Sustaining Aquatic Biodiversity

G. Tyler Miller’sLiving in the Environment

13th Edition

Chapter 24

Key Concepts

Economic and ecological importance

Effects of human activities

Protecting and sustaining aquatic diversity

Protecting and sustaining fisheries

Protecting and restoring wetlands

Case Study: A Biological Roller Coaster Ride in Lake Victoria

• Lake Victoria has lost its endemic fish species to large introduced predatory fish.

A Biological Roller Coaster Ride in Lake Victoria

Reasons for Lake Victoria’s loss of biodiversity:• Introduction of Nile perch.• Loss of native cichlid species• Lake experienced algal blooms from

nutrient runoff.• Invasion of water hyacinth has blocked

sunlight and deprived oxygen.• Nile perch is in decline because it has

eaten its own food supply.

AQUATIC BIODIVERSITY• We know fairly little about the biodiversity of the world’s marine and freshwater systems.

• The world’s marine and freshwater systems provide important ecological and economic services.

The Importance of Aquatic Biodiversity

• The most biologically diverse habitats include:– Coral reefs– Estuaries– Deep ocean floor– Highest near the

coast– 25,000 known

fish species

The Importance of Aquatic Biodiversity:

Ecological and Economic • Food Items

– 6% of total protein; 16% of animal protein

• Many Chemicals– Cosmetics

• from seaweed– Medicines and Drugs

• Antibiotics and anticancer drug, adhesives, bone reconstructive materials

• seaweed, sponges, mollusks, coral barnacles, and other fish

APES Bell Ringer 11/28/2012

• What are 4 human impacts on aquatic biodiversity?

Human Impacts on Aquatic Biodiversity

• Species loss and endangerment• Marine habitat loss and

degradation• Freshwater habitat loss and

degradation• Overfishing• Nonnative species• Pollution and global warming

Species Loss and Endangerment

• Overfishing• Habitat destruction• Pollution• Freshwater species at greater risk

– Mussels, crayfish, amphibians, fish

Marine Habitat Loss and Degradation

• 53% of coastal wetlands in US have disappeared– Agriculture– Coastal development

• 58% of world’s coral reefs are threatened– Coastal development– Pollution– Warmer ocean temperatures

• Two-thirds of US estuaries are at risk from pollution

• 35% of world’s mangroves have disappeared

Freshwater Habitat Loss and Degradation

• The world has lost more than half of its inland wetlands– Agricultural and urban development

• 60% of the world’s larger rivers are fragmented by dams, diversions, and canals

• Flood control levees and dikes– Alter and destroy aquatic habitats– Disconnect rivers from their floodplains– Eliminate wetlands and backwaters

(spawning areas)

Overfishing

• 75% of the world’s 200 commercially valuable marine fish species are overfished

• Overfishing leads to commercial extinction

• Depletions and extinction of species unintentionally caught as bycatch

Non-native Species

• Deliberate or accidental introduction into coastal waters, lakes and wetlands– purple loosestrife– Asian swamp eel– zebra mussle

• Displace or cause extinction of native species– 68% of fish extinctions

Pollution and Global Warming

• Major pollution threats– Oil– Acid deposition– Plant nutrients– Toxic chemicals– Coastal

development– Sediment and soil

erosion

• Global warming could– alter migration and

feeding patterns– increase ocean

temperature– raise sea levels

• 44% comes from runoff from developed coastal areas

PROTECTING AND SUSTAINING MARINE BIODIVERSITY

• Six of the world’s seven major turtle species are threatened or endangered because o human activities.

Figure 12-4

Protect endangered and threatened species

• Example: Sea turtle– Turtle extrusion devices (TEDs)

LoggerheadOlive ridley

Leatherback

Hawksbill

Green turtleKemp's Ridley

Black turtle

Australian flatback

Shrimp trawler

Area enlarged right

Turtle Extrusion Device

Case Study: The Florida Manatee and Water Hyacinths

• Manatee can eat unwanted Water Hyacinths.

• Endangered due to:– Habitat loss.– Entanglement from

fishing lines and nets.– Hit by speed boats.– Stress from cold.– Low reproductive rate

Case Study: Commercial Whaling

• After many of the world’s whale species were over-harvested, commercial whaling was banned in 1960, but the ban may be overturned.

