Four methods of harvesting fish include:

The use of hook and line: hooks are tied to string and set across water.
The use of nets: this involves the use of various type of nets e.g gill net, trawl net, etc. which are thrown into water for fish haulage.
The use of traps: trap is set in water in order to catch fish.
The draining of ponds: ponds containing fish are drained off in order to harvest matured fish. After harvesting water is allowed into the pond.