Sustaining Aquatic Biodiversity

1. Sustaining Aquatic Biodiversity Chapter 11

2. Core Case Study: A Biological Roller Coaster Ride in Lake Victoria • Loss of biodiversity and cichlids • Nile perch: deliberately introduced • Frequent algal blooms • Nutrient runoff • Spills of untreated sewage • Less algae-eating cichlids

3. Lake Victoria Is a Large Lake in East Africa

4. Natural Capital Degradation: The Nile Perch

5. 11-1 What Are the Major Threats to Aquatic Biodiversity? • Concept 11-1 Aquatic species are threatened by habitat loss, invasive species, pollution, climate change, and overexploitation, all made worse by the growth of the human population.

6. 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

7. Human Activities Are Destroying and Degrading Aquatic Habitats • Habitat loss and degradation • Marine • Coastal • Ocean floor: effect of trawlers • Freshwater • Dams • Excessive water withdrawal

8. Natural Capital Degradation: Area of Ocean Bottom Before and After a Trawler

9. Invasive Species Are Degrading Aquatic Biodiversity • Invasive species • Threaten native species • Disrupt and degrade whole ecosystems • Three examples • Water hyacinth: Lake Victoria (East Africa) • Asian swamp eel: waterways of south Florida • Purple loosestrife: indigenous to Europe • Treating with natural predators—a weevil species and a leaf-eating beetle—Will it work?

10. Invasive Water Hyacinths

11. Science Focus: How Carp Have Muddied Some Waters • Lake Wingra, Wisconsin (U.S.): eutrophic • Contains invasive species • Purple loosestrife and the common carp • Dr. Richard Lathrop • Removed carp from an area of the lake • This area appeared to recover

12. Lake Wingra in Madison, Wisconsin (U.S.)

13. Population Growth and Pollution Can Reduce Aquatic Biodiversity • Nitrates and phosphates mainly from fertilizers enter water • Leads to eutrophication • Toxic pollutants from industrial and urban areas

14. Hawaiian Monk Seal

15. 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

16. Science Focus: Protecting and Restoring Mangroves • Protect and restore mangroves • Reduce the impact of rising sea levels • Protect against tropical storms and tsunamis • Cheaper than building concrete sea walls • Mangrove forests in Indonesia

17. Overfishing and Extinction: Gone Fishing, Fish Gone • Marine and freshwater fish • Threatened with extinction by human activities more than any other group of species • Commercial extinction • Collapse of the cod fishery and its domino effect • Bycatch

18. Natural Capital Degradation: Collapse of the Cod Fishery Off the Canadian Coast

19. 900,000 800,000 700,000 600,000 500,000 Fish landings (tons) 400,000 1992 300,000 200,000 100,000 0 1900 1920 1940 1960 1980 2000 Year Fig. 11-6, p. 254

20. Case Study: Industrial Fish Harvesting Methods • Trawler fishing • Purse-seine fishing • Longlining • Drift-net fishing

21. Major Commercial Fishing Methods Used to Harvest Various Marine Species

22. Trawler fishing Fish farming in cage Spotter airplane Purse-seine fishing Sonar Drift-net fishing Long line fishing Float Buoy lines with hooks Deep sea aquaculture cage Fish caught by gills Fig. 11-7, p. 256

23. Trawler fishing Sonar Drift-net fishing Long line fishing Float Buoy lines with hooks Fish caught by gills Fish farming in cage Spotter airplane Purse-seine fishing Deep sea aquaculture cage Stepped Art Fig. 11-7, p. 256

24. 11-2 How Can We Protect and Sustain Marine Biodiversity? • Concept 11-2 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.

25. Legal Protection of Some Endangered and Threatened Marine Species • 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

26. Case Study: Protecting Whales: A Success Story… So Far • Cetaceans: Toothed whales and baleen whales • 1946: International Whaling Commission (IWC) • 1970: U.S. • Stopped all commercial whaling • Banned all imports of whale products • 1986: moratorium on commercial whaling • Pros • Cons

27. Examples of Cetaceans

28. Fig. 11-8a, p. 258

29. Toothed whales Sperm whale with squid Killer whale Narwhal Bottlenose dolphin 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 Meters Fig. 11-8a, p. 258

30. Fig. 11-8b, p. 258

31. Baleen whales Blue whale Fin whale Bowhead whale Right whale Sei whale Humpback whale Gray whale Minke whale 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 Meters Fig. 11-8b, p. 258

32. Baleen whales Toothed whales Sperm whale with squid Blue whale Killer whale Narwhal Fin whale Bottlenose dolphin Bowhead whale 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 Meters Right whale Sei whale Humpback whale Gray whale Minke whale 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 Meters Stepped Art Fig. 11-8a, p. 258

33. Norwegian Whalers Harpooning a Sperm Whale

34. Economic Incentives Can Be Used to Sustain Aquatic Biodiversity • Tourism • Economic rewards • Reconciliation ecology

35. Case Study: Holding Out Hope for Marine Turtles • Carl Safina, Voyage of the Turtle • Studies of the leatherback turtle • Threats to the leatherbacks • Trawlers • Pollution • Climate change • Communities protecting the turtles

36. An Endangered Leatherback Turtle is Entangled in a Fishing Net

37. Individuals Matter: Creating an Artificial Coral Reef in Israel • Reuven Yosef, Red Sea Star Restaurant • Coral reef restoration • Reconciliation ecology • Treatment of broken coral with antibiotics

38. Marine Sanctuaries Protect Ecosystems and Species • Offshore fishing • Exclusive economic zones • High seas • Law of the Sea Treaty • Marine Protected Areas (MPAs)

39. Establishing a Global Network of Marine Reserves: An Ecosystem Approach (1) • Marine reserves • 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

40. 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

41. Protecting Marine Biodiversity: Individuals and Communities Together • Integrated Coastal Management • Community-based group to prevent further degradation of the ocean

42. An Atoll of Australia’s Great Barrier Reef

43. Video: Humpback whales

44. Video: Loggerhead turtles

45. 11-3 How Should We Manage and Sustain Marine Fisheries? • Concept 11-3 Sustaining marine fisheries will require improved monitoring of fish populations, cooperative fisheries management among communities and nations, reduction of fishing subsidies, and careful consumer choices in seafood markets.

46. 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

47. Some Communities Cooperate to Regulate Fish Harvests • Community management of the fisheries • Comanagement of the fisheries with the government

48. Government Subsidies Can Encourage Overfishing • 2007: World Trade Organization, U.S. • Proposed a ban on fishing subsidies • Reduce illegal fishing on the high seas and in coastal waters • Close ports and markets to such fishers • Check authenticity of ship flags • Prosecution of offenders

49. Some Countries Use the Marketplace to Control Overfishing • Individual transfer rights (ITRs) • Control access to fisheries • New Zealand and Iceland • Difficult to enforce • Problems with the ITR approach

50. Consumer Choices Can Help to Sustain Fisheries and Aquatic Biodiversity • 1997: Marine Stewardship Council (MSC), London • Supports sustainable fishing • Certifies sustainably produced seafood • Manage global fisheries more sustainably • Individuals • Organizations • Governments