There are few exceptions, but the taking of crayfish other than with hook and line is authorized when a stream is otherwise closed to fishing (CCR Title 14, Section 5.35(e)). Typically, crayfish may be taken only by hand, hook and line, dip net or with traps not over 3 feet in greatest dimension (CCR Title 14, Section 5.35). Most crayfish have no limit and the season is open all year. However, Shasta crayfish are protected and so there are specific river and lake closures listed for their protection in the 2014-15 California Freshwater Fishing Regulations booklet (see Page 21), as well as online at www.dfg.ca.gov/regulations. Look for subsection (d) of this section for the closed waters to avoid.
The limit is 35 and the minimum size is 4 inches measured by the shortest distance through the body, from edge of shell to edge of shell at the widest part, except there is no minimum size in Fish and Game Districts 8 and 9 (around Humboldt Bay). They may be brought to the surface of the water for measuring, but no undersize crabs may be placed in any type of receiver, kept on the person or retained in any person’s possession or under his direct control; all crabs must be measured immediately and any undersize crabs must be released immediately into the water (CCR Title 14, Section 29.85 (b)(c)).