most-consumed alga in the world and is
often served with sushi.
Chapter 17 Page 17-29
Biological Resources - Algae, Aquaculture, and Medicine
Algae
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Chapter 17 Page 17-29
Biological Resources - Algae, Aquaculture, and Medicine
Algae
 You may be surprised to learn how much algae
you consume.
 Algin is useful in food processing and other
applications.
 Used in salad dressing, ice cream, beer and wine.
 You also find algin in paint and abrasives.
 With widespread applications in food and chemical
processes, industry uses nearly $250 million worth
of algin annually.
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Chapter 17 Pages 17-29 to 17-31
Biological Resources - Algae, Aquaculture, and Medicine
Farming the Sea
 Commercial fishing is comparable to terrestrial
hunting and gathering.
 It entails living off what happens to grow naturally.
More recently, aquaculture has come onto the
scene.
 Aquaculture is comparable to terrestrial farming
and ranching. It uses farming techniques to grow
and harvest aquatic organisms.
 Mariculture is aquaculture specific to the marine
environment.
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Biological Resources - Algae, Aquaculture, and Medicine
Chapter 17 Pages 17-29 to 17-31
Farming the Sea
 The growth trend in aquaculture is steeply upward.
 According to the Food and Agriculture Organization, the
total contribution of aquaculture to global supplies of
fish, crustaceans, mollusks and other aquatic animals
grew from 4% in 1970 to 27% in 2000 and 32% in 2004.
 In 2004, aquaculture produced more than 60 million tons of
fish, seafood, and other biological resources. The estimated
value was about $70 million.
 China alone accounts for about 70% of the total quantity of
aquaculture production.
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 Today, about 30% of the world’s seafood comes
from aquaculture.
 Aquaculture may sound like the solution to
overfishing, but it’s not without its problems.
Chapter 17 Pages 17-29 to 17-31
Biological Resources - Algae, Aquaculture, and Medicine
Farming the Sea
Sea Farming
Aquaculture
Pens
Salmon
Aquaculture
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Biological Resources - Algae, Aquaculture, and Medicine
Chapter 17 Pages 17-29 to 17-31
Farming the Sea
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Biological Resources - Algae, Aquaculture, and Medicine
Chapter 17 Pages 17-29 to 17-31
Farming the Sea
 Aquaculture problems include:
 Fish meal made from wild-caught fish is used in
aquaculture.
 Only about 10% of the biomass from one level
makes it to the next.
 Disease due to close quarter living.
 Concentrated waste from raised animals.
 Consumes resources that could be used by wild
animals.
 Genetic problems.
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Chapter 17 Pages 17-31 to 17-32
Biological Resources - Algae, Aquaculture, and Medicine
New Medicines from the Ocean
 About half of the drugs available to modern medicine
come from nature.
 They’re either natural substances or synthesized
from natural substances, including those found in
the sea.
 Marine scientists estimate that we’ve barely
scratched the surface when it comes to identifying
organisms with potential pharmacological
importance.
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Chapter 17 Pages 17-31 to 17-32
Biological Resources - Algae, Aquaculture, and Medicine
New Medicines from the Ocean
 The search for organisms with pharmacological
or other chemical benefits is called
bioprospecting.
 Is important in the development of new drugs
because it is in nature that chemists often find new
ways to fight disease.
 The potential exists for a wide range of drugs that
combat viruses, inflammation, cancer, heart
disease, AIDS/HIV, and others.
 Even insecticides and a new class
of steroids have been found in
sea organisms.
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Chapter 17 Pages 17-31 to 17-32
Biological Resources - Algae, Aquaculture, and Medicine
New Medicines from the Ocean
 So as not to destroy natural reefs while
bioprospecting, marine scientists are examining the
possibility of harvesting marine organisms for
possible drugs from artificial reefs – like shipwrecks
and oil platforms.
 Biosprospecting can only continue with a healthy sea.
