A purse seine is a large wall of netting deployed around an entire area or school of fish.
The seine has floats along the top line with a lead line threaded through rings along the bottom. Once a school of fish is located, a skiff encircles the school with the net. The lead line is then pulled in, “pursing” the net closed on the bottom, preventing fish from escaping by swimming downward.
- Purse seines can reach more than 6,500 ft (2,000 m) in length and 650 ft (200 m) in depth, varying in size according to the vessel, mesh size, and target species.
- Finding a school of fish is one of the most difficult steps of this fishing technique and include:
- Natural cues such as a congregation of seabirds, ruffling of surface water and/or fast moving groups of dolphins.
- Helicopters scanning the water for natural cues from the air to direct boats toward schooling fish.
- Using radar fish finders to help identify the exact location and size of a school.
There are other types of catching salmon such as gill netting and trolling employed in Alaska and other American coastal waters.