Transcript ECE Chapter 11 Slides

We Have Much to Learn about
Aquatic Biodiversity
• Greatest marine biodiversity
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Coral reefs
Estuaries
Coastlines
Deep-ocean floor
Natural Capital
Marine Ecosystems
Ecological Services
Economic Services
Climate moderation
Food
CO 2 absorption
Harbors and
transportation routes
Nutrient cycling
Waste treatment
Reduced storm impact
(mangroves, barrier
islands, coastal
wetlands)
Coastal habitats for
humans
Recreation
Employment
Oil and natural gas
Habitats and nursery
areas
Minerals
Fig. 8-5, p. 172
Natural Capital
Freshwater Systems
Ecological Services
Economic Services
Climate moderation
Food
Nutrient cycling
Drinking water
Waste treatment
Irrigation water
Flood control
Groundwater
recharge
Hydroelectricity
Transportation
corridors
Recreation
Habitats for many
species
Employment
Fig. 8-15, p. 181
Human Activities Are Destroying and
Degrading Aquatic Habitats
• Marine
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Acidifying Oceans impacting coral reefs
Harvesting mangrove forests
Harvesting seagrass beds
Sea-level rise
Ocean floor: trawling and dredging
• Freshwater
• Dams
• Excessive water withdrawal for irrigation and human
use
Natural Capital Degradation: Area of Ocean
Bottom Before and After a Trawler
Fig. 11-2, p. 252
Invasive Species Are Degrading
Aquatic Biodiversity
• Invasive species
• Threaten native species
• Degrade ecosystem
• Three examples
• Northern Snakehead in Rivers and Streams
• Lionfish in the Atlantic
• Carp in Great Lakes
Invasive Northern Snakehead
Native to Asia
Released from fish
markets or fish farms
Able to enter new
waterways over land
Fig. 11-3, p. 254
Invasive Lionfish
Native to Pacific
Can lay up to 30,000 eggs every
few days
Fig. 11-3, p. 254
Numerous Invasive Carp Species
• Accidentally introduced
• Significantly alter food webs
• “Muddy” waters and restrict plant growth
Various Pollutants
• Noise
• Nitrates and phosphates, mainly from fertilizers,
• Leads to eutrophication
Various Pollutants
• Toxic pollutants from industrial and urban areas
• PCBs, heavy metals
• Plastics
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
• New York City area
Overfishing and Extinction
• Fishery: Particular wild aquatic species suitable for
commercial harvesting in a specific area
• Marine and freshwater fish hreatened with extinction by human
activities more than any other group of species
Overfishing and Extinction
• Commercial extinction: no longer economically
feasible to harvest a species
• Collapse of a fishery often seems sudden (tipping
point)
• Fewer larger fish
Natural Capital Degradation: Collapse of the
Cod Fishery Off the Canadian Coast
Fig. 11-7, p. 257
Case Study: Industrial Fish Harvesting
Methods
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Trawler fishing
Purse-seine fishing
Drift-net fishing
Longlining
• Aquaculture or fish farming
• Bycatch problem (unwanted species killed)
Fish farming in
cage
Trawler fishing
Spotter airplane
Sonar
Purse-seine
fishing
Drift-net fishing
Long line fishing
Float
Buoy
lines with
hooks
Deep sea
aquaculture cage
Fish caught by gills
Fig. 11-8, p. 259
An Endangered Leatherback Turtle is
Entangled in a Fishing Net
Fig. 11-10, p. 262
Legal Protection of Some Endangered and
Threatened Marine Species
• Why is it hard to protect marine biodiversity?
1.
Much of the damage in the ocean is not visible
2.
The oceans are incorrectly viewed as an inexhaustible
resource
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Most of the ocean lies outside the legal jurisdiction of any
country (the high seas)…”tragedy of the commons”
Economic Incentives To Sustain
Biodiversity
• Tourism
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Birding
Sea turtles
Whales
Coral Reefs
• Economic values:
• Est. $300million to $1 billion FL economy from
snorkeling/scuba tourism
• Est. $7 billion to US economy from recreational fishing
and wildlife tourism
Marine Sanctuaries Protect
Ecosystems and Species
• Offshore fishing
• Exclusive economic zones for countries to use as a
national resource (food, energy…)
• 200 nautical miles
• High seas governed by treaties that are hard to
enforce
Marine Sanctuaries Protect
Ecosystems and Species
• Marine Protected Areas (MPAs) – protected areas of
ocean, estuaries, coastline, etc…that limit human
activity (aka Marine Reserves)
• Goals
• Limit fishing
• Protect ecosystems and biodiversity
• Regenerate marine populations and food webs
• ~1% of US waters are “no take” MPAs
Marine Sanctuaries Protect
Ecosystems and Species
• Marine reserves closed to all or most human activity
• Commercial fishing
• Dredging
• Mining and waste disposal
• Goals
• Create areas not impacted by (over)fishing
• Act as spawning grounds
• Regenerate marine populations and food webs
• ~1% of international waters are reserves
• Marine scientists want 30-50%
Estimating and Monitoring Fishery
Populations
• Challenges in estimating fish populations
• Lack of Data on individual species
• Locations
• Population Dynamics (Birth/Death rates)
• Lack of Data on interspecies relationships
• Lack of communication and oversight between
countries
Estimating and Monitoring Fishery
Populations
• Optimum sustained yield (OSY) – calculation that
estimates the number of fish that can be sustainably
harvested
• Goal to maintain and sustain ecosystem (not just
that one fish)
Some Communities Cooperate to
Regulate Fish Harvests
• Co-management of the fisheries with the
government
• Government sets quotas for species and divides/sells
the quotas among fishing communities
• Limits fishing seasons
• Regulates fishing gear
• US regulation by NOAA (National Oceanic and
Atmospheric Administration)
Some Communities Cooperate to
Regulate Fish Harvests
• International Challenges:
• Countries each have their own system and goals
• Ex. Whale hunting
• High Seas difficult
to manage (no
international laws)
Government Subsidies Can Encourage
Overfishing
• Governments spend 30-34 billion dollars per year
subsidizing fishing
• Often leads to overfishing by supporting:
• Larger boats
• Greater ranges of fishing fleets
• Discourages long-term sustainability of fish
populations
Consumer Choices Can Help to Sustain Fisheries
and Aquatic Biodiversity
• Try to buy from a sustainable fishery
• Marine Stewardship Council (MSC)
• Certifies sustainably produced seafood
• http://www.msc.org/
• http://www.seafoodwatch.org/
• Proper use of sustainable aquaculture
• Plant eating fish best – ex. Tilapia
Solutions
Managing Fisheries
Fishery Regulations
Bycatch
Set low catch limits
Improve monitoring and enforcement
Use nets that allow escape
of smaller fish
Use net escape devices for
seabirds and sea turtles
Economic Approaches
Reduce or eliminate fishing subsidies
Certify sustainable fisheries
Protect Areas
Establish no-fishing areas
Establish more marine protected
areas
Consumer Information
Label sustainably harvested fish
Publicize overfished and threatened
species
Aquaculture
Restrict coastal locations of
fish farms Improve pollution
control
Nonnative Invasions
Kill or filter organisms from
ship ballast water
Dump ballast water at sea
and replace with deep-sea
water
Coastal and Inland Wetlands
• Highly productive ecosystems
• Provide natural flood and erosion control
• Maintain high water quality; natural filters
We Can Preserve and Restore
Wetlands
• Laws for protection
• Zoning laws steer development away from wetlands
• In U.S., need permit to fill wetlands greater than 3
acres
• Mitigation banking
• Can destroy wetland if create one of equal area
• Ecologists argue this as a last resort
Case Study: Can We Restore the
Florida Everglades? (1)
• “River of Grass”: south Florida, U.S.
• Damage in the 20th century
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Drained
Diverted
Paved over
Nutrient pollution from agriculture
Invasive plant species
• 1947: Everglades National Park unsuccessful
protection project
Case Study: Can We Restore the
Florida Everglades? (2)
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Restore curving flow of ½ of Kissimmee River
Remove canals and levees in strategic locations
Flood farmland to create artificial marshes
Create 18 reservoirs to create water supply for
lower Everglades and humans
5. Recapture Everglades water flowing to sea and
return it to Everglades
The World’s Largest Restoration
Project
Fig. 11-13, p. 269
The World’s Largest Restoration
Project
Cost: $7-10 Billion
Fig. 11-13, p. 269