Download - Preserving Aquatic Biodiversity
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 fishAdded nutrients – eutrophicationIntroduce water hyacinth – blocks light
Aquatic biodiversity
Greatest marine diversity in coral reefs and deep-sea floor
Higher near coasts than open oceanHigher in benthic layer than near the
surfaceHigher near tropics
How do humans benefit
FoodSeaweed (cosmetics)Chemicals
AntibioticsAnticancerHypertensionBone replacement
Destroying freshwater habitats
Draining wetlands – lost over 50 % of wetlands
Introduction of non-native speciesDams, diversions, canals, flood control
leveesRuin existing habitat or changing flow rate,
sediment deposits, spawning beds, migration patterns, plant life, nutrient cycles
Major loss of aquatic biodiversity by humans
OverfishingHabitat destruction
Coastal developmentRising sea levelTrawler boats
PollutionIntroduction 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 runoffAcid depositionPlant nutrients and oxygen demanding
wastesToxic chemicalsSedimentation from development
Protection of Marine Species
CITES1979 Global Treaty on Migratory SpeciesU.S. Marine Mammal Protection Act of
1972Endangered Species Act 1973Whale conservation and protection act
1976Changing 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 goodsJapan 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 ecosystemNow largest ecological restoration
project (at least $7.8 billion)
Columbia River Basin
Located in Pacific Northwest – 1,200 miles of river
Largest hydroelectric power systemProvides jobs, electricity, flood control,
stimulate industry/agricultureHurts 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 encounteringThermal pollution from power plantsCommercial fishingHuman 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 reasonsAgricultureHousing/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 erosionVote against wetland developmentEat less fish and seafood (more organic
veggies)