Purse Seine
Imagine trying to gather all your loose change that has scattered around the bottom of your bag. Similar to how you might use your hands to form a makeshift barrier to scoop up the coins, a purse seine uses a net to encircle and capture fish. Just like your hands create a barrier with a weighted bottom (your palms) and a buoyant top (your fingers curving upward), the purse seine net has a weighted edge that sinks to form a wall in the water and a buoyed top edge that floats, efficiently gathering fish inside.
Practice Version
Purse Seine: A fishing method using a net that hangs in the water with weighted bottom edge and top edge buoyed by floats. Purse seine is a large wall of netting that encircles schools of fish and is then drawn tight at the bottom to capture them.