Does anyone know how those underwater crab cages work? I can't figure it out.?

Question

Does anyone know how those underwater crab cages work? I can't figure it out.?

Answer 1

They're set up in such a way that it's easy for the crabs to get in and eat the bait, but harder to get out... http://www.fao.org/docrep/004/x2590e/x25... notice the kinda funnel-shaped entrance holes... very difficult to climb back out of from the inside when you're brain's as small as a crab's.

Answer 2

They're traps. They're used not only for crabs, but also for other crustaceans as well as some fish species.

For animals that live on rocky bottoms where it's impossible to pass a net, these traps are the best option.

There are different models, but basically they consist of a box with a funnel-like entrance.

The trap is placed on the bottom, with some bait inside of it, and attached to a float so that the fishermen know where it is.

It is then left for a given period (may be hours, days, etc).

The animals go into the cage attracted by the bait, but then can't get out.

They are convenient because 1) the type of and size of the animals they catch are quite specific; for instance, individuals that are too small will be able to get away, and 2) the animals remain alive until the trap is collected.

Answer 3

The cage is a square like shape ..one end with a cone construction narrow at the end  with spikes preventing the crab from leaving, the other end fish or other bait are used to lure them in....!!!

On top will be the door to catch the crab when trapped...!!!