What I wrote on sand crabs —
Sand Crabs. Three species of mole crabs are found in California and one, the gray sand crab, Emerita analoga serves as one of the best shoreline baits for surf fishermen and pier anglers trying out the surf area. They are the best bait for corbina and one of, if not the premier bait for the large barred, calico and redtail surfperch that inhabit the state’s beaches.
Unfortunately, live sands crabs, once wildly available and a mainstay of the live bait trade at bait shops, especially those in southern California, are no longer available. Today you’ll need to find your own sand crabs. The good news is that they are easily caught if the angler has one of the small sand crab screens aka rakes. Unfortunately, the screens, once also common at bait shops, are also harder to find. The good news is that you can order them on the Internet. Prices range from about $35 to $50 depending upon the size you need (look for sand crab rake or sand flea rake). With a rake you can often catch a full day’s bait in less than half an hour.
Where to look? Initially look for bird activity along the water’s edge. If you see birds in the surf area they are generally looking for food and often that is sand crabs. Next, walk along the water’s edge and watch as the water washes up and back down the sand. A telltale sign will be small V’s in the sand as the water recedes. These are tiny little sand crab antennae sticking out from the sand. These are typically seen when the crabs are near the top of the sand. A bubble or dimple in the wet sand near the water’s edge can also indicate where crabs are burrowing. Sometimes during the winter months the crabs will be a little deeper, and harder to find, but they’re still there.
If using the sand crab screen let the ocean do most of the work. Face the sea and while holding the screen above the water let it rush in. As soon as the water crests, kick up a little of the sand and drop the screen onto the sand and let water and sand flow through the screen toward the sea. Hopefully the water will contain some sand crabs.
If you do not have a screen you can use your hands or a small hand shovel. It’s a little harder and more time consuming but simply dig through the wet sand looking for the crabs.
When catching the crabs, you will sometimes find both the (molting) soft-shell crabs and hard-shell specimens. Longtime surf fishermen argue, sometimes vehemently, about which are best to use. Many anglers swear by the soft-shell variety and I think they do probably catch more fish as long as they aren’t too soft and soggy. Some swear by the hard-shell specimens and although they probably catch less fish, they feel they catch the bigger fish. Then there are those who suggest a medium-hard shelled crab, one whose shell has the hardness of a soft drink can.
Basically all three can catch fish and the question sometimes becomes one of time, how long do you want to spend collecting the bait? If you only want the soft-shell or hard-shell variety it can multiply the amount of time you are looking for the crabs.
All do tend to agree on size with most anglers preferring sand crabs about as long as a quarter give or take an quarter of an inch (button size to half dollar size). Whichever variety and size you have, the general way to hook them is up from the belly through the back with baitholder hooks or Kahle hooks. An easy way is to look for the two spots on their back and hook up through one of those spots.
You can keep the crabs in your bait cooler during the day. If some are left at the end of the day keep them in a dry plastic container overnight. Keep a damp newspaper or piece of kelp over them but do not have water or sand in the container.
If some die they can be frozen. A trick I learned from Bill Varney was to squeeze some taco sauce over the frozen crabs which seems to enhance their fish catching ability when the crabs are thawed. They can also be frozen with some meat and juice from mussels. This too seems to enhance their ability to attract fish.
The white sand crab, Lepidopa myops, and the spiny mole crab, Blepharipoda occidentalis, are both occasionally seen but are infrequently used as bait. The white sand crab is found in sheltered sand beaches at Newport Bay and points south while the larger spiny mole crab is found on sandy beaches as far north as Drakes Beach. One time I ran across one of these large spiny mole crabs while fishing on Crystal Pier in San Diego. Another angler gave me the crab along with a cup of smaller sand crabs when he was leaving the pier. He had caught the crabs but I'm not sure what he thought he would catch with the larger crab since it was over 3-inches in length.