Sustaining Aquatic Biodiversity
Core Case Study: A Biological Roller Coaster
Ride in Lake Victoria
Loss of biodiversity and cichlids
Nile perch: deliberately
introduced in 1950s and 1960s
to stimulate exports of the fish
Frequent algal blooms due to
Spills of untreated sewage
Less algae-eating cichlids
Natural Capital Degradation:
The Nile Perch
decreasing due to
supply of smaller
What Are the Major Threats to Aquatic
Aquatic species are threatened by habitat loss,
invasive species, pollution, climate change, and
overexploitation, all made worse by the growth of
the human population. (HIPPCO)
We Have Much to Learn about
Greatest marine biodiversity occurs in
Deep-sea ocean floor
Biodiversity is higher
Near the coasts because of great variety of producers,
habitats, and nursery areas than in the open sea
In the bottom region than in the surface region of the
ocean due to a greater variety of habitats
Human Activities are Destroying and
Degrading Aquatic Habitats
Habitat loss and degradation – the “H”
in HIPPCO – the greatest threat to
the biodiversity of oceans
Marine – only 4% of the world’s
oceans are NOT affected by
Coastal – coral reefs, mangrove
forests, and coastal wetlands
Ocean floor – effect of trawlers
which drag huge nets weighted
with heavy chains and steel
plates, reduce coral reefs to
Excessive water withdrawal
Invasive Species are Degrading Biodiversity
Invasive species - the “I” in HIPPCO
Threaten native species
Disrupt and degrade whole
Water hyacinth: Lake Victoria (East
Asian swamp eel: waterways of
Purple loosestrife: indigenous to
Europe Invasive Water Hyacinth
Treating with natural predators—a
weevil species and a leaf-eating
beetle—Will it work?
Science Focus: How Carp Have Muddied
Lake Wingra, Wisconsin (U.S.):
eutrophic, excessive nutrient inputs
from run off with fertilizers from
Contains invasive species
Purple loosestrife and the common
carp, which devour the algae
Dr. Richard Lathrop
Removed carp from an area of the
This area appeared to recover
Population Growth and Pollution Can Reduce
The two “P’s” in HIPPCO
By 2020, 80% of the world’s
population will live near coasts
Population growth and pollution
have drastic effects on ocean
Nitrates and phosphates mainly
from fertilizers enter water
Leads to algal bloom and
eventual eutrophication, fish Hawaiian Monk Seal
Toxic pollutants from industrial Plastic items from ships and litter on
and urban areas kill some forms beaches kill seabirds, mammals, and sea
of aquatic life by poisoning them turtles – POLLUTION
Climate Change Is a Growing Threat
The “C” in HIPPCO
Global Warming: sea levels will rise and aquatic biodiversity is
threatened – during the past 100 years, average sea levels have
risen an average of 10-20 cm and scientists estimate they will rise
another 18-59 cm, and perhaps as high as 1-1.6 m between 2050
◦ Destroy coral reefs
◦ Swamp some low-lying islands
◦ Drown many highly productive coastal wetlands including New
Overfishing and Extinction
Overfishing – the “O” in HIPPCO
Marine and Freshwater Fish
Threatened with extinction by human activities more than any other
group of species.
Commercial Extinction – due to overfishing which occurs when it is
no longer profitable to continue fishing the affected species.
Industrialized fishing fleets can deplete marine life at a much faster rate.
Can deplete 80% of target fish species in 10-15 years.
Collapse of the cod fishery off the coast of Newfoundland and its domino
effect leading to collapse of other species.
Bycatch – seals, dolphins (non-target species, 1/3 of annual fish catch)
Biological Extinction – 34% of marine and 71% of fresh water species
face extinction within your life time.
Fish landings (tons)
1900 1920 1940 1960 1980 2000
Year Fig. 11-6, p. 254
Science Focus: Protecting and Restoring
Protect and restore mangroves because they provide
important ecological services.
Reduce the impact of rising sea levels
Protect against tropical storms and tsunamis
Cheaper than building concrete sea walls
Due to coastal development in Indonesia, about 70% of
mangroves have been degraded or destroyed. Now
efforts to protect those areas.
Case Study: Industrial Fish Harvesting
Methods are Vacuuming the Seas
Trawler fishing – fish
Purse-seine fishing –
surface dwelling species
like tuna, mackerel
Long-lining – open
ocean fish species like
tuna, swordfish, sharks
Drift-net fishing –
1992 ban on the use of
drift nets longer than
2.5 km in international
How Can We Protect and Sustain Marine
We can help to sustain marine biodiversity by using laws
and economic incentives to protect species, setting aside
marine reserves to protect ecosystems, and using
community-based integrated coastal management.
Legal Protection of Some Endangered and
Threatened Marine Species
Why is it hard to protect marine biodiversity?
Human ecological footprint and fishprint are expanding.
Much of the damage in the ocean is not visible.
The oceans are incorrectly viewed as an inexhaustible
resource that can absorb an almost infinite amount of
Most of the ocean lies outside the legal jurisdiction of
Treaties - CITES, Marine Mammal Protection Act,
Endangered Species Act, Whale Conservation and
Protection Act, International Convention on Biological
A Success Story… So Far
Cetaceans: two groups – toothed whales
and baleen whales
Overharvesting has driven some valuable
species to almost extinction.
1946: International Whaling
Commission (IWC) – set annual quotas
Stopped all commercial whaling
Banned all imports of whale products
1986: IWC imposed a moratorium on
commercial whaling – this worked
Japan ,Norway, Iceland, Russia do not
support the IWC ban.
Norwegian Whalers Harpooning a
Economic Incentives Can Be Used to
Sustain Aquatic Biodiversity
Tourism – example: sea turtles, worth more to local
communities alive than dead (WWF); brings in almost
three times more money than does the sale of turtle
products such as meat, leather, and eggs.
Reconciliation Ecology – science of inventing, establishing, and
maintaining habitats to conserve species diversity in places
where people live, work, and play. Example: artificial coral
reef created in Israel.
Case Study: Holding Out Hope for Marine
Turtles (6 of the 7 species are endangered)
Carl Safina, Voyage of the Turtle
◦ Studies of the leatherback turtle
Threats to the leatherbacks
◦ Trawlers destroy coral reefs which is their feeding grounds
◦ Entangled in fishing nets and lines
◦ Pollution—discarded plastic bags
◦ Climate change—rising sea levels will flood nesting and feeding
Communities protecting the turtles
Turtle Excluder Devices required on trawlers (shrimp boats) by
the U.S. government
An Endangered Leatherback Turtle is
Entangled in a Fishing Net
Marine Sanctuaries Protect Ecosystems
Offshore Fishing Zone – extends to 370 kilometers from its
Exclusive Economic Zones – foreign fishing vessels can take certain
quotas of fish within these zones with a government’s permission.
High Seas – ocean area’s beyond the legal jurisdiction of any country.
Laws and treaties pertaining to the high seas are difficult to monitor
Law of the Sea Treaty – world’s coastal nations have jurisdiction
over 36% of the ocean surface and 90% of the world’s fish stocks.
Marine Protected Areas (MPAs) – 4000 world wide, 200 in US
waters. Most MPAs allow ecologically harmful activities like
trawling, dredging, and resource extraction.
Establishing a Global Network of Marine Reserves:
An Ecosystem Approach to Sustainability
Primary Objective – protect and sustain whole marine ecosystems for current and
future generations instead of focusing primarily on protecting individual species.
Marine Reserves closed to extractive activities such as
Mining and waste disposal
Core zone – No human activity allowed
Less harmful activities allowed – recreational boating and shipping
Fully protected marine reserves work and work fast
Fish populations double
Fish size grows by almost one-third
Species diversity increase by almost one-fourth
But, less than 1% of the world’s ocean area is closed to fishing in marine reserves.
Protecting Marine Biodiversity:
Individuals and Communities Together
Community-based effort to
develop and use coastal
resources more sustainably
Community-based group to
prevent further degradation
of the ocean
More that 100 such groups
Seek reasonable short term
trade offs that can lead to
long term ecological and
An atoll of Australia’s Great Barrier Reef
How Should We Manage and Sustain
Sustaining marine fisheries will require improved
monitoring of fish populations, cooperative fisheries
management among communities and nations, reduction of
fishing subsidies, and careful consumer choices in seafood
Estimating and Monitoring Fishery Populations
Is the First Step
Maximum Sustained Yield (MSY)—mathematical model where
the maximum number of fish that can be harvested annually without
causing a population drop is calculated. Traditional approach.
Optimum Sustained Yield (OSY)—takes into account
interactions with other species and allows more room for error.
Multispecies Management—of a number of interaction species,
which accounts for competition and predator-prey interactions.
Large Marine Systems—using large complex computer models.
Precautionary Principle—use this method because of the
uncertainty of all the above methods.
Some Communities Cooperate to Regulate
Community Management of the Fisheries – allotment and
enforcement systems. Norway’s Lofoten fishery (cod) is
self-regulated with no participation by the Norwegian
Co-management of the Fisheries with the Government –
sets quotas for various species and divide the quotas among
Government Subsidies Can Encourage
Overfishing: $30-34 Billion Around the World
2007: World Trade Organization, U.S.
Proposed a ban on fishing subsidies.
Reduce illegal fishing on the high seas and in coastal waters.
Close ports and markets to such fishers.
Check authenticity of ship flags.
Prosecution of offenders.
Some Countries Use the Marketplace
to Control Overfishing
Individual Transfer Rights (ITRs) – assigned to each
fisherman – can be bought, sold, or leased like private property.
Use to control access to fisheries
New Zealand – 1986 and Iceland - 1990
Difficult to enforce
U.S. - 1995 introduced tradable quotas to regulate Alaska’s
Problems with the ITR approach
Transfers public ownership of fisheries in publically owned
waters to private fishers
Squeezes out small fishing companies
Fishing quotas are often set too high
Consumer Choices Can Help to Sustain
Fisheries and Aquatic Biodiversity
1997: Marine Stewardship Council (MSC), London –
operates in more than 20 nations
Support sustainable fishing and certifies that fish are
caught using sustainable practices.
