Yes, you can use them in SoCal; you can not use the throw nets used in SF Bay.
From PFIC, 2nd Ed. —Drop Nets(also called Umbrella Drop Nets). Live bait, especially live anchovies, are by far the best bait for several species off of southern California piers. At the same time, fewer and fewer piers are offering live bait. In response, an increasing number of anglers are purchasing drop nets and catching their own bait. These nets are sold at many tackle shops, are easy to use, and usually will produce bait. The nets, 3 1/2 feet square, are attached to a rope and lowered into the water. Usually a few pieces of bread are sprinkled just above the net which attracts anchovies or smelt and the small fish are then pulled up to the pier via the net.