The movie starts off with a sea captain and his crew catching sharks and slicing off their fins to sell for soup. As they set the scene, they discuss the major moneymaking opportunity to be had, as there was a record-breaking pod of 20,000 great whites all congregated in the sea.
All right, let's digest that. What would it take to get 20,000 sharks to come together? This is a tough one. The movie highlights great white sharks, but do that many great white sharks exist, and are they located even remotely near each other? It's impossible to put a number on the population of these guys, but the great white was not doing so well for many years. Off the coast of California in the 1970s and 1980s, there were estimates of only 219 of these sea creatures in existence. Thanks to legislative action to protect the sharks, estimates from a 2011 census put the number at closer to 2,400 adult great whites [source: Lee]. Still not 20,000, but 2,400 will do to get us a legitimate sharknado with a few hundred sharks in it.
We've figured out the number situation, but we still have to get a bunch of sharks into one spot. For the most part, sharks are loners; they don't travel in packs. That said, studies have shown that some sharks will form groups to hunt (cooperative hunting), and that aggregating also may help with migration [source: Viegas]. So to make this sharknado work, we're going to have to select a place and a time of year that match up with their migration patterns.
Thankfully (for creating a sharknado), great white sharks tend to spend most of their lives relatively close to shore [source: Schwartz]. Ideally, we would find a way to remove most of their food options for a bit to increase their appetite and then plop into the water a big, bloody mess of food to get them to congregate. Generally sharks can detect pressure changes associated with oncoming storms, and they take evasive action, going into deeper waters [source: Gray]. So we'll have to make that mess of food really enticing to fight against this tendency.
We've painted the picture of what needs to happen to the sharks to get them primed to be sucked up into a sharknado. Let's take a closer look at the weather system needed to take these sea predators into the air.