Más contenido relacionado


Más de College of Fisheries, KVAFSU, Mangalore, Karnataka(20)


Threats to marine biodiversity

  1. Threats to marine biodiversity
  2. Fig. 12-A, p. 255 Fish farming in cage Trawler fishing Spotter airplane Sonar Trawl flap Trawl lines Purse-seine fishing Trawl bag Fish school Drift-net fishing Long line fishing Lines with hooks Fish caught by gills Deep sea aquaculture cage Float Buoy
  3. Biodiversity • Variety of living things, number of kinds • Ecological diversity – different habitats, niches, species interactions • Species diversity – different kinds of organisms, relationships among species • Genetic diversity – different genes & combinations of genes within populations
  4. Benefits of Biodiversity • New food sources – Grains, fruits, vegetables, meat, fish 4
  5. Benefits of Biodiversity • Medicines • Plants • Jellyfish & sea anemones • Nudibranchs • Marine slugs 5
  6. Biodiversity • How much biodiversity  1.7—2.0 million species  Estimates to 100 million 6
  7. Protecting Biodiversity 7 • How can we protect biodiversity – Stop overharvesting • Sustainable yield • Hunting & fishing laws (every state ?) – in developing nations ? – Protect habitat • Refuges, parks, preserves – Endangered Species Act
  8. Protecting Biodiversity • Refuges, parks, preserves – How big should refuges be? – Where should they be? – McArthur & Wilson “Theory of Island Biogeography” • colonization rate • extinction rate (local) • predicts number of species 8
  9. Protecting Biodiversity • Endangered Species Act (1973) – Goal to “recover” species so they no longer need protection under ESA – Implements U.S. participation in CITES • “Convention on International Trade in Endangered Species” • Prohibits trade in listed species – whole organisms – parts: skins, bones, teeth, flowers, leaves, etc. • Other laws: – Marine Mammal Protection Act – Migratory Bird Treaty Act – Anadromous Fish Conservation Act – etc. 9
  10. In broad terms, the living inhabitants of the marine realm face five major threats: • Changes to oceanic temperatures, acidity and patterns of water movement (including currents, eddies and fronts), largely caused by increasing atmospheric carbon dioxide, as well as impacts from damage to the ozone layer; climate change:
  11. • overfishing with attendant bycatch problems, both from commercial fishing, recreational fishing, illegal unregulated or unreported fishing (IUU), and ghost fishing. • habitat damage largely caused by fishing gear, especially bottom trawling, but also including the effects of coastal development: destruction of coral reefs, mangroves, natural freshwater flows (and passage), coastal foreshores, coastal wetlands and sometimes entire estuaries – which all support coastal marine ecosystems; overfishing habitat damage
  12. • pollution (in-sea and land-based, diffuse and point source) including nutrients, sediments, plastic litter, noise, hazardous and radioactive substances; discarded fishing gear, microbial pollution, and trace chemicals such as carcinogens, endocrine- disruptors, and info-disruptors; and • ecosystem alterations caused by the introduction of alien organisms, especially those transported by vessel ballast water and hull fouling. pollution ecosystem alterations
  13. The core impacts of climate change are caused by: • An increase in the temperature of ocean waters - causing, for example, coral bleaching (Veron 2008); • the increase in the acidity of ocean waters, causing a rising aragonite saturation horizon, particularly in the North Pacific and Southern Ocean.
  14. Important reviews of pollution in the marine environment are provided by: • Nutrients – a general review: Rabalais (2005– in the Caribbean: • plastic litter – Derraik (2002); Goldberg (1997) • noise –Firestone & Jarvis (2007); NRC (2005 • radioactive waste – Koslow (2007) • heavy metals – Islam & Tanaka (2004) • discarded fishing gear – Matsuoka et al. (2005); Brown (2007) • microbial pollution – Islam & Tanaka (2004) • endocrine disruptors –Porte et al. (2006) • other hazardous materials – Islam & Tanaka (2004); Koslow (2007).
  15. Threats to Marine Biodiversity • Eutrophication • Effects of contaminants • Habitat degradation, fragmentation and destruction • Fishing and especially trawling • Climate Change Habitat Degradation
