1. Sustaining Aquatic Biodiversity
Chapter 11
Mola Mola!
Sustaining Aquatic Biodiversity

2. Chapter Overview Questions
What do we know about aquatic biodiversity, and what is its economic and ecological importance?
How are human activities affecting aquatic biodiversity?
How can we protect and sustain marine biodiversity?
How can we manage and sustain the world’s marine fisheries?

3. Chapter Overview Questions (cont’d)
How can we protect, sustain, and restore wetlands?
How can we protect, sustain, and restore lakes, rivers, and freshwater fisheries?

4. Core Case Study: A Biological Roller Coaster Ride in Lake Victoria
Lake Victoria has lost many of its endemic fish species to large introduced predatory fish, the Nile perch.
Figure 12-1

5. Lake Victoria Cichlids
About 200 of 400 Lake Victoria endemic cichlid species have become extinct since the introduction of the Nile perch.
Pundamilia nyererei
Astatotilapia latifasciata
Haplochromis sp. 44 "Red Tail"
Figure 12-1

6. Core Case Study: A Biological Roller Coaster Ride in Lake Victoria
Reasons for Lake Victoria’s loss of biodiversity:
Introduction of Nile perch.
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 (!)

7. AQUATIC BIODIVERSITY
We know fairly little about the biodiversity of the world’s marine and freshwater systems.
We know more about deep space than the abyssal zones of the ocean (why?).
The greatest marine biodiversity occurs in coral reefs, estuaries and the deep ocean floor.
Biodiversity is higher near the coast and surface because of habitat and food source variety.
The world’s marine and freshwater systems provide important ecological and economic services.

8. AQUATIC BIODIVERSITY
Indonesian fishing prau
About 50% of the world’s people depend on the sea as their primary source of food.
Lake Victoria fishers
Georgia shrimper

9. AQUATIC BIODIVERSITY
About 90% of fish spawn in the world’s coral reefs, mangrove swamps, coastal wetlands, or rivers.

10. Coastal Wetlands: Salt marsh or Mangroves

11. Coastal Wetlands: Salt marsh or Mangroves

12. Coastal Wetlands: Salt marsh or Mangroves
Snook!

13. Kayaking Mangroves

14. Kayaking Mangroves

15. Kayaking Mangroves

16. HUMAN IMPACTS ON AQUATIC BIODIVERSITY
Human activities have destroyed, disrupted or degraded a large proportion of the world’s coastal, marine and freshwater ecosystems.
Approximately 20% of the world's coral reefs have been destroyed.
During the past 100 years, sea levels have risen centimeters.
We have destroyed more than 1/3 of the world’s mangrove forests for shipping lanes.
Shrimp farming is a new threat to mangroves

17. HUMAN IMPACTS ON AQUATIC BIODIVERSITY
Area of ocean before and after a trawler net passed by.
Note: East coast shrimp trawlers work in relatively open areas and do not do this much damage
Figure 12-2

18. HUMAN IMPACTS ON AQUATIC BIODIVERSITY
Harmful invasive species are an increasing threat to marine and freshwater biodiversity.
Bioinvaders are blamed for about 2/3 of fish extinctions in the U.S. between
Almost half of the world’s people live on or near a coastal zone and 80% of ocean water pollution comes from land-based human activities.

19. Population Growth and Pollution
Each year plastic items dumped from ships and washing in to the ocean from land threaten marine life.
“Red tide” is a toxic algae bloom that is exacerbated by excess nutrients entering the water from terrestrial sources
Figure 12-3

20. Population Growth and Pollution: Excess Nutrients
Since 1860, humans have doubled the flow of nitrogen, mostly as nitrate fertilizers, into the ocean.
N P K
Potassium
“potash”
Nitrogen
Phosphorous
Figure 12-3

21. Overfishing and Extinction: Gone Fishing, Fish Gone
About 75% of the world’s commercially valuable marine fish species are over fished or fished near their sustainable limits.
Big fish are becoming scarce.
Smaller fish are next.
We throw away 30% of the fish we catch (bycatch)
We needlessly kill sea mammals and birds.

