Cage traps are versatile, and you can use them for a variety of bottom-dwelling fish. Openings in the metal caging allow fish, crayfish, lobster and crab to enter the baited trap but prevent them from exiting the trap. The cage is connected to a line, which is connected to a buoy and dropped to the floor of the lake, ocean or river. The buoy marks the location and makes it easy to retrieve the trap. The design is simple but effective.
Nets are very effective for trapping fish, and you can use them for gathering large numbers in a single swoop. You can use nets in a variety of ways, including circling, trolling and throwing. Trolling nets is the most common among commercial fisherman, because they can control the depth of the net and trap large numbers of fish. Circling uses nets attached to poles. The nets cutoff a large area. Once the area is isolated, the enclosure is made smaller, until the fish are trapped in a small circle. Throwing nets requires locating a fish-rich area and tossing the net onto a school of fish. The net is weighted at each corner and sinks over the school, trapping the fish.
You can construct functional fish traps with simple household items. One of the most popular types uses a 2-liter soda bottle. You cut off the neck of the bottle, turn it upside down, and place it back in the bottle. You then glue the neck to the bottle and drop rocks in, along with a food source. Hungry fish swim inside of the bottle, but they cannot exit the bottle.