 We could accidentally cause the extinction of the
organism that holds the cure to the disease that
you or someone you love has.
 This is a personal reason everyone has to
preserve a healthy ocean.
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Chapter 17 Pages 17-33 to 17-39
Biological Resources - Fish
Biological Resources - Fish
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Chapter 17 Pages 17-33 to 17-34
Biological Resources - Fish
Fisheries for Food and Industry
 Compared to terrestrial foods, seafood in its many
forms seems a minor contribution to the human diet.
 Worldwide, seafood accounts for only about 4% of
what people eat.
 On the other hand, it accounts for about 18%
of the protein we eat - 15% consumed directly
as seafood and about 3% indirectly through
fish meal and other seafood byproducts fed to
livestock.
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Chapter 17 Pages 17-33 to 17-34
Biological Resources - Fish
Fisheries for Food and Industry
 The amount of seafood consumed varies by nation
and culture.
 About 89% of world’s wild-caught fish comes from
the ocean, with the rest coming from freshwater
sources.
 For some small island developing states, seafood
provides more than 50% of people’s annual
protein intake.
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 Commercial fishing targets both pelagic and
groundfish.
 Pelagic fish live in the open water column.
 Groundfish are benthic, living on or near the sea
bottom.
 Yet of all the species in the sea, only about 500
make up the vast majority of the catch.
Chapter 17 Pages 17-33 to 17-34
Biological Resources - Fish
Fisheries for Food and Industry
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Chapter 17 Pages 17-33 to 17-34
Biological Resources - Fish
Fisheries for Food and Industry
 Commercially important fish are found primarily in
two places: the waters of the continental shelves
and a few offshore regions with abundant
upwelling.
 The reason is that most of the ocean has relatively
low bioproductivity.
 The continental shelves and the upwelling regions
have high productivity because of the ample
supply of nutrients and sunlight.
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Chapter 17 Pages 17-33 to 17-34
Biological Resources - Fish
Fisheries for Food and Industry
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Chapter 17 Pages 17-33 to 17-34
Biological Resources - Fish
Fisheries for Food and Industry
 In 2005, the total world fisheries catch and aquaculture
combined production was an estimated 142 million metric tons.
 This was made up of inland (freshwater) capture and
aquaculture production as well as marine capture and
aquaculture.
 The total amount of wild fish captured from the ocean in
2005 was 84 million metric tons.
 Of the total fisheries production, 108 million metric tons was
used for direct human production and 34 million metric tons
was used for non-food purposes.
 Non-food: 1) fish protein concentrate, 2) fish oil used in food
products, cosmetics and paint.
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Fisheries for Food and Industry
Chapter 17 Pages 17-33 to 17-34
Biological Resources - Fish
 Catching fish for purposes other than direct
human consumption is called reduction fishing.
 In 1950, reduction fisheries accounted for only
about 10% of commercial fishing.
 Today, about one-quarter of the world commercial
fish catch is used for reduction.
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Chapter 17 Pages 17-35 to 17-37
Biological Resources - Fish
Trends in the Worldwide
Commercial Fish Catch
 About a billion people rely on fish as their primary
protein source.
 Worldwide commercial fishing and fishing related
activities employ about 15 million people directly.
 This number does not include people who catch
fish in small quantities for their own consumption.
 Commercial fishing is a physically demanding and
dangerous occupation.
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Chapter 17 Pages 17-35 to 17-37
Biological Resources - Fish
Trends in the Worldwide
Commercial Fish Catch
 In addition to those directly involved in commercial
fishing, another 200 million people have jobs related
to commercial fish processing or distribution.
 By the end of 2004, the world’s fishing fleet was
made up of 4 million vessels.
 The most modern fleets catch fish using scout
planes, satellite-based sensors, current profilers,
sonar, and other technologies.
 Huge factory ships follow many of these fleets,
taking and processing the catch so it’s filleted and
frozen before reaching shore.
