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overfishing.ppt
- 2. • Traditional foodproduction and distribution practices are unable to feed the world’s 6.3+ billion people • Will resources in the sea be able to provide enough food to alleviate future problems of malnutrition and starvation ?
- 3. Most valuable livingmarine resources: • Demersal fish • Pelagic fish • Crustaceans • Mollusks • Marine mammals
- 4. Location of theworld’s major commercial fisheries upwelling coastal areas
- 5. Commercial fishing: • 500species regularly caught • Employs 200 million people worldwide • In 2002 the world fishing fleet numbered about four million vessels. In 2005: • 100 million tons taken • $70 billion
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- 8. World Commercial Catchof Marine Fishes, Crustaceans, and Mollusks (1995) cod Species Group Millions of Metric Tons, Live Wt. Herrings, sardines, anchovies 22.0 Jacks, mullets, sauries 11.2 Mollusks 11.0 Cods, hake, haddock 10.6 Redfish, basses, conger eels 7.0 Crustaceans 4.8 Tunas, bonitos, billfish 4.7 Mackerel, snooks, cutlass fishes 4.7 Flounders, halibut, soles 0.9 Miscellaneous marine fishes 17.7 Total (excluding marine mammals) 94.6
- 10. Food from theSea • Seaweeds • Invertebrates (e.g., oysters, clams, crabs, lobster, squid, etc.) • Fish (herring, mackerel, haddock, cod, tuna, mahi-mahi, etc.)
- 11. Fisheries management • Fisheriesmanagement seeks to maintain a long- term fishery by: – Assessing ecosystem health – Determining fish stocks – Analyzing fishing practices – Enforcing catch limits • Fisheries management does not regulate the number of fishing vessels
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- 13. Fisheries mismanagement • Overfishing •Commercial extinction • Bycatch (27 million metric tons annually) • Targeting smaller species on the low end of the food chain
- 14. Bycatch by GearType for 2002/2003
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- 16. Peru Anchovy Fishery •Upwelling zone off Peru • Fishery began 1950 • Greatest fish catches for any single species • Fish exported for domestic animal feed • Fishery collapsed due to El Niño and overfishing
- 17. = El Niño 1957 1965 1972 1976 1982-83 PeruAnchovy Fishery
- 18. Collapse of NewEngland Fisheries • Cod, haddock, ocean perch, herring, mackerel, blue fin tuna • George’s Bank- highly productive, nutrient rich environment • Prior to 1976, Russia, Japan, Norway, & West Germany fished in Georges Bank
- 19. Collapse of NewEngland Fisheries Magnuson Act passed & prevented foreigners from fishing in U.S. waters Fishery technology intensified and resulted in overfishing Harvests were beyond the max. sustainable yield Georges Bank closes after collapse Some fish stocks begin to rebound
- 20. Alaska Fisheries • Halibutand sablefish • IFQ • Limited entry c1930’s
- 21. Shark Overfishing • Slowgrowth • Low reproductive rate • Late sexual maturity
- 22. Orange Roughy • Distribution:world wide, high concentrations in New Zealand • Found: 700-1000m depth • Life span: slow-growing, long-lived, ~150 years • Size: 30-40 cm • Diet: prawns, fish, & squid • Reproductive age: 25-30 years old
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- 25. Fishing Methods • Harpoon- whales, swordfish, bluefin tuna • Pole and line - mahi-mahi and used for tuna extensively in the 50‘s • Longline - swordfish, tuna (pelagic); cod, halibut (bottom) • Trolling - salmon, albacore, mahi-mahi • Drift (gill) netting - various pelagic fish • Trawl - anchovies (pelagic); cod, halibut (bottom) • Purse seine - sardines, herring, mackerel • Traps and Pots - Crabs, lobster, rock fish
- 26. Drift Net net size: 20m x 65 km
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- 32. Trawl from space Gulfof Mexico, near Louisiana coast. Individual vessels can be seen as bright spots at end of sediment trails. Other bright spots are fixed oil and gas production platforms. One sediment trail can be traced for 27 km. Assuming a standard trawling speed of 2.5 knots, sediment from this trawl is visibly persistent for nearly 6 hours. Water depth <20m. Large, indistinct bright blue patches at lower left and upper right are cloud/haze. (Credit: Landsat)
- 33. Exclusive Economic Zone(EEZ) 1. 200 nautical miles 2. under direct control of the country that owns the nearest land Allow nations to claim jurisdiction over their territorial seas (contiguous sea beds and their waters that extend off shore by 12 nautical miles) Regulates continental shelf resources: • Fishing • Mineral exploration • Scientific research
- 34. Exclusive Economic Zoneof the United States
- 37. Fisheries Problems &Solutions A. Maximum sustainable yield: maximum amount of fish that can be harvested without depleting future stocks B. World‘s maximum sustainable yield estimated at 100 to 135 million metric tons C. Present harvests are at about 100 million metric tons D. For fisheries where numbers available, estimated that 45% are currently over-fished E. A number of fisheries have already collapsed (Anchovy fishery off Peru, Cod fishery in the N. Atlantic)
- 38. Fisheries Problems &Solutions F. Bycatch (or bykill): animals unintentionally killed during harvest of the target species Trawling: Bycatch in shrimp trawling is very high (125 to 830% of the catch is discarded as bycatch), turtles often caught in trawls. SOLUTION: trawls with trap doors to let turtles escape
- 39. Dolphins caught intuna net Purse seine: Tuna known to hang out under pods of dolphins, nets set around pods of dolphins would result in many drowning. SOLUTIONS: Nets not set around dolphin pods and/or employ — “backing down”, a technique that lowers upper edge of net letting dolphins escape
- 40. Fisheries Problems &Solutions Driftnets: indiscriminate entangling of many sorts of marine animals SOLUTION: banned in oceanic fisheries (but some countries still using them)
- 41. Fisheries Problems &Solutions Long lining: Many albatross drown trying to snatch bait from long lines being deployed. snagged on hooks and pulled under. SOLUTION: deploy in the dark or with special rig to let line out under water.
