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Fishing in the 21st Century The 3 Major (commercial) Technologies: Longlining Trawling Gill (Drift) Netting Other Technologies Purse Seining Open-water Aquaculture Harpooning Traps and pots Ponds Hook&Line Trolling The Big Picture

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the 3 major commercial technologies
The 3 Major (commercial) Technologies:



Gill (Drift) Netting

other technologies
Other Technologies

Purse Seining




Traps and pots




the big picture
The Big Picture
  • Up to Yr 2000, increased tech & effort resulted in increased catch
  • Global catch increased 500% btwn 1950-1997
  • Peaked in 1997 at 96 million tons
  • Nature article: actually peaked in 1987 at about 80 million tons

Reg Watson* & Daniel Pauly*; Nature, Nov 01

example shark catch off hawaii 1991 2001
Example: Shark Catch off Hawaii: 1991-2001

Source: NFWS government statistics

example 2 billfish catch
Example 2: Billfish Catch

Source: NOAA Fisheries

some scary long line stats
Some scary Long-line Stats:
  • Longlining most prevalent technology used
  • Estimated 2 billion longline hooks set each year
  • Once caught 10 fish for 100 hooks set. Now, 1 per 100.
  • Bycatch includes 40,000 turtles and 200,000 birds/year

Mother Jones, March 2006

the issues with trawling
The issues with Trawling
  • Levels seafloor 150x that of clearcuts yearly Mother Jones, March 2006
  • Before and after pics of trawling
  • Deep sea corals and sponges are long-lived and important to habitat structure
  • In one trawl-pass in AK, 2200 lbs of coral was collected
  • Source: NOAA,
drift gill nets
Drift (Gill) Nets

Lost monofilament nets don’t decompose & become “ghost nets” that continue to kill for years

A young Right Whale (1 of 300) died last month in gillnet gear. NOAA banned all gillnets until the end of March (breeding season) source: MSNBC, 2006

CFG banned gillnets to 60 fathoms in CA from Point Reyes to Santa Barbara to protect sea otters and birds. Defenders of

the major issues
The Major Issues:



Habitat damage:

  • Bycatch: unwanted catch usually dead or dying thrown overboard
  • Globally: 25% of total catch
  • For each lb of shrimp, 2-10 lbs of bycatch
  • Bycatch of dolphins in tuna industry led to consumer boycotts and the “dolphin safe” label
  • Turtle bycatch led to the use of TEDs in US shrimp fishery


Shrimp bycatch


habitat damage
Habitat Damage
  • Broad term for habitat issues. Includes:
    • Bottom destruction from trawling
    • Pollution from land and water
    • Loss of wetlands/mangroves, etc due to development/farming

Phuket island, Thailand. Dark red on coasts represents mangroves. Source: Gov of Thailand

  • 1 large bluefin tuna can garner $100,000 on Tokyo fish market
  • 10% of all large fish (tuna, swordfish, marlin, etc) and ground fish (cod, halibut, flouder) remain in world source: Worm & Myers, 2003
  • Long-lived fish:
    • Rockfish (over 200yrs)
    • Orange Roughy (100yrs)
  • Big fish play essential ecological roles: predation and competition create stability and biodiversity source: Hixon, Oregon State University
  • You might think that fish farming is a solution……but
fish aquaculture not all equal
Fish Aquaculture:Not all Equal
  • Farmed salmon
    • laced with PCBs,
    • require 3lbs of wild fish for each 1lb of salmon,
    • Pass disease to wild salmon
  • Farmed shrimp
    • In Thailand (leading exporter), 60% of mangroves have been eliminated for shrimp farms
    • Mangroves provide habitat for 80% of tropical fish spawning
  • Farmed Tilapia & Catfish
    • Are freshwater fish
    • Farmed in in-land ponds where waste can be processed and disease confined
    • Are herbivorous

Sources: MBAQ, American University, Mother Jones: March 2006

bycatch solutions
Bycatch solutions
  • Pingers protect porpoises. Required on all drift nets in gulf of Maine since 1999
  • Longlining has been done at night when endangered short-tailed albatross are around
  • Source:
habitat solutions
Habitat Solutions
  • In Sept 2005, new bill in house would protect deep sea corals, study bottom trawling more
  • Presidential order in 2000 established Marine Protected Area Center. (More on this later)
overfishing solutions
Overfishing Solutions
  • To end the Tragedy of the Commons.
  • HW: Read “The Catch” from Mother Jones, March 2006