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Chapter 11: Sustaining Aquatic Biodiversity

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1 Chapter 11: Sustaining Aquatic Biodiversity
The coastal zone may be the single most important portion of our planet. The loss of biodiversity may have repercussions far beyond our worst fears. – G. Carelton Ray

2 Case Study: Protecting Whales: A Success Story… So Far (1)
Cetaceans: Toothed whales and baleen whales 8 of 11 major species hunted to commercial extinction by 1975 1946: International Whaling Commission (IWC) Quotas based on insufficient data Quotas often ignored Figure 11.1: Cetaceans are classified as either toothed whales or baleen whales.

3 Case Study: Protecting Whales: A Success Story… So Far (2)
1970: U.S. Stopped all commercial whaling Banned all imports of whale products 1986: IWC moratorium on commercial whaling 42,480 whales killed in 1970 1500 killed in 2009 Norway, Japan, and Iceland ignore moratorium

4 11-1 What Are the Major Threats to Aquatic Biodiversity?
Concept Aquatic species are threatened by habitat loss, invasive species, pollution, climate change, and overexploitation, all made worse by the growth of the human population.

5 We Have Much to Learn about Aquatic Biodiversity
Greatest marine biodiversity Coral reefs Estuaries Deep-ocean floor Biodiversity is higher Near the coast than in the open sea In the bottom region of the ocean than the surface region

6 Natural Capital: Marine Ecosystems
Figure 8.5: Marine systems provide a number of important ecological and economic services (Concept 8-2). Questions: Which two ecological services and which two economic services do you think are the most important? Why? Fig. 8-5, p. 172

7 Natural Capital: Freshwater Systems
Figure 8.15: Freshwater systems provide many important ecological and economic services (Concept 8-4). Questions: Which two ecological services and which two economic services do you think are the most important? Why? Fig. 8-15, p. 181

8 Human Activities Are Destroying and Degrading Aquatic Habitats
Marine Coral reefs Mangrove forests Seagrass beds Sea-level rise from global warming will harm coral reefs and low-lying islands with mangrove forests Ocean floor: effect of trawlers Freshwater Dams Excessive water withdrawal

9 Natural Capital Degradation: Area of Ocean Bottom Before and After a Trawler
Figure 11.2: Natural capital degradation. These photos show an area of ocean bottom before (left) and after (right) a trawler net scraped it like a gigantic bulldozer. These ocean-floor communities could take decades or centuries to recover. According to marine scientist Elliot Norse, “Bottom trawling is probably the largest human-caused disturbance to the biosphere.” Trawler fishers disagree and claim that ocean bottom life recovers after trawling. Question: What land activities are comparable to this? Fig. 11-2, p. 252

10 Invasive Species Are Degrading Aquatic Biodiversity
Threaten native species Disrupt and degrade whole ecosystems Two examples Asian swamp eel: waterways of south Florida Lionfish in the Atlantic

11 Invasive Lionfish Figure 11.3: One scientist has described this common lionfish as “an almost perfectly designed invasive species.” It reaches sexual maturity rapidly, has large numbers of offspring, and is protected by venomous spines. In the eastern coastal waters of North America, it has few if any predators, except perhaps for people. It is hoped that commercial fishers can find ways to capture lionfish economically and that consumers will choose them from seafood menus. Fig. 11-3, p. 254

12 Science Focus: How Carp Have Muddied Some Waters
Lake Wingra, Wisconsin (U.S.): eutrophic Contains invasive species Purple loosestrife and the common carp  eat algae which stabilize sediment  fish movements & wind cause turbidity Dr. Richard Lathrop Removed carp from an area of the lake This area appeared to recover  native plants receive more sunlight

13 Lake Wingra in Madison, Wisconsin
Figure 11.A: Lake Wingra in Madison, Wisconsin (USA) has become clouded with sediment partly because of the introduction of invasive species such as the common carp. Removal of carp in the experimental area shown here resulted in a dramatic improvement in the clarity of the water and subsequent regrowth of native plant species in shallow water. Fig. 11-A, p. 255

