A cast net is a circular, cone-shaped fishing net with small weights attached to its outer edge and a drawstring( or brail lines) running to a central handline. When thrown by hand, it spreads flat in the air, sinks over a school of fish, and closes at the bottom as it is pulled back.

Advantages 

Captures an entire school of baitfish or small fish in a single throw instead of one by one.

Uses no chemicals, motors . Bycatch( unwanted fish or marine) can usually be released back in water.

its cost effective hence affordable.

It is easily managed by one individual from start to finish.

Ideal for fish farmers doing routine stock health sampling or partial harvesting, as well as scientists estimating fish populations.

Where applicable

It is best used in shallow to moderately deep waters typically ranging from 1 to 4meters, or up to the radius of the net with low vegetation and gentle currents.

Operates in both fresh and saltwater ecosystems globally, through local regulations frequently restrict or ban their use in specific inland zones.