Manage global fisheries more sustainably.
Fishery Regulations Bycatch
Set catch limits well below the Use wide-meshed nets to
maximum sustainable yield allow escape of smaller fish
Improve monitoring and Use net escape devices for
enforcement of regulations seabirds and sea turtles
Economic Approaches Ban throwing edible and
Sharply reduce or eliminate marketable fish back into the
fishing subsidies sea
Charge fees for harvesting fish Aquaculture
and shellfish from publicly Restrict coastal locations for
owned offshore waters fish farms
Protect Areas Control pollution more strictly
Depend more on herbivorous
Certify sustainable fisheries
Establish no-fishing areas
Establish more marine protected Nonnative Invasions
areas Kill organisms in ship ballast
Rely more on integrated coastal water
management Filter organisms from ship
Consumer Information ballast water
Label sustainably harvested fish Dump ballast water far at sea
Publicize overfished and and replace with deep- sea
threatened species water
Fig. 11-12, p. 265
How Should We Protect and Sustain
To maintain the ecological and economic services of
wetlands, we must maximize preservation of
remaining wetlands and restoration of degraded and
Coastal and Inland Wetlands are
Disappearing around the World
U.S. has lost more than half of its coastal and inland
wetlands since 1900.
Highly productive wetlands
Provide natural flood and erosion control
Maintain high water quality; natural filters
Effected by rising sea levels due to global warming
which will degrade aquatic biodiversity
We Can Preserve and Restore Wetlands
Laws for protection
Allows destruction of existing wetlands as long as
an equal area of the same type of wetland is created
Ecologists argue this should be used only as a
Individuals Matter: Restoring a Wetland
Jim Callender: 1982
Scientific knowledge + hard work =
a restored wetland in California, U.S.
Marsh used again by migratory fowl
Natural Capital Restoration:
Wetland Restoration in Canada
Case Study: Can We Restore the Florida
“River of Grass”: South Florida, U.S.
Since 1948: damages
Nutrient pollution from agriculture
Invasive plant species
1947: Everglades National Park unsuccessful protection
Can We Restore the Florida Everglades?
1970s: political haggling for 20 years
1990: Comprehensive Everglades Restoration Plan
Restore the curving flow of most of the Kissimmee
Remove canals and levees in strategic locations
Flood 240 sq. km farmland to create artificial marshes
Can We Restore the Florida Everglades?
Comprehensive Everglades Restoration Plan (CERP) cont…
Create reservoirs and underground water storage areas
Build new canals, reservoirs and efficient pumping
Why isn’t this plan working?
Cannot undue 120 years of ecological damage done by
agriculture and urban development
Will take at least 50 years and too expensive
The World’s Largest Restoration Project
How Can We Protect and Sustain
Freshwater Lakes, Rivers, and Fisheries?
Freshwater ecosystems are strongly affected by human
activities on adjacent lands, and protecting these ecosystems
must include protection of their watersheds.
Freshwater Ecosystems are Under
HIPPCO – major threats
40% of the world’s rivers have been dammed or otherwise
Invasive species, pollution, climate change
Case Study: Can the Great Lakes Survive
Repeated Invasions by Alien Species?
Collectively, world’s largest body
Invaded by at least 162 nonnative
Good and bad
Zebra Mussels Attached to a Water Current
Meter in Lake Michigan, U.S.
Managing River Basins is
Complex and Controversial
Columbia River: U.S. and Canada
Dam System: 119 dams, 19 of which are hydroelectric power
Pro–electricity; Con–salmon affected
Snake River: Washington State, U.S.
Hydroelectric dams removed
Pro–salmon saved ; Con–economy affected
Natural Capital: Ecological Services of Rivers
We Can Protect Freshwater Ecosystems
by Protecting Watersheds
Freshwater ecosystems protected through
National Wild and Scenic Rivers Act—passed in 1968 to protect
rivers and river segments with outstanding scenic, recreational,
geological, wildlife, historical, or cultural values.
Sustainable management of freshwater fishes involves encouraging
populations of commercial/sport species, prevents overfishing, and
reduces or eliminates less desirable fish populations.
What Should Be Our Priorities for Sustaining
Biodiversity and Ecosystem Services?
Sustaining the world’s biodiversity and ecosystem
services will require mapping terrestrial and
aquatic biodiversity, maximizing protection of
undeveloped terrestrial and aquatic areas, and
carrying out ecological restoration projects
What Should Be Our Priorities for Sustaining
Biodiversity and Ecosystem Services?
2002: Edward O. Wilson
Complete the mapping of the world’s terrestrial and
Keep old-growth forests intact; cease their logging.
Identify and preserve hotspots and deteriorating
ecosystem services that threaten life.
Ecological restoration projects.
Make conservation financially rewarding.