Chapter 11

Sustaining Aquatic Biodiversity

Loss of biodiversity and cichlids

Nile perch: deliberately introduced in 1950s and 1960s to stimulate exports of the fish

Frequent algal blooms due toNutrient runoffSpills of untreated sewageLess algae-eating cichlids

Core Case Study: A Biological Roller Coaster Ride in Lake

Victoria

Natural Capital Degradation: The Nile Perch

Nile perch population is decreasing due to reduced food supply of smaller fishes (cichlids) and being overfished.

What Are the Major Threats to Aquatic Biodiversity?

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 Aquatic Biodiversity

Greatest marine biodiversity occurs inCoral reefsEstuaries Deep-sea ocean floor

Biodiversity is higherNear 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 oceansMarine – only 4% of the

world’s oceans are NOT affected by pollutionCoastal – 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 rubble

Freshwater HabitatsDamsExcessive water withdrawal

Invasive Species are Degrading Biodiversity

Invasive species - the “I” in HIPPCOThreaten native speciesDisrupt and degrade whole

ecosystemsThree Examples:

Water hyacinth: Lake Victoria (East Africa)

Asian swamp eel: waterways of south Florida

Purple loosestrife: indigenous to EuropeTreating with natural

predators—a weevil species and a leaf-eating beetle—Will it work?

Invasive Water Hyacinth

Science Focus: How Carp Have Muddied Some Waters

Lake Wingra, Wisconsin (U.S.): eutrophic, excessive nutrient inputs from run off with fertilizers from farms/lawnsContains invasive species

Purple loosestrife and the common carp, which devour the algae

Dr. Richard LathropRemoved carp from an area

of the lakeThis area appeared to

recover

Population Growth and Pollution Can Reduce Aquatic Biodiversity

The two “P’s” in HIPPCOBy 2020, 80% of the

world’s population will live near coasts

Population growth and pollution have drastic effects on ocean systems

Nitrates and phosphates mainly from fertilizers enter waterLeads to algal bloom and

eventual eutrophication, fish die offs

Toxic pollutants from industrial and urban areas kill some forms of aquatic life by poisoning them

Hawaiian Monk Seal

Plastic items from ships and litter on beaches kill seabirds, mammals, and sea 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 and 2100◦Destroy coral reefs◦Swamp some low-lying islands◦Drown many highly productive coastal

wetlands including New Orleans, Louisiana

Overfishing and Extinction

Overfishing – the “O” in HIPPCOMarine 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.

Fig. 11-6, p. 254

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Science Focus: Protecting and Restoring Mangroves

Protect and restore mangroves because they provide important ecological services.Reduce the impact of rising sea levelsProtect against tropical storms and

tsunamisCheaper 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 SeasTrawler fishing –

fish and shellfish 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 waters

How Can We Protect and Sustain Marine Biodiversity?

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 SpeciesWhy 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 waste.

Most of the ocean lies outside the legal jurisdiction of any country.

Treaties - CITES, Marine Mammal Protection Act, Endangered Species Act, Whale Conservation and Protection Act, International Convention on Biological Diversity.

Protecting Whales: 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

1970: U.S. Stopped all commercial whalingBanned all imports of whale products

1986: IWC imposed a moratorium on commercial whaling – this workedJapan ,Norway, Iceland, Russia do not

support the IWC ban.

Norwegian Whalers Harpooning a Sperm Whale

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.

Economic RewardsReconciliation 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 areas 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 Ecosystemsand Species

Offshore Fishing Zone – extends to 370 kilometers from its shores 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 and enforce.

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 SustainabilityPrimary 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 asCommercial fishingDredging reservesMining and waste disposalCore zone – No human activity allowedLess harmful activities allowed – recreational boating and

shippingFully protected marine reserves work and work fast

Fish populations doubleFish size grows by almost one-thirdReproduction triplesSpecies 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

TogetherIntegrated Coastal

Management 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 economic benefits

An atoll of Australia’s Great Barrier Reef

How Should We Manage and Sustain

Marine Fisheries?

