Fisheries notes

Marine Science Educator
11 de Nov de 2013

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Fisheries notes

  1. Fisheries Always keep in mind that fish are a “Common Property Resource”
  2. Fish Stocks • The actual number of fish • Sometimes the area and the species are defined Ex: “The Atlantic Coast Striped Bass Stocks are stronger than they were in the 1980’s” • Other times people use the word in a general sense
  3. EEZ • The US Exclusive Economic Zone is claimed out from our shores to 200 miles out to sea • The US maintains that this region is ours, exclusively to use and no other country is allowed here without our permission • We use our EEZ for things like fisheries, military uses, oil drilling, mining, etc.
  4. Mechanisms of Harvesting Fish
  5. Mechanisms of Harvesting Fish • Hook and Line (AKA Pole Fishing) • Bottom Trawl • Gillnetting • Jigging • Longlining • Harpooning • Trolling • Traps & Pots • Seine Net • Purse Seine Net • Watch methods here:
  6. Animal Husbandry • Aquaculture = growing or raising aquatic animals • Mariculture= growing or raising aquatic animals in the ocean
  7. Bycatch (AKA Trash Fish) • Animals captured while fishing that are not the targeted species and are frequently thrown back dead or dying • Examples: -Sea Turtles in the Shrimp Fishery -Dolphin in the Tuna Industry -You may be familiar with Sea Robins as bycatch in recreational fluke fishing
  8. More on Bycatch • The Bad News…For every pound of shrimp you consume, up to 20 pounds of bycatch is thrown back, much of it dead • The Good News…Consumers can speak with their wallets to encourage change within the industry: • TED’s (Turtle Excluder Devices) & BRD’s (Bycatch Reduction Devices)
  9. How TEDs and BRDs work In the top diagram the trawl net has no BRD fitted. All animals that enter the net are caught in the cod end, including prawns, turtles and unwanted fish species. In the bottom diagram, the trawl net has two types of BRD fitted. The turtle excluder device stops turtles from entering the cod end and forces them out through a flap on the trawl net. Because fish have a tendency to swim against a current, the fish eye allows them to swim out through the top of the net and avoid capture in the cod end. Even with BRDs fitted, prawns are still caught in the cod end.
  10. Overfishing • So if we don’t let other countries into our EEZ, why do we still have trouble with overfishing? – We, ourselves, are taking too many fish – Fish don’t know boundaries • Why do we fish further and further from our coasts? – We are taking our coastal fish at a more rapid rate than they can replenish
  11. Factors contributing to Decline in Fish Stocks • • • • • • • Long range fishing vessels Factory ships Airplane spotters Huge nets SONAR More demand by consumers Habitat destruction
  12. Overfished Stocks in the US (as of 2010)
  13. Other Frequently Used Fishery Management Vocabulary • MSY: Maximum Sustainable Yield – the highest number of fish people can harvest and still allow the fish population to grow • In theory, at MSY catch should = reproduction rate • If catch < reproduction the population should grow • If catch > reproduction the population will decrease Can you see any problems with this theory?
  14. Strategies for Conservation • Size Limits: used when we want fish to have a chance to grow, reproduce. Ex: 28” • Catch (bag) limits: establish how many can be taken in a given time frame. ex: Two fish per day • Closed areas: establish no-take areas. ex: Spawner Sanctuaries & MPA’s (Marine Protected Areas). ex: Nature Conservancy property in GSB, LI and MPA’s in CA
  15. Strategies for Conservation cont. • Gear restrictions: limit the ways people can harvest. ex: No trawling allowed, trap fishing only • Seasons: limit time frame for harvesting. Ex: No harvesting during breeding season • Licensing: limit the number of fishing licenses given out • Sex limits: limit harvest on a particular sex (Note: this only works if species is sexually dimorphic)
  16. Other Conservation Techniques • Protect what fishery managers call “Essential Fish Habitat” – Spawning grounds – Nursery grounds – Feeding habitats • Conduct “Multispecies Management” – Protect the whole food web of the fish you want to conserve (their food, their food’s food, etc.)
  17. Magnuson – Stevens Fishery & Management Act • Named after senators from Washington state and Alaska who sought to more appropriately exploit fisheries in our EEZ • Originated in 1976 • Last revised in 2007 (see next slide)
  18. Most updated Magnuson – Stevens Fishery Conservation & Management Act goals, paraphrased: • • • • • • • • • • Prevent overfishing while achieving optimum yield. Use best scientific information available. Manage stocks as a unit throughout their range; manage interrelated stocks as a unit or in close coordination. Not discriminate between residents of different states; any allocation of privileges must be fair & equitable. Promote efficiency, except that no such measure shall have economic allocation as its sole purpose. Take into account & allow for variations among & contingencies in fisheries, fishery resources, & catches. Minimize costs & avoid duplications. Take into account the importance of fishery resources to fishing communities to provide for the sustained participation of, & minimize adverse impacts to, such communities (consistent with conservation requirements). Minimize bycatch or mortality from bycatch. Promote safety of human life at sea
  19. Agencies • Federal: – NMFS: National Marine Fisheries Service – USFWS: United States Fish & Wildlife Service – EPA: Environmental Protection Agency • States: – NYSDEC: New York State Department of Environmental Conservation (1) • – ASMFC: Atlantic States Marine Fisheries Commission (1) • – MAFMC: Mid-Atlantic Fishery Management Council (8)
  21. Reminder: Fisheries Managers deal with a very dynamic living resource AND people who may not have the same ideas about sharing this resource Watch the videos on this site and be prepared to discuss in class: