Chapter 12

Sustaining Aquatic Biodiversity

By the NumbersAbout 50% of the human population depends

on the seas for primary source of food.

About 90% of fish spawn in the world’s coral reefs, mangrove swamps, coastal wetlands or riversCoral reefs have the greatest biodiversity

About 1% of Earth’s surface is made of freshwater systems.

Major Causes of Species Loss in Marine Ecosystems (HIPPCO)

Habitat destructionPollutionErosionClimate changeInvasive species – caused over ½ of fish extinctions of

last centuary in the USOverfishing – lower size of fish populations; decreases

marine keystone species

All are made worse by the growth of the human population

A Biological Roller Coaster Ride in Lake Victoria

Loss of biodiversity and cichlids

Nile perch: deliberately introduced

Frequent algal bloomsNutrient runoffSpills of untreated

sewageLess algae-eating

cichlids

Reasons Why Protecting Aquatic Biodiversity is Difficult

1. Expanding human ecological footprint

2. Most of the ocean area lies outside political jurisdiction of any one country

3. Damage to oceans is not visible to most people

4. Many view the ocean as an inexhaustible resource

Human Activities Are Destroying Habitats

Habitat loss and degradation Marine – only 4% of

the world’s oceans are not affected by pollutionCoastalOcean floor: fishing

methodsFreshwater

DamsExcessive water

withdrawal

Invasive Species Are Degrading BiodiversityInvasive species

Threaten native speciesDisrupt and degrade

whole ecosystemsWater hyacinth: Lake

Victoria (East Africa)Asian swamp eel:

waterways of south Florida

Purple loosestrife: indigenous to Europe

Treating with natural predators—a weevil species and a leaf-eating beetle—

Invasive water hyacinth

Repeated Invasions by Alien Species in the Great Lakes

Collectively, world’s largest body of freshwater

Invaded by at least 162 nonnative speciesSea lampreyZebra mussel

Good and badQuagga musselAsian carp

Zebra Mussels Attached to a Water

Current Meter in Lake Michigan, U.S.

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

Removed carp from an area of the lakeThis area appeared to

recover

Population Growth and Pollution Can Reduce Aquatic Biodiversity

Nitrates and phosphates mainly from fertilizers enter waterLeads to algal

bloom and eventual eutrophication, fish die offs

Toxic pollutants from industrial and urban areas, plastic items Hawaiian Monk Seal

Climate Change Is a Growing Threat

Global warming: sea levels will rise and aquatic biodiversity is threatened ◦Coral reefs◦Swamp some low-lying islands◦Drown many highly productive coastal

wetlands New Orleans, Louisiana, and New York City

Overfishing and ExtinctionMarine and freshwater fish

Threatened with extinction by human activities more than any other group of species

Commercial extinction – industrialized fishing fleets can deplete marine life at a much faster rate. Can cause 80% in 10-15 years

Collapse of the cod fishery of the coast of Newfoundland and its domino effect leading to collapse of other species

By-catch – non-target species that are caught and killed duringy commercial fishing practices (seals, dolphins).

34% of marine, 71% of fresh water species face extinction within your life time.

Fig. 11-6, p. 254

900,000

800,000

700,000

600,000

500,000

400,000

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200,000

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01900 1920 1940 1960 1980 2000

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Major Commercial Fishing Practices

• Trawl fishing – involves dragging a weighted, funnel-shaped net along ocean floor in order to catch shellfish, flounder; most destructive of fishing practices.

• Purse seine – practice used to capture schooling fish (tuna); surrounds and encloses with a net.

• Drift net – uses hanging vertical nets in the water column with buoys to catch fish by gills.

• Longline fishing – involves putting out lines hung with thousands of baited hooks.

Industrial Fish Harvesting Methods are Vacuuming the Seas

• Trawl fishing – shrimp & scallops

• Purse seine – tuna & mackarel

• Longline fishing – tuna, swordfish & sharks

• Drift net – 1992 ban on using nets longer than 2.5 km

Aquaculture

• Deep sea aquaculture cage

– Form of “fish farming”

– These strains of fish are usually weaker than the “wild” form of the species. If weaker strains escape into the wild, could weaken wild population.