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 markets.

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 Fish Harvests

Community Management of the Fisheries – allotment and enforcement systems. Norway’s Lofoten fishery (cod) is self-regulated with no participation by the Norwegian government.

Co-management of the Fisheries with the Government – sets quotas for various species and divide the quotas among communities.

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 OverfishingIndividual 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 - 1990Difficult to enforceU.S. - 1995 introduced tradable quotas to

regulate Alaska’s halibut fisheryProblems with the ITR approach

Transfers public ownership of fisheries in publically owned waters to private fishers

Squeezes out small fishing companiesFishing 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.IndividualsOrganizationsGovernments

Fig. 11-12, p. 265

SOLUTIONS

Managing FisheriesFishery Regulations BycatchSet catch limits well below the maximum sustainable yield

Use wide-meshed nets to allow escape of smaller fish

Improve monitoring and enforcement of regulations

Use net escape devices for seabirds and sea turtlesBan throwing edible and marketable fish back into the sea

Economic ApproachesSharply reduce or eliminate fishing subsidiesCharge fees for harvesting fish and shellfish from publicly owned offshore waters

AquacultureRestrict coastal locations for fish farms

Control pollution more strictly

Certify sustainable fisheries

Protect Areas

Establish no-fishing areas

Depend more on herbivorous fish species

Establish more marine protected areas

Nonnative Invasions

Rely more on integrated coastal management

Kill organisms in ship ballast water

Consumer InformationFilter organisms from ship ballast water

Label sustainably harvested fish Dump ballast water far at sea and replace with deep- sea water

Publicize overfished and threatened species

How Should We Protect and Sustain Wetlands?

To maintain the ecological and economic services of wetlands, we must maximize preservation of remaining wetlands and restoration of degraded and destroyed wetlands.

Coastal and Inland Wetlands are Disappearing around the World

U.S. has lost more than half of its coastal and inland wetlands since 1900.

Ecological Value:Highly productive wetlandsProvide natural flood and erosion controlMaintain high water quality; natural filtersEffected by rising sea levels due to global warming which will degrade aquatic biodiversity

We Can Preserve and Restore Wetlands

Laws for protection

Mitigation BankingAllows destruction of existing wetlands as long as an equal area of the same type of wetland is created or restored.

Ecologists argue this should be used only as a last resort.

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 Everglades?

“River of Grass”: South Florida, U.S.

Since 1948: damagesDrained DivertedPaved overNutrient pollution from agricultureInvasive plant species

1947: Everglades National Park unsuccessful protection project

Can We Restore the Florida Everglades?

1970s: political haggling for 20 years

1990: Comprehensive Everglades Restoration Plan (CERP)Restore the curving flow of most of the

Kissimmee RiverRemove canals and levees in strategic

locationsFlood 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 systems

Why isn’t this plan working? Cannot undue 120 years of ecological damage

done by agriculture and urban developmentWill 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 Major Threats

HIPPCO – major threats40% of the world’s rivers have been

dammed or otherwise engineered.Invasive species, pollution, climate change

Case Study: Can the Great Lakes Survive Repeated Invasions by

Alien Species?

Collectively, world’s largest body of freshwater.

Invaded by at least 162 nonnative species.Sea lampreyZebra mussel

Good and badQuagga musselAsian carp

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 CanadaDam System: 119 dams, 19 of which are

hydroelectric power plants.Pro–electricity; Con–salmon affected

Snake River: Washington State, U.S. Hydroelectric dams removedPro–salmon saved ; Con–economy affected

Natural Capital: Ecological Services of Rivers

We Can Protect Freshwater Ecosystems

by Protecting WatershedsFreshwater ecosystems protected through

LawsEconomic IncentivesRestoration Efforts

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 worldwide.

What Should Be Our Priorities for Sustaining Biodiversity and

Ecosystem Services?

2002: Edward O. WilsonComplete the mapping of the world’s

terrestrial and aquatic biodiversity.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.