22. Overfishing and Extinction: Gone Fishing, Fish Gone
Commercial depletion occurs when a species has been over fished to the point where it is no longer profitable as a fishery.

23. Overfishing and Extinction: Gone Fishing, Fish Gone
Review! When too many people using the same resource in a way that makes sense for them as individuals results in the collapse of the resource, it is called…
The Tragedy of the Commons

24. Drift-net fishing a.k.a. gill netting
Trawler fishing
Fish farming in cage
Spotter airplane
Sonar
Trawl flap
Trawl lines
Purse-seine fishing
Fish school
Trawl bag
Drift-net fishing a.k.a. gill netting
Long line fishing
Float
Buoy
Figure 12.A
Natural capital degradation: major commercial fishing methods used to harvest various marine species. These methods have become so effective that many fish species have become commercially extinct.
Lines with hooks
Deep sea aquaculture cage
Fish caught by gills
Fig. 12-A, p. 255

25. Why is it Difficult to Protect Aquatic Biodiversity?
Rapid increasing human impacts, the invisibility of problems, citizen unawareness, and lack of legal jurisdiction hinder protection of aquatic biodiversity.
Human ecological footprint is expanding.
Much of the damage to oceans is not visible to most people.
Many people incorrectly view the oceans as an inexhaustible resource.

26. PROTECTING AND SUSTAINING MARINE BIODIVERSITY
Laws, international treaties, and education can help reduce the premature extinction of marine species.
Since 1989 the U.S. government has required offshore shrimp trawlers to use turtle exclusion devices (TEDs)
Sea turtle tourism brings in almost three times as much money as the sale of turtle products.

27. PROTECTING AND SUSTAINING MARINE BIODIVERSITY
Six of the world’s seven major turtle species are threatened or endangered because of human activities.
*beach development
*harvesting eggs
*turtle shell jewelry
*leather made of flippers
Figure 12-4

28. 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

29. 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.
Japan has a significant whaling industry and whale meat market
Figure 12-6

30. 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

31. *Sperm whale with squid
Toothed whales
*Sperm whale with squid
Killer whale
Narwhal
Bottlenose dolphin
Baleen whales
Blue whale
Fin whale
Bowhead whale
Right whale
Figure 12.5
Natural capital: examples of cetaceans, which can be classified as either toothed whales or baleen whales.
Sei whale
Humpback whale
Gray whale
*Minke whale
Fig. 12-5, p. 258

32. How Would You Vote?
To conduct an instant in-class survey using a classroom response system, access “JoinIn Clicker Content” from the PowerLecture main menu for Living in the Environment.
Should carefully controlled commercial whaling be resumed for species with populations of 1 million or more?
No. The hunting of whales is no longer necessary and simply encourages disrespect for these intelligent giants.
Yes. Some whale species have recovered and products from them are valuable resources for humans.

33. PROTECTING AND SUSTAINING MARINE BIODIVERSITY
Fully protected marine reserves make up less than 0.3% of the world’s ocean area.
Marine Reserves Work:
Studies show that in protected areas:
fish populations double
fish size grows by almost a third
reproduction triples
species diversity increases by almost one fourth.
Some communities work together to develop integrated plans for managing their coastal areas.

34. Revamping Ocean Policy
Two recent studies called for an overhaul of U.S. ocean policy and management.
Create a National Oceans Agency within the Executive Office of the President
Develop unified national policy.
Double federal budget for ocean research.
Set up network of marine reserves.
Reorient fisheries management towards ecosystem function.
Increase public awareness.

35. MANAGING AND SUSTAINING MARINE FISHERIES
There are a number of ways to manage marine fisheries more sustainably and protect marine biodiversity.
Some fishing communities regulate fish harvests on their own and others work with the government to regulate them.
Modern fisheries have weakened the ability of many coastal communities to regulate their own fisheries.

