From the reg book:
"Resident Annual Shellfish License $7.00--Same qualifications as Resident Annual Angling License (see page 3 under Licenses, Tags and Permits)."
Does that apply, to crawdads? Not sure.
More info:
"Live crayfish may not be used as bait; and live crayfish taken for bait may not be released into Oregon water--except in the water body in which they were taken."
Hope some of that, is helpful.