If you just let the traps sit for several days, minnows or tadpoles will enter, get stuck and die. That attracts the crayfish which will come and feast on their carcasses. Zero effort, very simple - works for me every time. Any decent population of crayfish should be sampled even in unbaited traps.

Many men go fishing all of their lives without knowing that it is not fish they are after. ~ Henry David Thoreau

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