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Fisheries

Explore challenges and solutions in managing fisheries to ensure long-term sustainability and alleviate malnutrition. Learn about valuable marine resources, seafood products, bycatch issues, and effective fisheries management practices.

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Fisheries

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  1. Fisheries 015

  2. http://www.pbs.org/emptyoceans/

  3. Traditional food production 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 ?

  4. Most valuable living marine resources: • Demersal fish • Pelagic fish • Crustaceans • Mollusks • Marine mammals

  5. Location of the world’s major commercial fisheries coastal areas upwelling

  6. Commercial fishing: • 500 species 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

  7. Global Fish Catch

  8. World Commercial Catch of 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

  9. Food & Non-Food Products from the Sea

  10. Non-Food Products from the Sea • Bioactive Compounds • Algin & Agar: products from seaweed • Whales: Oil for lubrication, in cosmetics, bones for fertilizer • Seals and sea lions: furs

  11. Food from the Sea • Seaweeds • Invertebrates (e.g., oysters, clams, crabs, lobster, squid, etc.) • Fish (herring, mackerel, haddock, cod, tuna, mahi-mahi, etc.) • Whales

  12. Fisheries management • Fisheries management 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

  13. Fisheries Mismanagement

  14. Fisheries mismanagement • Overfishing • Commercial extinction • Bycatch (27 million metric tons annually) • Targeting smaller species on the low end of the food chain

  15. Bycatch by Gear Type for 2002/2003

  16. Euphausia superba

  17. Who eats Krill?

  18. Krill & the Antarctic Food Web Critical components of Antarctic food webs

  19. Krill Fishery • Annual consumption by natural predators = 470 million MT • 1972: Japan and Russia began harvesting krill

  20. Krill Fishery… • Potential harvest = 25-30 million MT/yr • Economic cost of fishery high • Patchy distribution complicates location • Depths may be 150-200m • Single net haul may collect 10 MT • Ecological consequences of removal poorly understood

  21. Peru Anchovy Fishery

  22. 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

  23. Peru Anchovy Fishery = El Niño 1957 1965 1972 1976 1982-83

  24. Peru Anchovy Fishery Normal Year El Niño Year

  25. Collapse of New England 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

  26. Collapse of New England 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

  27. Fisheries Management Council The Magnuson Act created 8 regional fisheries management councils for U.S. waters and regions: New England FMC (Saugus, MA) Mid-Atlantic FMC (Dover, DE) South Atlantic (Charleston, SC) Gulf of Mexico FMC (Tampa, FL) Caribbean (San Juan, PR) North Pacific FMC (Anchorage, AK) Pacific FMC (Portland, OR) Western Pacific FMC (Honolulu, HI)

  28. Fisheries Management Plans Congress directed the Councils to manage federal fisheries by creating Fisheries Management Plans or “FMPs” by: 1. Identifying fish species that need management 2. Analyzing the biological, environmental, economic and social factors that affect the fishery 3. Preparing (and modifying, as necessary) an FMP to protect fishery resources while maintaining opportunities for domestic commercial and recreational fishing

  29. Salmon • Anadromous fish that migrate from sw to fw to spawn • Spawning grounds affected by dam construction • Aquaculture and restocking efforts

  30. Fish Ladders

  31. Alaska Fisheries • Halibut and sablefish • IFQ • Limited entry c1930’s

  32. Shark Overfishing • Slow growth • Low reproductive rate • Late sexual maturity

  33. 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

  34. Fishing Techniques

  35. 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

  36. Drift Net net size: 20 m x 65 km

  37. Longlining

  38. Gill net Bottom-dwelling fish

  39. Purse seine

  40. Trawl bottom midwater http://www.youtube.com/watch?v=bUHcD_jTgVA

  41. Before trawl After trawl

  42. Trawl from space Gulf of 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)

  43. Laws of the Sea Treaty Allow nations to claim jurisdiction over their territorial seas (contiguous sea beds and their waters that extend off shore by 12 nautical miles) • Exclusive Economic Zone (EEZ) • 200 nautical miles • under direct control of the country that owns the nearest land • Regulates continental shelf resources: • Fishing • Mineral exploration • Scientific research

  44. Exclusive Economic Zone of the United States

  45. Fisheries Problems & Solutions

  46. Fisheries Problems & Solutions • Maximum sustainable yield: maximum amount of fish that can be harvested without depleting future stocks • World‘s maximum sustainable yield estimated at 100 to 135 million metric tons • Present harvests are at about 100 million metric tons • For fisheries where numbers available, estimated that 45% are currently over-fished • A number of fisheries have already collapsed (Anchovy fishery off Peru, Cod fishery in the N. Atlantic)

  47. 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

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