A few weeks ago, after misreading the hours on the website, the Hacker and I found ourselves at an aquarium less than an hour before closing time. The woman behind the counter felt bad for us and let us in for half price, but I felt bad taking money from a nonprofit even if we didn’t get a chance to see everything, so I decided to check out the gift shop on our way out to see if I could make up for it a little.

If I hadn’t felt guilty, I probably wouldn’t have picked up Cod, but when I saw that it was by Mark Kurlansky, the writer who had miraculously made Salt interesting, I was intrigued. Since a book (even a potentially boring one) felt more practical than a stuffed shark, I decided to buy it.

Fortunately for me, it was not boring, which was unfortunate for the Hacker who was forced to listen to a steady stream of cod factoids for the next three days.

Cod fed the Age of Exploration…

Because cod is almost entirely protein, dried salt cod has 1/5th the weight of fresh cod and can keep for as long as ten years as a “durable woodlike plank.” In the days before freezers, cod’s keeping qualities enabled ships to head out into the unknown without worrying about resupplying. Every major European exploratory voyage from the Vikings to John Cabot used salt cod as its primary food source.

And it fed Caribbean sugar plantations.

In the 17th century, slaves working Caribbean sugar plantations needed food rich in salt and protein in order to survive the grueling work. Plantation owners didn’t want to waste any land on growing food for the workers, so they imported salted beef from England. That is, until the New England colonies saw an opportunity to offload badly cured salt cod that would have otherwise been discarded on a low-end market. Preparing cod for the Caribbean became so profitable that salt cod producers in New England struggled to produce high quality fish when slavery was abolished.

Catching a cod is easy…

Aside from cod’s exceptional durability, one of the main reasons cod was so popular was that it was easy to catch even in the days of line fishing when fishermen were only allowed one hook per line. Once a cod was on the line, and the hook was firmly set in its mouth, a cod didn’t struggle like swordfish do. All a fisherman had to do was pull up the line. That is until trawlers that ran nets along the ocean floor were invented, exploiting the cod’s natural tendency to go to the bottom when it is a afraid.

But being a cod fisherman is exceptionally hard.

Fishermen have traditionally operated on very little sleep, so the rate of accidents is extremely high. Any accident is compounded by the fact that cod is fished out of water that is between 34 and 50 degrees, and until recently the only thing to protect fishermen from freezing wet hands were rubber gloves lined with cotton. Since fishermen who have lost too many fingers from frost bite or accidents with machinery are forced into retirement, few fishermen are able to work past fifty.

Cod fishing inspired American capitalism.

In the early days of the United States, the cod was so revered that a life-sized wooden codfish was displayed in the Old State House in Massachusetts that was so revered that it inspired a standing ovation when it was moved to the new legislature. Silly as all that was, New England owed its existence to the cod, which provided early settlers a steady livelihood and familiar food when they were at risk of starving.

Later, on the eve of the American Revolution, when Massachusetts radicals thought of freedom, they thought of the cod industry where “men of no particular skill, with very little capital, had made fortunes.” To this day, American capitalism assumes that if you’re willing to work long hours, go without sleep, and put up with unpleasant working conditions like a cod fisherman, supporting a middle class lifestyle requires no particular luck or skill.