California Code, Fish and Game Code - FGC § 8182

The operator of a boat engaged in taking anchovies in waters south of the line described in Section 8180 shall at all times while operating the boat identify it by displaying on an exposed part of the superstructure, amidships on each side and on top of the house visible from the air, the department registration number of the boat, in 14-inch black numerals on white background.