14 Case Study: Invaders Have Ravaged Lake Victoria
Loss of biodiversity and cichlids Nile perch: deliberately introduced Frequent algal blooms Nutrient runoff Spills of untreated sewage Less algae-eating cichlids Water hyacinths: supported by nutrient runoff

15 Natural Capital Degradation: The Nile Perch In Lake Victoria
Figure 11.4: Natural capital degradation. The Nile perch (right) is a fine food fish that can weigh more than 91 kilograms (200 pounds). However, this deliberately introduced fish has played a key role in a major loss of biodiversity in East Africa’s Lake Victoria (left). Fig. 11-4a, p. 254

16 Water Hyacinths in Lake Victoria
Figure 11.5: Invasive water hyacinths, supported by nutrient runoff, blocked a ferry terminal on the Kenyan shores of Lake Victoria in By blocking sunlight and consuming oxygen, this invasion has reduced biodiversity in the lake. Scientists reduced the problem at strategic locations by removing the hyacinth and by introducing two weevils (a type of beetle) that feed on the invasive plant. Fig. 11-5, p. 255

17 Population Growth and Pollution Can Reduce Aquatic Biodiversity
More noise and crowding from humans Nitrates and phosphates, mainly from fertilizers, enter water Leads to eutrophication Toxic pollutants from industrial and urban areas Plastics

18 Hawaiian Monk Seal Figure 11.6: This Hawaiian monk seal was slowly starving to death before a discarded piece of plastic was removed from its snout. Each year, plastic items dumped from ships and garbage barges, and left as litter on beaches threaten the lives of millions of marine mammals, turtles, and seabirds that ingest, become entangled in, or are poisoned by such debris. Fig. 11-6, p. 256

19 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, and New York City

20 Overfishing and Extinction: Gone Fishing, Fish Gone (1)
Fishery: concentration of a particular wild aquatic species suitable for commercial harvesting in a specific area Fishprint: area of ocean needed to sustain the fish consumption of a person, country, or the world Marine and freshwater fish Threatened with extinction by human activities more than any other group of species


22 Overfishing and Extinction: Gone Fishing, Fish Gone (2)
Commercial extinction: no longer economically feasible to harvest a species Collapse of the Atlantic cod fishery and its domino effect Fewer larger fish More problems with invasive species

23 Natural Capital Degradation: Collapse of the Cod Fishery Off the Canadian Coast
Figure 11.7: Natural capital degradation. This graph illustrates the collapse of Canada’s 500-year-old Atlantic cod fishery off the coast of Newfoundland in the northwest Atlantic. Beginning in the late 1950s, fishers used bottom trawlers to capture more of the stock, reflected in the sharp rise in this graph. This resulted in extreme overexploitation of the fishery, which began a steady decline throughout the 1970s, followed by a slight recovery in the 1980s, and then total collapse by 1992, when the fishery was shut down. Despite a total ban on fishing, the cod population has not recovered. The fishery was reopened on a limited basis in 1998 but then closed indefinitely in 2003 and today shows no signs of recovery. (Data from Millennium Ecosystem Assessment) Fig. 11-7, p. 257

24 Science Focus: Clashing Scientific Views Can Lead to Cooperation and Progress
Ray Hilborn disagreed Boris Worm with about the long-term prognosis for the world’s fisheries The two agreed to work together Developed new research methods and standards Examined maximum sustained yield Reported findings and prognosis in 2009

25 Case Study: Industrial Fish Harvesting Methods
Trawler fishing Purse-seine fishing Longlining Drift-net fishing Bycatch problem Figure 11.8: This diagram illustrates several major commercial fishing methods used to harvest various marine species (along with methods used to raise fish through aquaculture). These fishing methods have become so effective that many fish species have become commercially extinct.

26 11-2 How Can We Protect and Sustain Marine Biodiversity?
Concept We can help to sustain marine biodiversity by using laws and economic incentives to protect species, setting aside marine reserves to protect ecosystems, and using community-based integrated coastal management.

