Using Shore Crabs as Bait
Small shore crabs, the kind you often see around pilings, rocks and jetties, make excellent bait for perch, cabezon, rockfish and several other fish. You will need to catch them yourself, but if you are in a good area, it won’t take you long to catch enough to go fishing (especially if you go out at night with a flashlight). To the north, you will find the gray to muddy-yellow, Hemigrapsus oregonensis. They will be found along mud banks, estuaries and under rocks. In southern California, more common is the greenish-purple colored crab, Pachygrapsus crassipes. They are very common around jetty rocks (just above the water line), mussel beds and tide pools. Sometimes you can also head under the shore end of a pier and find the crabs on exposed pilings. When you see reference to sidewinder crabs as baits, it will be one of these species or a similar type.
The one thing you need to do is be to be fast. They can seemingly detect the slightest movement and will quickly hasten to reach a safe hiding spot. When you spot a sidewinder approach it slowly, plan your grab and snatch, and do it fast. You might be able to grab it between two fingers while sometimes you may want to use a whole hand or a net. As soon as caught place it is a container, preferably one with a lid. Do be careful if on a slippery jetty rock! Live sidewinders can be kept for about a week if kept in a cool plastic container under wet paper or kelp.
To fish with these small crabs, and thumbnail-size specimens are the very best, grab them by their back and hook them through the last leg socket exiting thorough the opposite leg socket.
Fish them right around the pilings, a few feet under the surface of the water. If possible, and it requires a pier built close to the water, you can try to float a small crab into a school of pileperch (which are generally right up next to pilings). Usually it requires a light, 4-6 pound test line, and a small, size 8-10 hook, but the results can make the effort worthwhile. Large rubberlip perch also find these crabs to be tasty morsels and many times crabs are almost the only bait which will catch these two larger species of perch, a condition I have seen in San Diego Bay, San Francisco Bay, Bodega Bay and Humboldt Bay. To the north, the crabs also make excellent bait for cabezon and rockfish. In fact, almost 100% of the cabezon I have caught off of piers in northern California have had crabs in their stomachs.