California Code, Fish and Game Code - FGC § 7702.1

No sardines, anchovies, mackerel, or squid intended for or used in any cannery shall be unloaded from any vessel except at a weighing or measuring device approved by the Bureau of Weights and Measures.  Such products shall be weighed by a public weighmaster licensed as an individual under the laws of this state and a receipt as to such weight shall be immediately issued by the weighmaster to the fisherman at the time of receipt of such products.  Copies of such receipt shall be handled in the manner provided in Sections 8043 to 8047, inclusive.