See our 4-minute California Matters segment on oysters and ocean acidification here.

At 3:30 in the morning, a long pink building at the dead end of 22nd Street on the San Pedro waterfront is abuzz with activity while the rest of the city is asleep. Cars start pulling up to the docks, people haul coolers up the ladders and fishmongers weigh, scale, gut, and fillet a variety of tuna, salmon, snapper, halibut, albacore, and more.

But this isn't just business as usual on a Saturday morning. From around 3:30 to 7:30, on this one day only, the wholesale fish markets along Signal Place open their doors to the public. If you're one of the early risers, you can find whole tuna and salmon for as little as $3 per pound, or sardines and mackerel for as little as $1 per pound. You'll see water tanks full of live crab and bins of ice filled with shrimp of all sizes. Squid, scallops, clams, oysters, lobsters, even baby octopi -- they're all here. Don't wear your nice shoes or your nice clothes; the floors are constantly wet and while the markets do provide disposable gloves, this is the type of place where you really have to dig your hands in.

There are four or five bays that operate every Saturday, and their seafood is the freshest you'll find in L.A. -- after all, they're coming straight from the docks. It's worth it to walk through all the bays before you buy and do some comparison shopping. Get there early, as your choices start dwindling by the time the sun comes up and the markets close to the public by 8. If you're not one of the veteran shoppers that brought their own coolers for the haul home, you can buy a foam cooler from any of the markets; crushed ice is complimentary.

And don't forget to hit up an ATM on your way to the fish markets; they are cash only.

San Pedro Wholesale Fish Markets, located along the docks on Signal Place and 22nd Street

Open to the public every Saturday, 3:30 to 7:30 am