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Chapter 17 Pages 17-35 to 17-37
Biological Resources - Fish
Trends in the Worldwide
Commercial Fish Catch
 In 1967 a Commission on Marine Science
Engineering and Resources was appointed to
investigate current and future US coastal and ocean
resources.
 Released its report in 1969 entitled “Our Nations
and the Sea: A Plan for National Action.”
 Report said it would be realistic – even
conservative – to expect to be able to harvest
between 400 and 500 million metric tons of fish
annually.
 This suggests that at the time, we still considered
the ocean’s resources almost limitless.
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Biological Resources - Fish
Chapter 17 Pages 17-35 to 17-37
Trends in the Worldwide
Commercial Fish Catch
 By 1989, the annual catch reached 86 million metric tons and
has held about level at between 70 to 85 million metric tons ever
since.
 In 2005, the FAO estimated that about half the commercially
targeted fish stocks were fully exploited, and about a
quarter were overexploited, depleted or recovering from
depletion.
 Its 2006 report confirmed earlier observations that the maximum
capacity of wild capture fisheries from the ocean has been
reached.
 Instead of reaching the 500 million metric ton catch level
estimated in 1967, commercial fishing from the ocean was
already nearing the probable maximum output.
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Biological Resources - Fish
Chapter 17 Pages 17-35 to 17-37
Trends in the Worldwide
Commercial Fish Catch
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Biological Resources - Fish
Chapter 17 Pages 17-35 to 17-37
Trends in the Worldwide
Commercial Fish Catch
 Many researchers and scientists have their doubts about the
accuracies of reported catch numbers.
 As fish stocks decline, overfishing causes shifts in the fish that
are caught.
 Average size of the fish caught declines.
 Leads to the collapse of the target fish populations - targets
fish previously considered unappealing for human
consumption.
 This is called fishing down the food web.
 Bycatch – the catching of non-target species of fish, birds
and turtles – has resulted in millions of tons of fish being
dumped or discarded at sea. Bycatch is not included in the
fishing statistics.
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Biological Resources - Fish
Chapter 17 Pages 17-35 to 17-37
Trends in the Worldwide
Commercial Fish Catch
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Chapter 17 Pages 17-39 to 17-44
The State of the World’s Fisheries - A Bleak Picture
The State of the World’s Fisheries –
A Bleak Picture
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Chapter 17 Pages 17-39 to 17-40
The State of the World’s Fisheries - A Bleak Picture
Maximum Sustainable Yield, Overfishing
and Ecosystem-Based Management
 Until the 20th century, people believed that the sea
was an infinite resource.
 Today, however, a limitless sea is a myth.
 Technology and rising demand make it possible to
exhaust biological resources.
 We can catch fish and other organisms more
quickly than they can reproduce.
 Given this problem and rising demand, the role of
global fisheries management is to prevent the day
coming when there will be nothing to catch.
 Many fisheries scientists think that, unfortunately,
we’re not off to a very good start.
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Chapter 17 Pages 17-39 to 17-40
The State of the World’s Fisheries - A Bleak Picture
Maximum Sustainable Yield, Overfishing
and Ecosystem-Based Management
 The concept of maximum sustainable yield lies at
the heart of fisheries management.
 Maximum sustainable yield is the greatest
yield (catch) of a target species that fisheries
can take without jeopardizing future catches.
 Overfishing occurs when the quantity of fish taken
exceeds the amount of fish that can be resupplied
by the growth and reproduction of the remaining
population.
 This is what has happened to the cod fishery off
the north Atlantic US coast, for example.
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Chapter 17 Pages 17-39 to 17-40
The State of the World’s Fisheries - A Bleak Picture
Maximum Sustainable Yield, Overfishing
and Ecosystem-Based Management
 Maximum sustainable yield isn’t an
easy number to establish.
 Scientists and fisheries managers
debate the number for different
species, often with widely differing
estimates.
 Pollution and other environmental
changes complicate the issue by
affecting the reproductive rates of
target species.
