Preserving Aquatic Biodiversity Chapter 12

Lake Victoria The second largest freshwater lake in the world How have humans changed it? Introduced Nile perch – killed other fish Added nutrients – eutrophication Introduce water hyacinth – blocks light

Aquatic biodiversity Greatest marine diversity in coral reefs and deep-sea floor Higher near coasts than open ocean Higher in benthic layer than near the surface Higher near tropics

How do humans benefit Food Seaweed (cosmetics) Chemicals Antibiotics Anticancer Hypertension Bone replacement

Destroying freshwater habitats Draining wetlands – lost over 50 % of wetlands Introduction of non-native species Dams, diversions, canals, flood control levees Ruin existing habitat or changing flow rate, sediment deposits, spawning beds, migration patterns, plant life, nutrient cycles

Major loss of aquatic biodiversity by humans Overfishing Habitat destruction Coastal development Rising sea level Trawler boats Pollution Introduction of alien species

Nonnative examples Asian swamp eel – Florida, eats everything, can breath air, cross to new waterways Purple loosestrife – wetlands, perennial plant in Eurasia, spreads rapidly, no native predators, displaces native plants, reduces biodiversity Zebra mussels – Great Lakes, from ship ballasts, no natural predators, displaced other mussels, interrupted food chain, clogged pipes, grows in large masses on everything

Major pollution threats Oil – especially from runoff Acid deposition Plant nutrients and oxygen demanding wastes Toxic chemicals Sedimentation from development

Protection of Marine Species CITES 1979 Global Treaty on Migratory Species U.S. Marine Mammal Protection Act of 1972 Endangered Species Act 1973 Whale conservation and protection act 1976 Changing fishing nets and fishing practice

Whaling International Convention for the Regulation of Whaling formed the IWC to set quotas (often ignored) IWC set moratorium on commercial whaling since 1986 (Inuits still allowed to hunt whale) many populations recovered US banned whaling and importing goods Japan and Norway still are large whaling countries

Restoring Wetlands US requires a federal permit to drain/alter a wetland over 3 acres Mitigation banking – allows development of wetlands if an equal area elsewhere is created or restored Use proper planning to keep development/Ag away Prevent introduction of alien species

Florida’s Mistake Army Corps of Engineers diverted much of the Everglade’s natural flow with levees and canals Wetlands dried and were converted to farmland Runoff from fields introduced excess nutrients Disrupted entire ecosystem Now largest ecological restoration project (at least $7.8 billion)

Columbia River Basin Located in Pacific Northwest – 1,200 miles of river Largest hydroelectric power system Provides jobs, electricity, flood control, stimulate industry/agriculture Hurts habitats especially migratory fish (salmon) Northwest Power Act 1980 – find way to generate power and rebuild wild salmon and other fish populations

Protecting Rivers National Wild and Scenic Rivers Act 1968 – waterways kept free from development, no motors, no alterations A river can be designated by congress based on outstanding scenic, recreational, geological, wildlife, historical, or cultural value

The Great Lakes Faces several threats Alien species, like the zebra mussel, is the greatest, but also is encountering Thermal pollution from power plants Commercial fishing Human sewage (mostly processed) Acid rain (but there is more to the east)

Act Now Approximately 50% of the world’s original coastal wetlands have been lost Main reasons Agriculture Housing/building development

Commercial fishing techniques While many systems are bad for the environment, these appear to be the worst Trawling - nets destroy ocean floor habitat Drift nets (more than 2 miles long) - kill many mammals, turtles and birds Longlining - creates a lot of bycatch such as dolphin, shark, pilot whales, birds, and turtles

What can you do? Use comsumer power to buy products that do not threaten aquatic species Use environmentally friendly cleaners in the home Prevent soil erosion Vote against wetland development Eat less fish and seafood (more organic veggies)