Longlining
Thousands of hooks all fish at once when a longliner rolls out the gear. The central fishing line can be 50 miles long, and it is strung with many smaller lines holding baited hooks. After leaving the lines to "soak" for a time to attract fish, longline fishermen return to haul in their catch. Pelagic longlining takes place near the sea surface, targeting midwater fishes like swordfish and tuna. Demersal or "bottom" longlining targets fishes that live closer to the seafloor, like cod, halibut and sablefish.
 
Source:
Monterrey Bay Aquarium
Conservation and Research
Seafood Watch