We've experienced a revolution in the last 50 years in America.

Not over politics or religion or taxes – but a Blue Food Revolution: the growth of aquaculture (aka fish farming).

Step 1 of the revolution: Move out of the wild.

According to Paul Greenberg, author of American Catch: The Fight for Our Local Seafood, today about 50 percent of our fish are now raised on farms, as opposed to in the wild. With a lot of fears about factory-farmed animals swarming around, Greenberg is quick to add that farm-raised fish have an important distinction from their land-based friends: "The vast majority of the fish that we're eating has not been selectively bred. There's not a lot of genetic difference between the wild animal and the farmed animal." (Salmon and tilapia are notable exceptions to this rule.)

Step 2: Get your fish from foreign shores.

Americans love shrimp: It's the most consumed seafood in the country. But around 90 percent of that shrimp actually comes from Southeast Asia and other foreign markets – places where aquaculture is booming. And where rules for fish farming aren't nearly as stringent.

Step 3: Send fish from home on a long journey.

In an attempt to make our food more affordable, fish production undergoes a seemingly inefficient process. Part of the fish that we eat in America was actually caught on our shores. But to save labor costs, companies freeze fish and send them via boat to processing plants in Asia, where they are defrosted, boned, processed and refrozen.

"Squid, for example, will have often made a 12,000 mile round trip. You can be sitting in Santa Barbara, having some nice fried calamari, next to the boat that caught it – but meanwhile, in between it coming from the boat to your plate, it's made a bypass over to Qingdao and come back," he explains.

Paying a professional squid cutter in California could be 15-20 dollars an hour, whereas in China the cost is a fraction of that. Having done the math, Greenberg estimates that using cheaper labor, even while sending fish halfway around the world, saves the American consumer about a dollar a pound. The question he poses: Is it worth an extra buck for Americans to know that their fish were caught, cleaned and prepared a little closer to home?

A few other facts from our chat with Greenberg:

• Clarence Birdseye played a huge role in getting massive amounts of fish onto American plates. He invented the belt freezer, allowing fish to be frozen quickly enough to prevent ice crystals from forming in the filets.

• Branzini – that fish you think is fancy and Italian – is almost universally farmed today. The surge in its popularity happened thanks to the formation of the European Union. A speculative branzini market started in Greece during the early days of the EU, thanks to subsidies for fisheries.

• Dinners at conferences and hotels would be much more sustainable if we ate mussels instead of big, juicy filets of tuna and salmon.

• Farming bluefin tuna would be an energy intensive process: It could take up to 18 or 20 pounds of fish feed to create one pound of the final product.