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The State of the World’s Fisheries - A Bleak Picture
Chapter 17 Pages 17-39 to 17-40
Maximum Sustainable Yield, Overfishing
and Ecosystem-Based Management
 Whatever the maximum sustainable yields are, however, the
evidence indicates overfishing in virtually all the world’s
fisheries.
 Fleets catch less than in previous years, yet have to range
farther.
 Indications are that half the marine fisheries are overfished
or already commercially extinct.
 The FAO estimates that 50% of the worldwide fish stocks are
fully exploited/overfished and 25% are depleted.
 The National Marine Fisheries Service estimates that half of
the fish stock in US waters is overfished.
 This estimate is based on species with known status—with
data lacking on most fish stocks, the picture could be much
worse.
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Chapter 17 Pages 17-40 to 17-42
The State of the World’s Fisheries - A Bleak Picture
The Problems with Overfishing
 Clearly, the evidence shows that the world’s fisheries
can’t sustain the present catch levels.
 Responding to declining species in the face of
continued or rising demand, however, the fishing
industry has become more efficient.
 By refining technology and methods, the
fishing fleets are taking ever larger proportions
of declining stocks.
 This response worsens the problem, as you might
expect. Already several fisheries show the longterm consequences of this response.
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Chapter 17 Pages 17-40 to 17-42
The State of the World’s Fisheries - A Bleak Picture
The Problems with Overfishing
 There are many problems with overfishing.
 In Canada, the Cod levels became so low that the
government closed the fishery in 1992.
 Putting 35,000 people out of work.
 In 1993, the National Marine Fisheries Service closed large
parts of the New England cod fishery.
 Another example is the North Atlantic swordfish. Between
1982 and 1990, the US catch declined 70%.
 The average fish weight fell from 52 kilograms (115 pounds)
to 27 kilograms (60 pounds).
 The Atlantic bluefin tuna declined by 80% in just three years
(1990 to 1993). This fish may be doomed to extinction.
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Chapter 17 Pages 17-40 to 17-42
The State of the World’s Fisheries - A Bleak Picture
The Problems with Overfishing
 Besides becoming more efficient, fisheries also respond by
turning to new, unexploited fisheries.
 These are fish that are usually lower in the trophic pyramid,
leading to a problem called fishing down the food chain.
 Creates problems with overfishing species such as the
herrings, sardines and anchovies.
 These species are prey fish – food for higher species.
 Fishing down the food chain also allows the
proliferation of other organisms low on the food web.
 For example, overfishing in the Black Sea removed fish
species that feed on plankton. This allowed rapid plankton
growth.
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 Another problem results when commercial fishing
disregards how fast species reproduce.
 Orange roughy example.
 Chilean seabass example.
 Another indirect problem is bycatch.
 Bycatch is the unintentional
capture of organisms.
Chapter 17 Pages 17-40 to 17-42
The State of the World’s Fisheries - A Bleak Picture
The Problems with Overfishing
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Chapter 17 Pages 17-42 to 17-43
The State of the World’s Fisheries - A Bleak Picture
Recommendations for Sustaining the
World’s Fisheries
 Given the state of the world’s fisheries, it is not surprising that
many environmental groups are disappointed with government
fishery management.
 The Pew Ocean Commission made four recommendations
to restore US fisheries as sustainable biological resources:
 Make the principal objective of US fisheries policies the
protection of marine ecosystems.
 Create an independent government agency responsible or
managing ocean resources.
 Invest in more marine research over the next five years. The
commission recommended doubling current funding.
 Establish a network of marine reserves
or protected areas.
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Chapter 17 Pages 17-44 to 17-48
Commercial Fishing
Commercial Fishing
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Chapter 17 Pages 17-44 to 17-46
Commercial Fishing
Commercial Fishing Methods
 Commercial fisheries primarily use five methods
for taking their catch.
 Gill nets.
 Drift net.
 Longline fishing.
 Purse seine nets.
 Trawling.
