Chapter 11

1. Chapter 11 Sustaining Aquatic Biodiversity

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. Marine Biodiversity • #1 is coral reefs • Higher in coastal zone than open sea • Higher on bottom region than surface region b/c of greater habitat variety and food sources

6. HIPPCO • Also applies to marine habitat • Habitat alteration • Trawlers drag nets weighted with heavy chains • Dams and excess water withdrawal

7. Invasives • Water hyacinths in Lake Victoria • Asian Swamp eel can travel over land • Purple loosestrife: introduced from Europe European predators have been introduced

8. Fig. 11-4, p. 252

9. Lake Wingara Introduced carp eat algae that stabilize sediment on lake bottom

10. Fig. 11-A, p. 253

11. Population, Pollution, Climate Change • In ten years, 80% of world population will live near coast • Nitrate runoff continues to increase (fertilizer) • Average sea level rise is 4 – 8 inches in past 100 years • Coral reefs too far from surface • Low lying islands submerged (Maldives: now 5ft above sea level) • Coastal wetlands (and mangroves) may be lost

12. Overfishing • Industrial fishing is unsustainable • Fishprint • Commercial extinction • Newfoundland’s cod fishery is closed (20,000 fishers and processors out of work) • When desirable fish go, small, young fish are target, so little chance for recovery • 1/3 of fish catch is bycatch

13. Commercial Fishing Methods • Sonar, GPS, and huge nets increase yield of commercial operations • 75% of commercial fisheries are fished at or beyond their sustainable yield

14. 3 Fishing Methods • Trawler fishing • Scrape ocean bottom • Huge, some trawler nets can cover 12 jumbo jets • Purse-seine fishing • Used for fish near surface (tuna, dolphin safe?) • Longlining • Up to 80 miles long, thousands of hooks • Can catch sea turtles, dolphins

15. 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

16. Drift Nets • Tennis net with larger weave that may be 40 miles long and 50 feet deep • May break loose and kill fish for years • Fish get caught between threads • Bycatch: unwanted fish, sea birds, sea turtles • UN has banned nets longer that 1.6 miles • Voluntary, hard to monitor

17. TEDs • http://www.youtube.com/watch?v=y71cgxmyMO4

18. Laws and Treaties • CITES • ESA

19. Whales • Cetaceans • Marine mammals • Toothed whales • Feed on squid, etc (porpoise) • Baleen whales • Filter feeders; krill (blue whale) • 8/11 major species commercially extinct

20. Whales • Blue whale near extinction • 25 years to reproductive age, one offspring every 2-3 years • IWC • Since 1970, US banned whaling and imports • Since 1986, international ban has been successful • Japan: scientific purposes - restaurants • Norway defies ban Debate about current population

21. Sea Turtles • 6/7 are endangered • Leatherback has survived 100 million years • Eggs deposited at night on beaches • Babies hatch together and move across beach to the sea • Nets, long line, hunters affect population • Plastic bags • TEDs

22. Fig. 11-10, p. 260

23. Marine Sanctuaries • Offshore fishing limit is 200 statute miles • exclusive economic zone • Marine protected areas (MPAs) • High seas • Marine reserves would include areas in high seas • Population doubles, biodiversity increases • Benefits nearby fisheries • $12-14 billion/year, 1 million jobs

24. CO2 Problems • IUCN indicates coral reefs can survive global warming if overfishing, pollution are curbed • CO2 + water = carbonic acid • Dissolves calcium carbonate shells • Possibly most damaging consequence of increase of CO2 concentration

25. Integrated coastal management • Fishers, business owners, politicians, scientists, citizens develop long term solutions • Great Barrier Reef Marine Park is managed by ICM

26. Fishery Populations • Maximum sustainable yield (MSY) vs optimum sustainable yield (OSY) • OSY takes into account consequences to other species and error

27. Subsidies • Government subsidies encourage overfishing • $30-34 billion given to fishers per year • $10-14 billion encourages overfishing and expansion of industry

28. Individual Transfer Rights • Government gives each fisher a percentage of the total allowable catch (TAC) for a fishery in a year • Worked in Alaska’s halibut fishery • Problems • Private fishers own public water, public pays for system • Monopoly possibility • TACs are usually too high

29. Sustainable Seafood • Certification • Marine Stewardship Council (MSC) • “Fish Forever” ecolabel • Walmart agreed to sell only MSC certified seafood by 2011

30. SOLUTIONS Managing Fisheries Fishery Regulations Bycatch Set catch limits well below the maximum sustainable yield Use wide-meshed nets to allow escape of smaller fish Use net escape devices for seabirds and sea turtles Improve monitoring and enforcement of regulations Ban throwing edible and marketable fish back into the sea Economic Approaches Sharply reduce or eliminate fishing subsidies Aquaculture Charge fees for harvesting fish and shellfish from publicly owned offshore waters Restrict coastal locations for fish farms Control pollution more strictly Protect Areas Depend more on herbivorous fish species Certify sustainable fisheries Establish no-fishing areas Nonnative Invasions Establish more marine protected areas Kill organisms in ship ballast water Rely more on integrated coastal management Filter organisms from ship ballast water Consumer Information Label sustainably harvested fish Dump ballast water far at sea and replace with deep- sea water Publicize overfished and threatened species Fig. 11-12, p. 265

31. Wetlands • In US, more than 50% of 1900 wetlands have been lost • What happened? • Soon, coastal wetlands could be under water • Feeding stops for migratory bird flyways affected • Commercial fish and shellfish populations affected

32. Government can help • Zoning laws could be used to prevent further development • A federal law requires a permit to dump dredged material into wetlands bigger than 3 acres

33. Mitigation Banking • Policy that allows development of a wetland as long as another wetland area is created or restored • Most attempts to create wetlands fail • Why?

34. The Everglades • Originally, 60 mile wide sheet of water flowing from Lake Okeechobee to Florida Bay • Now less than half its original size • In 1948, a water control project was completed • Drained for farmland (sugarcane) • Paved over • Nutrient runoff from ag Biodiversity loss: invasives, habitat loss, fragmentation from urbanization

35. Kissimmee River • Feeds into Lake Ocheechobee • b/w 1962 and 1971, US Army Corps of Engineers straightened the river • Flood control, but • rapid flow of water drained land north of Lake Ocheechobee • Water was diverted for crops and cities, so • Less flow into Florida Bay causes salinity and temperature to increase • More nutrients cause algae bloom

36. Fig. 11-14, p. 268

37. Restoration • In 1990, US and state government agreed to fund restoration project • Among other projects, the Corps of Engineers will restore meandering flow of river • Cost = $10 billion • Sugarcane growers convinced Florida legislature to increase allowable P discharge limit and delay date of implementation of limit

38. Dams • Columbia River in northwest • 119 dams; 19 hydroelectric dams • Interfere with spawning salmon who must return upstream to lay eggs • Population down by 94% • Snake River in Washington State • Similar scenario, environmentalists want small hydroelectric dams taken down