Protect and Sustain Marine Biodiversity

• We can help to sustain marine biodiversity by– Using laws and incentives to protect species– Setting aside marine reserves to protect

ecosystems– Using community-based coastal management

– Page 261

Legislation

1. Convention on International Trade in Endangered Species (CITES) 1973

2. Global Treaty on Migratory Species 19793. US Marine Mammal Protection Act 19724. US Endangered Species Act 19735. US Whale Conservation & Protection Act

19766. International Convention on Biological

Diversity 1995

International Whaling Commission

• Established by the International Convention for the Regulation of Whaling in 1946

• Allows Eskimos to continue hunting whales (cultural reasons)

• Japan, Norway and Iceland kill about 1300 whales per year for “scientific purposes”– Japan more than doubled whaling catch in

2005

Protecting Whales: Success Story… So FarCetaceans: Toothed whales

and baleen whales1946: International Whaling

Commission (IWC) – set annual quotas

1970: U.S. Stopped all commercial

whalingBanned all imports of whale

products1986: moratorium on

commercial whalingJapan ,Norway, Iceland, Russia

do not support the IWC ban

Economic Incentives Can Be Used to Sustain Aquatic Biodiversity

Tourism – example : sea turtles, worth more to local communities alive than dead (WWF)

Economic rewards

Marine Sanctuaries Protect Ecosystems and Species

Offshore fishing extends to 370 kilometers Exclusive economic zones-can take certain quotas

of fish High seas-beyond legal jurisdiction of any country

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

In 2006, President George W. Bush created the world’s largest marine reserve in Hawaii.

Ecosystem approach to sustainability

Core zoneNo human activity allowed

Less harmful activities allowedE.g., recreational boating and shipping

Fully protected marine reserves work fastFish populations doubleFish size growsReproduction triplesSpecies diversity increase by almost one-

fourth

Protecting Marine Biodiversity: Individuals and Communities Together

Integrated Coastal Management 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

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, careful consumer choices in seafood markets.

Estimating and Monitoring Fishery Populations is the First Step

Maximum Sustained Yield (MSY) – model to project the maximum number of fish that can be harvested from a fish stock without causing a population drop.

Optimum Sustained Yield (OSY) – takes into account interactions with other species and provides more room for error.

Tragedy in the commons activity

Some Communities Cooperate to Regulate Fish Harvests

Community management of the fisheries – allotment and enforcement systems. Norway’s Lofoten fishery (cod)

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 fishersCheck authenticity of ship flagsProsecution of offenders

Some Countries Use the Marketplace to Control

Overfishing

Individual transfer rights (ITRs) Control access to fisheries

New Zealand and IcelandDifficult to enforceUS 1995 to protect the halibut fishery

Problems with the ITR approachtransfer ownership of fisheries in

publically owned waters to private ownerssqueeze out small fishing companies

Consumer Choices Can Help to Sustain Fisheries and Aquatic Biodiversity

1997: Marine Stewardship Council (MSC), London – 20 nationsCertifies that fish caught using sustainable

practicesManage global fisheries more sustainably

IndividualsOrganizationsGovernments

How Should We Protect and Sustain Wetlands and Beach

Areas? To maintain the ecological and

economic services of wetlands, we must maximize preservation of remaining wetlands and restoration of degraded and destroyed

wetlands.

Best long-range strategy to reduce beach erosion:Prevent development on beach areas or allow

development only behind protective dunes

Coastal Wetlands

1. Serve as buffers against storms

2. Trap sediments and filter water

3. Act as nurseries for fish, shellfish and birds

4. More than half of the coastal wetlands have disappeared

Florida Everglades – Largest Ever Wetlands Restoration Project

“River of Grass”: south Florida, U.S.Since 1948: damaged

Drained DivertedPaved overNutrient pollution from agricultureInvasive plant species

1947: Everglades National Park unsuccessful protection project

Can We Restore the Florida Everglades?

1970s: political haggling1990: 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 US Army Corps of Engineers – federal agency

responsible for undoing development (dredging canals, levees)in Everglades. Ironically, this same agency oversaw the development of the Everglades since the 1940s.

Plan isn’t working……not sure why.

The World’s Largest Restoration Project

Managing River Basins Is Complex and Controversial

40% of the world’s rivers have been dammed or otherwise engineered

Columbia River: U.S. and CanadaDam system 119 dams , 19 of which are

hydroelectric power plantsPros –electricity ; con –salmon affected

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

Dams and Reservoirs1. May kill young salmon as they pass

through turbines

2. Slow downstream migration, exposing juvenile salmon to more predation

3. May prevent upstream migration of mature salmon

Columbia River Rehabilitation and Restoration

Ecosystem rehabilitation and salmon restoration on the Columbia River includes1. Building new hatcheries upstream of the

dams

2. Putting 40,000 miles of stream off limits to hydropower development

3. Reducing runoff of silt from logging roads.

Natural Capital: Ecological Services of Rivers

Protect Freshwater Ecosystems by Protecting Watersheds

Freshwater ecosystems protected throughLawsEconomic incentivesRestoration efforts

National Wild and Scenic Rivers Act-reestablish protection of rivers

Sustainable management of freshwater fishes

Priorities for Protecting Biodiversity, Ecosystem Services

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

terrestrial and aquatic biodiversityKeep old-growth forests intact; cease

their loggingIdentify and preserve hotspots and

deteriorating ecosystem services that threaten life

Ecological restoration projectsMake conservation financially rewarding