36. 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?
NON-NATIVE 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

37. 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

38. PROTECTING, SUSTAINING, AND RESTORING WETLANDS
The US has lost more than 50% of our original wetlands
Figure 12-8

39. PROTECTING, SUSTAINING, AND RESTORING WETLANDS
Mitigation banking allows wetlands to be developed as long as an equal area of wetland is created or restored
At least 50% of wetland mitigation projects fail
Mitigation has worked in Coastal Georgia salt marshes
Figure 12-8

40. 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

41. Case Study: Restoring the Florida Everglades

42. 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.
Large volumes of water that once flowed through the park have been diverted for crops and cities.
90% of park’s wading birds have vanished.
Other vertebrate populations down 75-95%.
Runoff has caused noxious algal blooms.

43. Restoring the Florida Everglades
The the US Army Corps of Engineers has been attempting to restore the Everglades and Florida water supplies.
Figure 12-10

44. 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, zebra mussel, quagga mussel, Asian carp.

45. Columbia River: Former (Future?) Salmon Habitat

46. PROTECTING, SUSTAINING, AND RESTORING LAKES AND RIVERS
Migrate to “natal stream”
Spawn Sept-Nov
Sept-Dec
In stream gravel Jan-April
Mature in ocean yrs
Emerge May-June
Migrate to ocean in April- Aug
A few months to 2 years

47. PROTECTING, SUSTAINING, AND RESTORING LAKES AND RIVERS

48. 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 (economic implications?)

49. How Would You Vote?
To conduct an instant in-class survey using a classroom response system, access “JoinIn Clicker Content” from the PowerLecture main menu for Living in the Environment.
Should federal efforts to rebuild wild salmon populations in the Columbia River Basin be abandoned?
a. No. Restoring salmon populations is critical for the environmental health of the river and surrounding forests.
b. Yes. The restoration program would create unnecessary and severe economic hardships for local residents.

50. 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).

51. National Wild and Scenic Rivers Act
2% of US rivers remain free flowing
0.2% of US rivers are protected by the Wild and Scenic Rivers Act
Vermillion River, IL
Smith River, CA

52. National Wild and Scenic Rivers Act
Skagit River, North Cascade Mountains, WA

53. National Wild and Scenic Rivers Act
Wild Rivers- untamed and inaccessible except by trail; no widening, straightening, dredging, filling, or damming; no motor boats allowed
Scenic Rivers- of great scenic value and accessible by a few roads; free of dams, mostly undeveloped; no motor boats allowed
Recreational Rivers- easily accessible; may have some dams or shore development; motor boats allowed.

54. Reconciliation Ecology: Living with other species
With only 5% of the earth currently protected, we need to learn to live WITH other species
Reconciliation ecology focuses on establishing and maintaining new habitats to maintain biodiversity in places where people live, work, and play

55. Reconciliation Ecology
Protect butterflies and bees (critical pollinators)
Communities agree to reduce use of pesticides on lawns, fields, golf courses, and parks
Neighborhoods work together to plant gardens of flowering plants to support pollinator populations
Build bee and butterfly habitats

56. Reconciliation Ecology
Maintain bat boxes for control of flies and mosquitos

57. Reconciliation Ecology
Growing rooftop gardens
Provides habitat
Saves energy
Provides insulation
Cools cities
Conserves water

58. Rooftop Garden Design

59. 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

60. Updates Online
The latest references for topics covered in this section can be found at the book companion website. Log in to the book’s e-resources page at to access InfoTrac articles.
InfoTrac: Green to the gills. Paul Greenberg. The New York Times Magazine, June 18, 2006 p54(L).
InfoTrac: Net losses. H. Bruce Franklin. Mother Jones, March-April 2006 v31 i2 p54(4).
InfoTrac: Fish and your health. Lynn Keiley. Mother Earth News, April-May 2006 i215 p128(4).
Sustainable Ecosystems Institute
Marine Protected Areas
USGS: Coastal Ecosystems

61. Video: Whaling, Overfishing, Fishery Management
This video clip is available in CNN Today Videos for Environmental Science, 2004, Volume VII. Instructors, contact your local sales representative to order this volume, while supplies last.