27 Legal Protection of Some Endangered and Threatened Marine Species (1)
Why is it hard to protect marine biodiversity? Human ecological footprint and fishprint are expanding Much of the damage in the ocean is not visible The oceans are incorrectly viewed as an inexhaustible resource Most of the ocean lies outside the legal jurisdiction of any country

28 Legal Protection of Some Endangered and Threatened Marine Species (2)
1975 Convention on International Trade in Endangered Species 1979 Global Treaty on Migratory Species U.S. Marine Mammal Protection Act of 1972 U.S. Endangered Species Act of 1973 U.S. Whale Conservation and Protection Act of 1976 1995 International Convention on Biological Diversity

29 Economic Incentives Can Be Used to Sustain Aquatic Biodiversity
Tourism Sea turtles Whales Economic rewards

30 Case Study: Holding Out Hope for Marine Turtles
Threats to the leatherback turtle Trawlers and drowning in fishing nets Hunting Eggs used as food Pollution Climate change Fishing boats using turtle excluder devices Communities protecting the turtles

31 Sea Turtle Species Figure 11.9: Several major species of sea turtles have roamed the sea for 150 million years. The hawksbill, Kemp’s ridley, and leatherback turtles are critically endangered. Flatbacks live along the coasts of northern Australia and Papua, New Guinea, and are not classified as endangered because they nest in very remote places, but the Australian government classifies them as vulnerable. The loggerhead, green, and olive ridley are classified as endangered. See the photo of an endangered green sea turtle on the title page. Fig. 11-9, p. 262

32 An Endangered Leatherback Turtle is Entangled in a Fishing Net
Figure 11.10: This endangered leatherback sea turtle was entangled in a fishing net and could have starved to death had it not been rescued. Fig , p. 262

33 Marine Sanctuaries Protect Ecosystems and Species
Offshore fishing Exclusive economic zones for countries 200 nautical miles High seas governed by treaties that are hard to enforce Law of the Sea Treaty Marine Protected Areas (MPAs)

34 Establishing a Global Network of Marine Reserves: An Ecosystem Approach (1)
Closed to Commercial fishing Dredging Mining and waste disposal Core zone No human activity allowed Less harmful activities allowed E.g., recreational boating and shipping

35 Establishing a Global Network of Marine Reserves: An Ecosystem Approach (2)
Fully protected marine reserves work fast Fish populations double Fish size grows Reproduction triples Species diversity increase by almost one-fourth Cover less than 1% of world’s oceans Marine scientists want 30-50%

36 Protecting Marine Biodiversity: Individuals and Communities Together
Oceans 30% more acidic from increased carbon dioxide in atmosphere and increased temperature

37 11-3 How Should We Manage and Sustain Marine Fisheries?
Concept Sustaining marine fisheries will require improved monitoring of fish and shellfish populations, cooperative fisheries management among communities and nations, reduction of fishing subsidies, and careful consumer choices in seafood markets.

38 Estimating and Monitoring Fishery Populations Is the First Step
Maximum sustained yield (MSY): traditional approach Optimum sustained yield (OSY) Multispecies management Large marine systems: using large complex computer models Precautionary principle

39 Some Communities Cooperate to Regulate Fish Harvests
Community management of the fisheries Co-management of the fisheries with the government Government sets quotas for species and divides the quotas among communities Limits fishing seasons Regulates fishing gear

40 Government Subsidies Can Encourage Overfishing
Governments spend billion dollars per hear subsidizing fishing Often leads to overfishing Discourages long-term sustainability of fish populations

41 Consumer Choices Can Help to Sustain Fisheries and Aquatic Biodiversity
Need labels to inform consumers how and where fish was caught 1999: Marine Stewardship Council (MSC) Certifies sustainably produced seafood Proper use of sustainable aquaculture Plant eating fish best -- Tilapia

42 Solutions: Managing Fisheries
Figure 11.11: There are a number of ways to manage fisheries more sustainably and protect marine biodiversity. Questions: Which four of these solutions do you think are the most important? Why? Fig , p. 267

43 11-4 How Should We Protect and Sustain Wetlands?
Concept To maintain the ecological and economic services of wetlands, we must maximize preservation of remaining wetlands and restoration of degraded and destroyed wetlands.

