California Code, Fish and Game Code - FGC § 9023

(a) Traps may be used throughout the year to take carp in any district under the restrictions set forth in subdivision (b).

(b) Traps shall not exceed six feet in greatest dimension.  They shall be made of cotton or nylon twine.  Meshes shall not be less than three and one-half inches in length, except that fyke and bait bags may be any size mesh.  Traps shall have only a single vertical fyke opening at the top of the trap.  They shall be baited only with grain or grain products.  Fish other than carp taken in traps subject to this section shall be immediately returned to the water.