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Chapter 17 Pages 17-44 to 17-46
Commercial Fishing
Commercial Fishing
Drift Nets
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Chapter 17 Pages 17-44 to 17-46
Commercial Fishing
Commercial Fishing
Longlining
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Commercial Fishing
Chapter 17 Pages 17-44 to 17-46
Commercial Fishing
Purse Seining
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Chapter 17 Pages 17-44 to 17-46
Commercial Fishing
Commercial Fishing
Trawling
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Chapter 17 Pages 17-46 to 17-48
Commercial Fishing
The Economics of Commercial Fishing
 Compared to the industries involved with other
marine resources, the worldwide fishing industry
is unique in that, according to economic
estimates, the worldwide fish catch sells for less
than it costs to catch.
 Despite the apparent illogic, it’s not hard to
understand why governments do this.
 Loss of jobs.
 Although commercial fishing in its present state
appears unsustainable and very damaging to the
environment, it would be wrong to characterize
everyone in that trade as uncaring or unethical.
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Chapter 17 Pages 17-48 to 17-52
Who Owns the Sea?
Who Owns the Sea?
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Chapter 17 Pages 17-48 to 17-49
Who Owns the Sea?
The Origin of Territorial Waters
 The foundations of western legal views of the ocean
can be traced back to the 1490s.
 The Treaty of Tordesillas in 1493.
 Mare Liberum
 Defended the concept of a free ocean–access
to the high sea by every nation.
 By the early 18th century, Mare Liberum was
internationally recognized.
 The limit of territorial waters was 5 kilometers
(about three miles) from shore.
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Chapter 17 Pages 17-49 to 17-50
Who Owns the Sea?
The Truman Proclamation
 To protect US interests, President Harry Truman
issued the Truman Proclamation of 1945.
 It declared that “The U.S. regards the natural
resources of the subsoil and sea bed of the
continental shelf beneath the high seas but
contiguous to the coasts of the United States as
appertaining to the United States, subject to its
jurisdiction and control.”
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Chapter 17 Pages 17-50 to 17-52
Who Owns the Sea?
Exclusive Economic Zones
 In 1953, the Outer Continental Shelf Lands Act
solidified the Truman Proclamation.
 It granted control of the seabed and subsoil of the
outer continental shelf to the US federal
government.
 Was in response to a Declaration of Maritime
Zone signed by Chile, Ecuador, and Peru in 1952.
Extended jurisdiction to 350 kilometers from
coastline.
 Iceland followed.
 International controversy ensued.
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Chapter 17 Pages 17-50 to 17-52
Who Owns the Sea?
Exclusive Economic Zones
 UNCLOS - UN Convention on the Law of the Sea.
 UN conference in Geneva to settle issues.
 UNCLOS established the concept of the Exclusive
Economic Zone (EEZ).
 A nation’s EEZ extends 370 kilometers (about 200
nautical miles or 230 statute miles) from the
shoreline.
 Within the EEZ, a nation has complete control
of all resources, economic activity, and
environmental protection.
 Areas beyond the EEZs are the high seas or
international waters.
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Chapter 17 Pages 17-50 to 17-52
Who Owns the Sea?
Exclusive Economic Zones
 1983 Ronald Reagan established for the United
States an Exclusive Economic Zone within 200
nautical miles of its coasts.
 This doubled the size of the U.S.
 Omits shared resources in international waters.
 Other countries have EEZs of their own.
 May help to effectively maintain the ocean’s
resources.
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Chapter 17 Page 17-53
Biodiversity and the Future
Biodiversity and the Future
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Chapter 17 Page 17-53
Biodiversity and the Future
The Ultimate Resource
 Biodiversity raises the question of the importance
of a single species.
 It’s often hard to point to the importance of a single
organism.
 Biologist Paul Eherlich’s Airplane Analogy.
 The importance of biodiversity is that every organism
is a biological resource.
 In the end, the ultimate resource we get from the sea
is life itself.
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