1. Sustaining Aquatic Biodiversity
Chapter 12
Sustaining Aquatic Biodiversity

2. Aquatic Biodiversity What do we know?
Only have explored 5% of the oceans
Greatest marine biodiversity occurs in coral reefs, estuaries and deep ocean floor.
Biodiversity is higher by the coast then the open sea
Biodiversity is greater in the bottom region of the ocean then the surface region

3. Aquatic Biodiversity Values of Aquatic Biodiversity
Provide us with an estimated $21 trillion a year
At least 3.5 billion people depend on the oceans for survival
Many marine organisms have chemicals used in medicines
Freshwater systems provide services worth $1.7 trillion.

4. Human Impacts on Aquatic Biodiversity
Loss and degradation
90% of fish living in the oceans spawn in coral reefs, mangroves, coastal wetlands or rivers.
20% of coral reefs have been destroyed. Up to 58% could be lost by 2050.
15% of worlds seagrass beds have disappeared since 1995
Sea level is rising- over the past 100 years level has risen by cm
Mangroves and wetlands have been lost to development
Trawlers are destroying bottom ecosystems

5. Human Impacts on Aquatic Biodiversity
Invasive Species
Blamed for about 2/3 of fish extinctions in the US between 1900 and 2000 and cost an average of $16 million per HOUR.
Most arrive in ballast water
Examples:
Asian swamp eel eats many types of fish. It can withstand cold weather, drought, fires and predators because it can burrow. It can also breath air.

6. Human Impacts on Aquatic Biodiversity
Population Growth and Pollution
% of the worlds population lives on or near a coast.
Estimated that 80% of ocean pollution comes from land based activities
Amount of nitrate fertilizers has doubled since Excess nutrients can cause eutrophication which can lead to algae blooms and then fish die offs.
Toxic pollutants from industrial and urban areas
Plastic pollution kills 1 million seabirds and 100,000 sea turtles.

7. Human Impacts on Aquatic Biodiversity
Overfishing and Extinction
Modern industrialized fishing can deplete marine life very rapidly. Can cause 80% depletion of a target fish species in only years.
Usually leads to commercial extinction.
In 1992 Canada’s cod fishery collapsed. Still has not recovered.
90% of the large open ocean fish have disappeared since 1950
Can cause bycatch – organisms caught unintentionally in nets.

8. Human Impacts on Aquatic Biodiversity
Why is it difficult to protect?
Human ecological footprint is expanding so rapidly that it is difficult to monitor the impacts.
Damage to oceans is not visible to humans
People view the sea as an inexhaustible resource that can absorb an infinite number of pollutants
Most oceans lie outside the legal jurisdiction of any country.

9. Protecting and Sustaining Marine Biodiversity
Legal and economic approaches
1975 CITES
1979 Global Treaty on Migratory Species
US Marine Mammal Protection Act of 1972
US Endangered Species Act of 1973
US Whale and Conservation and Protection Act of 1973
1995 International Convention on Biological Diversity

10. 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
Figure 12-B

11. Case Study: Commercial Whaling
After many of the world’s whale species were overharvested, commercial whaling was banned in 1960, but the ban may be overturned.
Figure 12-6

12. Case Study: 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.
Figure 12-5

13. Protecting and Sustaining Marine Biodiversity
Marine sanctuaries
International law states that a country’s offshore fishing zone extends to 370km (200 miles) from its shores.
Exclusive economic zones:
High seas:
Marine protected areas (MPAs):
Marine reserves:
Works and works fast – fish populations double, fish size grows by a third, fish reproduction triples, species diversity increases by a fourth.

14. Protecting and Sustaining Marine Biodiversity
Less than 0.3% of the world’s ocean area consists of fully protected marine reserves.
Scientist call for 30% of the ocean to become protected marine reserves.
World’s largest marine reserve was created in 2006.
360,000 sq km (140,000 sq miles) surrounding some Hawaiian island.

15. Protecting and Sustaining Marine Biodiversity
Integrated coastal management
Community based effort to develop and use coastal resources more sustainably.
Revamping US Ocean Policy
Develop unified national policy.
Double federal budget for ocean research.
Centralize the National Oceans Agency.
Set up network of marine reserves.
Reorient fisheries management towards ecosystem function.
Increase public awareness.

