Clams and Oysters
March 30, 2017
I (Steve) had never really given clams and oysters too much thought. Clams came in chowder, and oysters on a shell, perhaps. Or I thought maybe clams were freshwater and oysters were saltwater. Well, here we are in Cedar Key, Florida, and it turns out to be a really good place to learn about them. We toured the Southern Cross Sea Farms, one of many aquaculture farms here in Cedar Key to learn more.
But first, some history. Cedar Key's story is one of boom and bust over the years. It was a busy rail depot/seaport for cargo to New Orleans and passengers to Key West or Havana, until Tampa came online and took over. At one time there were two pencil factories in town, until the red cedar ran out. The fiber factory supplied the brush industry all over the world from 1910 until 1952, when synthetic fibers took over. And the fishing industry carried the town until net fishing was banned in 1995. Then the State of Florida and the University of Florida introduced aquaculture to the area.
Back to clams and oysters. You can read all about the differences here. But here's the simple version: Both are saltwater bivalves. Clams have a smooth shell, and oysters have a rough shell. Clams like to be in the mud, while oysters like to be up out of the muck, preferably attached to a rock. Clams move around during their life, while oysters like to stay in one place. Both are delicious.
Most of what Southern Cross raises are clams. They start out by spawning. While clams in the wild only spawn during certain seasons, in aquaculture farmers can manipulate the changes in the water temperature so that the clams think it's spawning season all year long. :-) They identify the males and females based on the fluids coming out of them. So they separate the girls from the boys and collect the eggs and the sperm. Then they mix sperm and eggs in the right proportions and create millions of tiny little clams.
After 24 hours, the baby clams are visible under a microscope. We saw them under a scope swimming around. Then they go into tanks where they get to feed on a diet of algae. Basically at this point they just look like colored water.
Over the next year or so, the clams keep growing, first in indoor tanks, then outside in larger tanks. Workers use screens to separate larger clams from smaller ones and keep the tanks filled with similar-sized clams. Water from the bay is pumped through the tanks, giving the clams the nutrients they need to grow.
After a few months, the clams are the size of small pebbles. Here's a tray with 40,000 to 50,000 clams.
The clams spend about a year out in the gulf. During that time, they get visited by the aqua-farmers, who separate the larger clams from the smaller ones and put them into different bags. As it turns out, one clam will climb on the back of another to get a better shot at the food coming by in the water. But eventually they all get their chance to grow to full size. Once the clams are full size, the bags they are in are collected off the ocean floor for the last time, and the clams come ashore for sorting.
Here they go through an initial sorting, where whole clams are separated from empty half shells.
One guy feeds them into a rolling drum with lots of water. Most of the empty half shells fall out, and whole clams come out the end. But there's still a lot of hand work in separating whole clams from shells. These guys do this all day long.
The aquaculture farms here are wildly successful. At this time, 95% of the farm-raised clams in the US come from little Cedar Key. And, of course, you can get some of the best fresh clams at pretty much any restaurant here.
Want to learn more? Here's a link to the Southern Cross Sea Farms site. And here's a video that Southern Living did about the clamming industry in Cedar Key. Next time you enjoy a nice clam chowder, you'll remember that these clams probably grew up here in Cedar Key.
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