1 / 36

Fisheries

Fisheries. 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 ?. Most valuable living marine resources:

ataret
Download Presentation

Fisheries

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Fisheries

  2. 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 ?

  3. Most valuable living marine resources: • Demersal fish (bottom dwellers) • Pelagic fish (free-swimming mid/upper dwellers) • Crustaceans • Mollusks • Marine mammals

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

  5. Food & Non-Food Products from the Sea

  6. Non-Food Products from the Sea • Bioactive Compounds (drugs and insecticides) • Algin & Agar: products from seaweed use for promoting gel formation • Whales: Oil for lubrication, in cosmetics, bones for fertilizer • Seals and sea lions: furs

  7. Food from the Sea • Seaweeds • Invertebrates (e.g., oysters, clams, crabs, lobster, squid, etc.) • Fish (herring, mackerel, haddock, cod, tuna, mahi-mahi, etc.) • Whales – international moratorium imposed in 1987; no commercial whaling permitted since with limited exceptions

  8. Case Study: 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 and has NEVER recovered

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

  10. Peru Anchovy Fishery

  11. Peru Anchovy Fishery Normal Year El Niño Year

  12. Case Study: 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

  13. Collapse of New England Fisheries • Magnuson-Stevens Act of 1976 prevented foreigners from fishing in U.S. waters • Fishery technology intensified and resulted in overfishing – yields well beyond sustainable levels • Georges Bank closed indefinitely after collapse in ~1994 • Some fish stocks have begun to rebound

  14. Fisheries Management Council The revised Magnuson Act in 2007 created 8 regional fisheries management councils. Overfished stocks as of 2010

  15. Fisheries Management Plans • Congress directed the Councils to create Fisheries Management Plans or “FMPs” for each species • Primarily concerned with balancing growth of stocks with commercial needs • Established annual catch limits or acceptable biological catch • Attempted to end overfishing and help stocks recover • Major critics say that the fisheries are still about to crash and that the Councils are mismanaged and ineffective • Heavily revised in 2010 to be community-based initiatives and saw increased prices with less but more responsible catches as a result in experimental areas

  16. Fishing Techniques

  17. Fishing Methods • Longline – baited hooks (100’s to many thousands) along a long line; used for swordfish, tuna (pelagic); cod, halibut (bottom) • Trolling – many lines with single hooks slowly dragged through the water; use for salmon, albacore, mahi-mahi

  18. Fishing Methods • Drift (gill) netting – vertical nets hung in the water to trap passing fish • highly controversial! • banned by UN, US limits length to ~1.7 miles • used to catch various pelagic fish

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

  20. Fishing Methods • Trawl – large “pouch” dragged through water/across bottom; used for anchovies (pelagic); cod, halibut (bottom) • Purse seine – net is wrapped around a school of surfacing or near surfacing fish; used for sardines, herring, mackerel, tends to accidentally snare any predators like dolphins

  21. Trawl bottom midwater

  22. Before trawl After trawl

  23. Fishing Methods • Traps and Pots - Crabs, lobster, rock fish • Main problem with most methods is “bycatch” – nontarget species caught and usually killed

  24. 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 (230 land miles) • under direct control of the country that owns the nearest land • Regulates continental shelf resources: • Fishing • Mineral exploration • Scientific research

  25. Exclusive Economic Zone of the United States

  26. Mariculture

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

  28. Aquaculture also produces: • Bait fish • Ornamental or aquarium fish • Aquatic animals used to augment natural populations • Algae for chemical extraction • Pearl oysters

  29. Criteria for selecting species for farming: - inexpensive to grow - grows quickly - high sales price - resistant to disease and parasites barramundi catfish tilapia

  30. Problems associated with Mariculture: • Won’t make a dent in the shortfall in food supply • Fish food- fish meal • Pollution • Escapees • High stress overcrowding pens • High concentration of pathogens/parasites

  31. Overcrowded Pens

More Related