  16. Reclamation (= coastal habitat destruction) Threats to Marine Biodiversity
  17. Threats to Marine Biodiversity; Trawling
  18. A full trawl Picture from Greenpeace Web site Threats to Marine Biodiversity; Trawling Above: Before Trawling; Below: After Trawling
  19. Important papers on marine and estuarine habitat damage include: • Estuaries and rivers – Ray (1996, 2004, 2005), Drinkwater & Frank (1994); • Impacts of bottom trawling –Gray et al. (2006), Jones (1992), • Coral ecosystems – Aronson & Precht (2006), Jackson et al. (2001), • mangroves – Duke et al. (2007), Ellison & Farnsworth (1996); • seagrasses – Orth et al. (2006), • kelp –Dayton et al. (1998).
  20. Threats and controls: Threats Controls Overfishing and bycatch Restricted entry to fishery, catch quotas, limits or requirements on gear, limits on fishing seasons, limits on fishing areas, no- take areas, prohibitions on dumping or discarding gear. Attempts to reduce or eliminate government subsidies contributing to fishing over-capacity. Control by flag States of high seas fishing particularly in regard to compliance with international and regional fishing agreements. Market-based fishery accreditation systems such as that of the Marine Stewardship Council. Government control programs based on minimising ecosystem effects Surveillance and compliance programs including VMS.
  21. Habitat damage Limits on gear, limits on fishing areas, no-take areas. Fixed mooring systems in sensitive (eg coral) environments. Surveillance and compliance programs. Land-based zoning schemes combined with project assessment and approval provisions aimed at minimising the loss of coastal habitat resulting from land-based developments. Special protection for high conservation value estuaries. Zoning of key migration rivers to exclude dams, weirs and other impediments to fish passage. Protection of the catchment of high conservation value estuaries and rivers to maintain natural water flows and water quality.
  22. Climate change International agreements, such as those focussed on greenhouse gasses or chlorofluorocarbons or (eg: the Kyoto Protocol, Montreal Protocol) - and the implementation programs which follow, including incentives, prohibitions and market-based schemes aimed at reducing GG emissions. Pollution Controls focussed on fixed point sources, mobile point sources and diffuse terrestrial sources – including dumping and emissions to air and water . Controls on marine noise. Controls focused on specific pollutants, such as plastics or highly toxic or radio-active substances. Integrated coastal and river basin planning, including objectives to limit the passage of nutrients and other pollutants to the marine environment. Surveillance and compliance programs.
  23. Biodiversity Hotspots (Myers et al 2000 Nature)
  24. Tropical cone snails contain toxins which show promise for treating some forms of cancer and heart irregularities. One toxin may be a thousand times more potent than morphine for pain relief. But millions of cone snails are now killed annually for their shells, and their habitats are under pressure. Cone snail from the Pacific Ocean. Biodiversity Losses = Loss of Services & Potential Helpful Products
  25. How can we prevent biodiversity loss? •Research •Legislation •Education/Awareness •Sustainable use of habitats and fisheries •Integration/Co-ordination
  26. Marine Protection Areas (MPA’s) are used to…..  Nationally / internationally to conserve biodiversity.  Manage natural resources.  Protect endangered species.  Reduce user conflict.  Provide educational and research opportunities.  Enhance commercial and recreational activities.
  27. Marine Protected Areas  Marine Protected Areas are used as management tools to protect, maintain, or restore natural and cultural resources in coastal and marine waters.
  28. Kinds of Marine Protected Areas 1. National marine sanctuaries. 2. Fishery management zones. 3. National seashores. 4. National parks/ monuments. 5. Critical habitats. 6. National Wildlife refuges. 7. National estuarine research reserves. 8. State conservation areas. 9. State reserves.
  29. What do MPA’s protect? Aggregations Habitat important to valuable fisheries Sea Turtle nesting areas. Endangered Species
  30. What do MPA’s protect? ShipwrecksCoral reef habitats
  31. The End