- 42. Global swordfish catch http://www.pifsc.noaa.gov/wpa cfin/hi/dar/Pages/hi_fish_2.php 0 50 100 150 200 250 300 350 400 450 18171861 1900 1961 N. Atlantic Swordfish Ave. wt. in lbs year
- 44. Mariculture or Aquaculture (marineagriculture)- farming finfish, shellfish and algae under favorable conditions Big Island, Kona, Tilapia
- 45. One of everyfour fish eaten today was raised in either a fw or sw fish farm.
- 46. 84% of the6 million to 7 million tons of seafood consumed each year in the U.S. is imported . About ½ comes from aquaculture. H. Jones, Time, 2011.
- 49. Aquaculture also produces: •Bait fish • Ornamental or aquarium fish • Aquatic animals used to augment natural populations • Algae for chemical extraction • Pearl oysters
- 50. Criteria for selectingspecies for farming: - inexpensive to grow - grows quickly - high sales price - resistant to disease and parasites tilapia barramundi catfish
- 51. Problems associated withMariculture: • Won’t make a dent in the shortfall in food supply • Fish food- fish meal • Pollution • Escapees • Loss of natural habitat • Loss of genetic diversity • High stress overcrowding pens • High concentration of pathogens/parasites
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- 53. Salmon with lice Parasites& Disease
- 54. Pollution Under asalmon farm cage
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- 57. Hawaii open oceanaquaculture Mio, big eye tuna, yellow tail $34.7 million in 2008
- 58. Artificial Reefs Improve thelocal marine bio-density 1. attract schools of fish 2. providing habitats for the colonization of commercially valuable species 3. improve the local inshore marine harvest May wash up on beaches tires ship wrecks construction rubble
- 59. Threat to MarineLife • Commercial fishing operations • Pollution • Habitat Degradation • Trampling and beach combing • Climate Change
- 60. Threat to MarineLife • Commercial fishing operations – Overfishing – Discards – Bycatch – Ghost fishing – Use of deleterious fishing gears
- 61. Threat to MarineLife Overfishing –
- 62. Threat to MarineLife Overfishing –
- 63. Threat to MarineLife Discards
- 64. Threat to MarineLife Bycatch
- 65. Cod End ofTrawl Net Threat to Marine Life Use of small mesh
- 66. Threat to MarineLife Deleterious fishing
- 67. Threat to MarineLife Deleterious fishing gears in Nursery
- 68. Threat to MarineLife Deleterious fishing gears in Nursery
- 69. Threat to MarineLife High bycatch
- 70. Threat to MarineLife Non Target Species
- 71. Threat to MarineLife Non Target Species
- 72. Threat to MarineLife • Pollution – Sewage Pollution • Domestic sewage • Industrial sewage – Oil Pollution – Solid waste disposal – Thermal Pollution – Light Pollution
- 73. Threat to MarineLife Sewage Pollution
- 74. Threat to MarineLife Sewage Pollution
- 75. Threat to MarineLife Sewage Pollution
- 76. Threat to MarineLife Oil Pollution
- 77. Threat to MarineLife Oil Pollution
- 78. Threat to MarineLife Solid Waste Disposal
- 79. Threat to MarineLife Thermal Pollution
- 80. Threat to MarineLife Light Pollution: Gwader by night
- 81. Threat to MarineLife • Habitat Degradation – Mangrove denudation – Land reclamation – Port Development
- 82. Threat to MarineLife Mangrove denudation
- 83. Threat to MarineLife Land reclamation
- 84. Threat to MarineLife Port Development-Sonmiani (Damb)
- 85. Threat to MarineLife • Trampling and beach combing – Trampling – Stone turning – Disturbance to animals – Beach Combing
- 86. Threat to MarineLife Trampling
- 87. Threat to MarineLife Disturbance to Marine Animals
- 88. Threat to MarineLife • Climate Change – Seawater intrusion – Frequent cyclone – Unpredictability of weather – Sea Level Rise
- 89. Threat to MarineLife Frequent Cyclone – 2A Cyclone 1999
- 90. Threat to MarineLife Frequent Cyclone – Increased Frequency
- 91. Threat to MarineLife Seawater Intrusion: Indus Creeks
- 92. Threat to MarineLife Frequent Cyclone- Phet Damage at Jiwani
- 93. Threat to MarineLife Sea level Rise-Damb 2006
- 94. Threat to MarineLife Sea level Rise-Damb- 2012
- 97.