Fishing Methods
• Traditional analogues for modern methods• Spears, arrows• Active traps• Passive traps, fish ponds• Hooks• Active nets• Passive nets• Inland & nearshore subsistence fishing• spears exploding harpoons
Old & New Methods
• Spear• Hook-n-line
• Traps
• Exploding harpoon• Trolling• Trolling-n-chumming• Demersal Trawl line• Pelagic Trawl line• 2000 hooks; 3-4%• Traps• FADs
Nets
• Gill Nets• Floats & weights• Drift nets
– Efficiency– Fiber advances– Bycatch– 33000km—80%– Banned in 1992
• Trawl Nets• demersal & pelagic• Power needed• Beam• beam Otter• 10-100m opening• Echo-sounder• sonar
A comparison between typical trawl catch and a typical gillnet catch associated with the pre-industrial fishing. Note that the cod end of the net on the factory trawler is bigger than the entire boat housing the traditional fisher.
Table 2.2 Major species of fish caught with otter trawls
Species Major fishing countries Areas fished
Alaska pollock Russia, Japan, South Korea Northwestern Pacific
USA Northeastern Pacific
Atlantic cod Iceland, Norway, Russia Northeastern Atlantic
Blue whiting Norway, Iceland, Russia, Faeroe Islands
Northeastern Atlantic
Largehead hairtail China, South Korea Northwestern Pacific
Largehead hairtail (Trichiurus lepturus). Weight to 5 kg, length to 2.3 meters
Purse Seines
• Globally, most fish catch…by far
• Catch fish schooling near surface
• 100km x 100m
• Fish must aggregate in large schools
• Powerful means to deploy & retrieve
• Dories (50’s) to power block
Icelandic freezer trawler Svalbakur, capable of catching 60 tonnes per haul
Purse seine boats beginning a set on a 64-tonne school of Atlantic menhaden in coastal waters of North Carolina.
Table 2.1 Major species of fish caught with purse seines
Species Major fishing countries Areas fished
Atlantic herring Canada, USA, Northwestern Atlantic
Denmark, Iceland, Norway Northeastern Atlantic
capelin Iceland, Norway Northeastern Atlantic
Chilean jack mackerel Chile, Peru Southeastern Pacific
Chub mackerel China, South Korea, Russia Northwestern Pacific
Chile Southeastern Pacific
European pilchard Morocco East Central Atlantic
Japanese anchovy China, Japan, South Korea Northwestern Pacific
Peruvian anchovy Peru Southwestern Pacific
Skipjack tuna Indonesia, Taiwan, Japan, South Korea, Philippines, USA, Palau
West central Pacific
Ecuador Southeastern Pacific
Japan Northwestern Pacific
Spain, Maldives Indian Ocean
Yellowfin tuna Philippines, Taiwan, Japan, USA West Central Pacific
Mexico, Venezeula East central Pacific
Ecuador Southeastern Pacific
France Western Indian
Catch Amount by type
• Purse Seine ~50%– Herring,sardine,anchovies,tuna,mackerel
• Otter Trawl ~17%– Pollock, cod,whiting
• Lines ~ 9%– Tunas,swordfish,cod,halibut,haddock,etc
• Pound/trap nets ~8%– Lobsters,crabs
• Gill Nets ~6%– Squid,salmon,billfish
Technology
• Echo sounders
• Synthetic fibers
• Power
• Boat range
• Preservation of catch– Drying/salting icing,canning,freezing
Artisanal Fishing
A fisherman in Cochin, India
The beachfront market of St.-Louis, Senegal
Fishing technology in Senegal. Wives parcel out the dregs of catches. The best fish are sold to European traders or seafood processors.
Schematic of modern, high-tech fishing vessel. From left to right: purse seine, squid jigger, long liner, trawl net equipped with sonar to automatically track schools of fish. The factory trawler depicted above is the Alaska Ocean. It is capable of processing more than 600 tonnes of pollock per day into surimi, the protein paste used in imitation seafood products.