44 Coastal and Inland Wetlands Are Disappearing around the World
Highly productive wetlands Provide natural flood and erosion control Maintain high water quality; natural filters Effect of rising sea levels

45 We Can Preserve and Restore Wetlands
Laws for protection Zoning laws steer development away from wetlands In U.S., need federal 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

46 Human-Created Wetland in Florida
Figure 11.12: This human-created wetland is located near Orlando, Florida (USA). Fig , p. 268

47 Case Study: Can We Restore the Florida Everglades? (1)
“River of Grass”: south Florida, U.S. Damage in the 20th century Drained Diverted Paved over Nutrient pollution from agriculture Invasive plant species 1947: Everglades National Park unsuccessful protection project

48 Case Study: Can We Restore the Florida Everglades? (2)
1990: Comprehensive Everglades Restoration Plan (CERP) 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 Recapture Everglades water flowing to sea and return it to Everglades Already weakened by Florida legislature

49 The World’s Largest Restoration Project
Figure 11.13: The world’s largest ecological restoration project is an attempt to undo and redo an engineering project that has been destroying Florida’s Everglades (USA, see photo) and threatening water supplies for south Florida’s rapidly growing population. Fig , p. 269

50 11-5 How Should We Protect and Sustain Freshwater Lakes, Rivers, and Fisheries?
Concept Freshwater ecosystems are strongly affected by human activities on adjacent lands, and protecting these ecosystems must include protection of their watersheds.

51 Freshwater Ecosystems Are under Major Threats
Think: HIPPCO 40% of world’s rivers are dammed Many freshwater wetlands destroyed Invasive species Threatened species Overfishing Human population pressures

52 Case Study: Can the Great Lakes Survive Repeated Invasions by Alien Species?
Collectively, world’s largest body of freshwater Invaded by at least 162 nonnative species Sea lamprey Zebra mussel Quagga mussel Asian carp

53 Zebra Mussels Attached to a Water Current Meter in Lake Michigan
Figure 11.14: These zebra mussels are attached to a water current meter in Lake Michigan. This invader entered the Great Lakes through ballast water dumped from a European ship. It has become a major nuisance and a threat to commerce as well as to biodiversity in the Great Lakes. Fig , p. 271

54 Asian Carp from Lake Michigan
Figure 11.15: According to U.S. Environmental Protection Agency, two species of Asian carp were close to invading Lake Michigan in If they become established in Lake Michigan, they are likely to spread rapidly and disrupt the food web that supports the lakes’ native fish populations. Eventually, they could become the dominant fish species in the interconnected Great Lakes. Fig , p. 271

55 Managing River Basins Is Complex and Controversial
Columbia River: U.S. and Canada Snake River: Washington state, U.S. Dams Provide hydroelectric power Provide irrigation water Hurt salmon

56 Natural Capital: Ecological Services of Rivers
Figure 11.16: Rivers provide some important ecological services. 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 to sustain them. Questions: Which two of these services do you believe are the most important? Why? Fig , p. 272

57 We Can Protect Freshwater Ecosystems by Protecting Watersheds
Freshwater ecosystems protected through Laws Economic incentives Restoration efforts Wild rivers and scenic rivers 1968 National Wild and Scenic Rivers Act

58 11-6 What Are the Priorities for Sustained Biodiversity, Ecosystem Services?
Concept Sustaining the world’s aquatic biodiversity requires mapping it, protecting aquatic hotspots, creating large, fully protected marine reserves, protecting freshwater ecosystems, and carrying out ecological restoration of degraded coastal and inland wetlands.

59 Using an Ecosystem Approach to Sustaining Aquatic Biodiversity
Edward O. Wilson Complete the mapping of the world’s aquatic biodiversity Identify and preserve aquatic diversity hotspots Create large and fully protected marine reserves Protect and restore the world’s lakes and rivers Ecological restoration projects worldwide Make conservation financially rewarding

60 Three Big Ideas The world’s aquatic systems provide important ecological and economic services, and scientific investigation of these poorly understood ecosystems could lead to immense ecological and economic benefits. Aquatic ecosystems and fisheries are being severely degraded by human activities that lead to aquatic habitat disruption and loss of biodiversity.

61 Three Big Ideas We can sustain aquatic biodiversity by establishing protected sanctuaries, managing coastal development, reducing water pollution, and preventing overfishing.

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