Chapter 11

1. 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 sustainmarinebiodiversity? • How can we manage and sustain the world’s marine fisheries?

3. Chapter Overview Questions (cont’d) • How can we protect, sustain, and restorewetlands? • How can we protect, sustain, and restorelakes, 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 surfacebecause 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 1.0-2.5 centimeters. • We have destroyed more than 1/3 of the world’s mangrove forests, mostly for shipping lanes. • Shrimp farming is a big, 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 1900-2000. • 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 fishedor 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. 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 Buoy Float 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? • Human ecological footprint is increasing so rapidly • Much damage done to oceans is “invisible” to most people • Most citizens are unaware of the scope and severity of the problems • Lack of legal jurisdiction • 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. Turtle Excluder Devices (TEDs)

28. Turtle Excluder Devices (TEDs)

29. Turtle Excluder Devices (TEDs)

30. Bycatch Reduction Devices (BRDs)

31. Bycatch Reduction Devices (BRDs)

32. 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

33. 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

34. 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

35. 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

36. Toothed whales *Sperm whale with squid Killer whale Narwhal Bottlenose dolphin Baleen whales Blue whale Fin whale Bowhead whale Right whale Sei whale Humpback whale Gray whale *Minke whale Fig. 12-5, p. 258

37. 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.

38. 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.

39. 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.

40. 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, sea turtles, and bycatch fish 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 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

41. 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

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

43. 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

44. 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 Fig. 12-9, p. 264

45. Case Study: Restoring the Florida Everglades

46. Case Study: Restoring the Florida Everglades • The world’s largestecological 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 in nearby coastal waters.

47. 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

48. 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.

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

50. PROTECTING, SUSTAINING, AND RESTORING LAKES AND RIVERS Migrate to “natal stream” Spawn Sept-Nov Sept-Dec In stream gravel Jan-April Mature in ocean 2-5 yrs Emerge May-June Migrate to ocean in April- Aug A few months to 2 years