Always check local regs before collecting native animals..below is a section from UTAH's fishing regs. Notice section "d". unfortunately those of us in western states are restricted on what we can take. If you want to help change this click on the link in my sig. I provided a link to UTAH's fishing rgs as well...refer to pg 9 if you want to read the whole thing.
(1) A person possessing a valid Utah fishing or combination license may take crayfish
for personal, noncommercial purposes during the open fishing season set for the given body
of water.
(2) Crayfish may be taken by hand or with a trap, liftnet, handline, pole or seine,
provided that:
(a) game fish or their parts, or any substance unlawful for angling, is not used for bait;
(b) seines shall not exceed 10 feet in length or width;
(c) no more than five lines are used, and no more than one line may have hooks
attached (bait is tied to the line so that the crayfish grasps the bait with its claw); and
(d) live crayfish are not transported from the body of water where taken.
http://wildlife.utah.gov/guidebooks/2006_fishing/2006_fishing.pdf