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Water Use. Fishing Techniques. Bottom Trawling Drift Nets Long Lines Purse Seine. Overfishing. Statistics 52% of fish stock fully exploited 16% overexploited 8% depleted Oceans viewed as unlimited resources Ocean productivity is low Light restricted to surface. Overfishing.

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Presentation Transcript
fishing techniques
Fishing Techniques
  • Bottom Trawling
  • Drift Nets
  • Long Lines
  • Purse Seine
overfishing
Overfishing
  • Statistics
    • 52% of fish stock fully exploited
    • 16% overexploited
    • 8% depleted
  • Oceans viewed as unlimited resources
  • Ocean productivity is low
    • Light restricted to surface
overfishing1
Overfishing
  • Supply 1% of food, represents 10% of protein
  • 1/3 of catch used for other purposes than food
    • Fish oil, fish meal, animal feed
  • 1/3 of global catch is bycatch
    • Discarded catch – sea turtles, marine mammals, shellfish
maximum sustainable yield
Maximum Sustainable Yield
  • Highest rate of use that can be matched by replacement
  • Maximum that can be caught without causing population to crash
  • Generally occurs at ½ carrying capacity
maximum sustainable yield1
Maximum Sustainable Yield
  • How does it work?
  • How to determine it?
managing fisheries
Managing Fisheries
  • Regulate locations of fish farms and monitor pollution
  • Encourage production of herbivorous fish
  • Label products to indicated raised or caught by sustainable methods
  • Set catch limits below MSY
  • Prevent importation if not caught using sustainable methods
  • Increase marine sanctuaries and no-fishing areas
  • Monitor and destroy invasive species
  • Ban throwing back bycatch
aquaculture
Aquaculture
  • Commercial growing of aquatic organisms for food
    • Stocking, feeding, protecting, harvesting
aquaculture1
Aquaculture
  • Growing about 6% annually
  • Provides 5% of total food production
  • Most common products – seaweeds, mussels, oysters, shrimp, certain fish (salmon, trout, catfish)
aquaculture2
Aquaculture
  • Problems
international whaling
International Whaling
  • Heavily depleted until 1980s
  • 1974 International Whaling Commission (IWC)
  • 1986 IWC enacted moratorium on all whaling
coral reefs
Coral Reefs
  • Most diverse and biologically productive ecosystems
  • Corals (animal) have a mutualistic relationship with photosynthetic algae (zooxanthellae)
  • Generate $375 billion in tourism and fishing revenue
coral reefs1
Coral Reefs
  • Bleaching
  • Exploitation
mangroves
Mangroves
  • Often located inland of coral reefs
  • Trees have ability to root and grow in shallow marine sediments
mangroves1
Mangroves
  • Services
mangroves2
Mangroves
  • Damage
    • Coastal development
    • Logging
    • Shrimp aquaculture
      • Mangrove is cleared
      • Land bulldozed to make shallow ponds
      • Black tiger prawns grown in ponds ($multibillion industry)
      • Pond becomes polluted  shrimp no longer grow  new ponds created, old ponds are flushed and pollution damages adjacent coastal environments
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