16. Managing and Sustaining Marine Fisheries
Make better estimates of fish populations.
Traditional approach is to use a maximum sustainable yield (MSY):
Hasn’t been very successful
Optimum sustainable yield (OSY):
Multispecies management:

17. Solutions Managing Fisheries Fishery Regulations
Set catch limits well below the maximum sustainable yield
Improve monitoring and enforcement of regulations
Bycatch
Use wide-meshed nets to allow escape of smaller fish
Use net escape devices for sea birds and sea turtles
Ban throwing edible and marketable fish back into the sea
Economic Approaches
Sharply reduce or eliminate fishing subsidies
Charge fees for harvesting fish and shellfish from publicly owned offshore waters
Certify sustainable fisheries
Aquaculture
Restrict coastal locations for fish farms
Control pollution more strictly
Depend more on herbivorous fish species
Protected Areas
Establish no-fishing areas
Establish more marine protected areas
Rely more on integrated coastal management
Figure 12.7
Solutions: ways to manage fisheries more sustainably and protect marine biodiversity. QUESTION: Which four of these solutions do you think are the most important?
Nonnative Invasions
Kill organisms in ship ballast water
Filter organisms from ship ballast water
Dump ballast water far at sea and replace with deep-sea water
Consumer Information
Label sustainably harvested fish
Publicize overfished and threatened species
Fig. 12-7, p. 261

18. PROTECTING, SUSTAINING, AND RESTORING WETLANDS
US has lost more then ½ of its wetlands since 1900
Louisiana has 40% of US salt marshes. Much is lost due to sinking. Dams and levees block sediment from flowing down Mississippi River that would normally be deposited. Plus, sea level is rising due to climate change.
Federal permits are required now to fill or dredge a wetland. This has help cut he average annual wetland lost by 80% since 1969.
Mitigation banking:

19. PROTECTING, SUSTAINING, AND RESTORING WETLANDS
Requiring government permits for filling or destroying U.S. wetlands has slowed their loss, but attempts to weaken this protection continue.
Figure 12-8

20. Solutions Protecting Wetlands Legally protect existing wetlands
Steer development away from existing wetlands
Use mitigation banking only as a last resort
Require creation and evaluation of a new wetland before destroying an existing wetland
Restore degraded wetlands
Try to prevent and control invasions by nonnative species
Figure 12.9
Solutions: ways to help sustain the world’s wetlands. QUESTION: Which two of these solutions do you think are the most important?
Fig. 12-9, p. 264

21. Case Study: Restoring the Florida Everglades
The world’s largest ecological restoration project involves trying to undo some of the damage inflicted on the Everglades by human activities.
90% of park’s wading birds have vanished.
Other vertebrate populations down 75-95%.
Large volumes of water that once flowed through the park have been diverted for crops and cities.
Runoff has caused noxious algal blooms.

22. Restoring the Florida Everglades
The project has been attempting to restore the Everglades and Florida water supplies.
Figure 12-10

23. PROTECTING, SUSTAINING, AND RESTORING LAKES AND RIVERS
Lakes are difficult to manage and are vulnerable to planned or unplanned introductions of nonnative species.
For decades, invasions by nonnative species have caused major ecological and economic damage to North America’s Great lakes.
Sea lamprey ($15 million/yr for chemical to kill young), zebra mussel ($140 million a year), quagga mussel, Asian carp.

24. PROTECTING, SUSTAINING, AND RESTORING LAKES AND RIVERS
Dams can provide many human benefits but can also disrupt some of the ecological services that rivers provide.
119 dams on Columbia River have sharply reduced (94% drop) populations of wild salmon.
U.S. government has spent $3 billion in unsuccessful efforts to save the salmon.
Removing hydroelectric dams will restore native spawning grounds.

25. 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).

26. Ecological Services of Rivers
Natural Capital
Ecological Services of Rivers
Deliver nutrients to sea to help sustain coastal fisheries
Deposit silt that maintains deltas
Purify water
Renew and renourish wetlands
Provide habitats for wildlife
Figure 12.11
Natural capital: important ecological services provided by rivers. Currently, the services are given little or no monetary value when the costs and benefits of dam and reservoir projects are assessed. According to environmental economists, attaching even crudely estimated monetary values to these ecosystem services would help sustain them. QUESTIONS: Which two of these services do you think are the most important? Which two of these services do you think we are most likely to decline?
Fig , p. 267