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Fisheries

Fisheries. 026A. http://www.pbs.org/emptyoceans/. Traditional food production and distribution practices are unable to feed the world’s 7+ billion people Will resources in the sea be able to provide enough food to alleviate future problems of malnutrition and starvation ?.

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Fisheries

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  1. Fisheries 026A

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

  3. Traditional food production and distribution practices are unable to feed the world’s 7+ 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 management • Management was based on maximum sustained yield.

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

  16. Bycatch by Gear Type for 2002/2003

  17. Peru Anchovy Fishery

  18. 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

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

  20. Peru Anchovy Fishery Normal Year El Niño Year

  21. 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

  22. 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

  23. 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)

  24. 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

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

  26. Fish Ladders

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

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

  29. 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

  30. Fishing Techniques

  31. 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

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

  33. Longlining

  34. Gill net Bottom-dwelling fish

  35. Purse seine

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

  37. Before trawl After trawl

  38. 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)

  39. Fisheries Problems & Solutions

  40. 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)

  41. 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

  42. 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 Dolphins caught in tuna net

  43. Fisheries Problems & Solutions Driftnets: indiscriminate entangling of many sorts of marine animals SOLUTION: banned in oceanic fisheries (but some countries still using them)

  44. 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.

  45. We are “fishing down the food chain” • As fishing increases, the size and age of fish caught decline.

  46. Global swordfish catch Ave. wt. in lbs http://www.pifsc.noaa.gov/wpacfin/hi/dar/Pages/hi_fish_2.php year

  47. Mariculture

  48. Mariculture or Aquaculture (marine agriculture)- farming finfish, shellfish and algae under favorable conditions Big Island, Kona, Tilapia

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