Commercial Whaling

• Despite ban, Japan, Norway, and Iceland kill about 1,300 whales of certain species for “scientific purposes”.– Although meat is still

sold commercially.

Key Concepts

Economic and ecological importance

Effects of human activities

Protecting and sustaining aquatic diversity

Protecting and sustaining fisheries

Protecting and restoring wetlands

Protecting and Sustaining Marine Biodiversity

• Identifying and protecting endangered and threatened species– Sea turtles

• Turtle extrusion devices (TEDs)• National and International laws and

treaties• CITES - Convention on International Trade

and Endangered Species• Global Treaty on Migratory Species• US Marine Mammal Protection Act• US Endangered Species Act• US Whale Conservation and Protection Act• International Convention on Biological

Diversity

Protecting and Sustaining Marine Biodiversity

• Establish marine protected areas– Coastal nations have sovereignty over

waters and seabeds up to 12 miles offshore

– Jurisdiction over their Exclusive Economic Zone extends 200 miles offshore

• Integrated coastal management– community based attempt to develop

and use coastal resources sustainably

Protecting and Sustaining Marine Biodiversity

• Regulating and preventing ocean pollution

• Sustaining management of marine fisheries

Managing and Sustaining the World’s Marine Fisheries

• Fishery regulation– Set, monitor, and enforce fishery catch limits below estimated MSY (maximum sustained yield)– Divide up fishing quotas– Require selective gear– Improve monitoring and enforcement

• Economic approached– Reduce or eliminate subsidies– Impose fees for harvesting fish and shellfish from public managed offshore waters– Certify sustainable fisheries

Managing and Sustaining the World’s Marine Fisheries

• Bycatch reduction– Wider mesh fish nets– Extrusion devices– Observers on boats– Multiple species licensing– Laws prohibiting throwing edible and marketable fish back to sea

Managing and Sustaining the World’s Marine Fisheries

• Protected areas– Establish no-fishing marine areas– Protect marine habitats that are in good condition and disregard potentially hopeless cases– Strengthen commitment to marine biodiversity protection

• Non-native invasions– Kill organisms in ship ballast water– Develop filters and traps– Require ships to dump ballast water beyond 200 mile limit

Managing and Sustaining the World’s Marine Fisheries

• Consumer information– Use labeling to identify fish that have been harvested sustainably

• Aquaculture– Restrict location of fish farms to reduce loss of mangrove forests– Enact and enforce stricter pollution regulations– Increase productions of herbivorous aquaculture fish species

Protecting, Sustaining, and Restoring Wetlands

• Regulations– federal permit required

• Mitigation banking– allows destruction of existing wetlands if an equal area

of they same type of wetland is created or restored• Land use planning

– steer agriculture and mining away from wetlands• Wetland restoration

– often has limited success• Control of invasive species

– purple loosestrife

Restoring the Florida Everglades

• Natural flow of the Everglades has been diverted or disrupted.

• Farmers planted vast agricultural land to sugarcane and vegetables.

• Established Everglades National Park. Became the most endangered park.

• Massive plumbing and land development projects cut off water flow

Restoring the Florida Everglades

• 1990 began the world’s largest ecological restoration project.– restore he curving flow of

more than half of the Kissimmee River.

– remove 400 km of canals and levees

– create artificial marshes in previous farmland

– add land adjacent to Everglades National Park

– create network of artificial marshes

– create 18 large reservoirs– capture much of the water

flowing out to sea and return it to the Everglades

Protecting, Sustaining, and Restoring Wetlands

Protecting, Sustaining, and Restoring Lakes Pollution

Invasive species

Water levels

Cultural eutrophication

Zebra mussel

Protecting, Sustaining, and Restoring Rivers

Pollution Disruption of

water flow Loss of

biodiversity Invasive

species

Protecting, Sustaining, and Restoring Rivers Disruption of water flow

119 dams, 19 hydroelectric dams Salmon population

dropped 94%

Salmon Restoration Project upstream hatcheries fish ladders transport juveniles

around dams turning off turbines

PROTECTING, SUSTAINING, AND RESTORING LAKES AND RIVERS• We can help sustain freshwater fisheries

by building and protecting populations of desirable species, preventing over-fishing, and decreasing populations of less desirable species.

• A federal law helps protect a tiny fraction of U.S. wild and scenic rivers from dams and other forms of development.– National Wild and Scenic Rivers Act

(1968).