Spotted bay bass (spotted sand bass) are the most commonly caught and most heavily populated fish in both San Diego Bay and Mission Bay. They are aggressive, hearty, ever-present, and willing to feed almost around the clock, making them one of the easiest fish to catch in all of San Diego.
If you only have a few minutes to fish, and are anywhere close to either bay, you can probably go catch a spotted bay bass or two before anyone notices you're gone. Spotted bay bass can be found in all parts of either bay, but key in on the eel grass and marina structures in Mission Bay, and the harbors, clam beds, eel grass, and rocky shorelines of San Diego Bay.
They are most active when tides are moving, and typically an incoming tide is preferred by most anglers. For their size they're tremendous fighters, akin to a smallmouth bass in freshwater. Pound for pound, they're tough as can be.
Most anglers target spotted bay bass using artificial baits; 3-5" swimbaits and grubs, jerkbaits, crankbaits, and even plastic worms designed for freshwater bass. Berkley Gulp! products are a favorite, especially the swimming mullet. White, or light colors are generally most popular, but color is sometimes of little importance when fishing for spotted bay bass.
Typical freshwater bass tackle is perfect for fishing spotted bass. 6-10 pound line matched to the surroundings you're fishing is ideal.
Most spotted bay bass you'll encounter will be 1 pound or less, but females can grow to well over 4 pounds when laden with eggs in the spring. Mission Bay tends to have a slightly better average sized fish compared to San Diego Bay, but there are far more in San Diego Bay. Any spotted bay bass over 2 pounds is a good one, and anything over 3 is tremendous. But even the small ones are a joy to catch.
For more information, check out this great article on fishing for spotted bay bass in San Diego Bay.