Shellfish Trap Mechanics

[aptson]

Could anyone please explain to me how the shellfish trap mechanics work in depth?

[Tulgarath]

Build a trap on land, place it in deep water. Place food, grass, meat etc in the trap to lure shellfish.

The purity of the catch will match the net purity used in creating the trap.

There are spawns of shellfish, fresh water and salt water. Supposedly, the better the bait, the better the odds of catching something.

Pretty low maintenance way to catch shell fish.

Anyone else want to fill in the gaps?