Movie "47 Meters Down" Gets Sharks All Wrong

The new movie "47 Meters Down" is an affront to science and ocean biology. It stars Mandy Moore, so I will assume it is also an affront to acting in general. But I'll stick to the science, which is bad enough.

The basic premise: Two sisters go shark cage diving in Mexico. The cable breaks, and they are sent plummeting to the ocean floor, 47 meters down, and are trapped there with white sharks swimming all around. A tough situation, but I'd rather be there than in this theater watching this movie.

The whole movie hinges on a single decision: whether the girls should leave the cage and swim with the "dangerous" sharks up to the surface, or wait until the rescue team comes.

There are some basic scientific problems with this premise.

First, there isn't much time to make this decision. Both of the women have one oxygen tank. As soon as their predicament starts, they start breathing quickly and heavily. Based on the oxygen required to breathe at that depth and the limited amount in their tanks, this movie should last about 15 minutes.

"These characters are at 47 meters, which is around 155 feet, with a single scuba tank," Chris Lowe, a professor of marine biology at CSU Long Beach told Inverse. "The reality of it is that they are going to run out of air in 15 minutes, and because they're panicked, they are breathing harder and faster."

The women are advised to stay in the cage. This is idiotic. The idea that you would stay inside a cage trapped at the bottom of the ocean is about as dumb as paying for a movie that stars Mandy Moore.

As production goes, I get it. If the movie ended with the divers simply swimming to the top, it would be a pretty short movie and we would all be pissed that we didn't even finish our tub of popcorn before the movie ended. The producers needed to draw out the scenario and make this schlockfest last for over 90 minutes. I don't blame them for that.

What I do blame them for is the nonsense of instilling an unhealthy fear of sharks into the movie.

Sharks are not interested in eating divers. Sharks are predators of opportunity. They don't just attack you for the sake of attacking you. They are survivors. Divers, with their shiny tanks and bubbles and masks, do not look like easy prey to a shark. Sharks would not risk the chances that they might get hurt by attacking you, which is why most sharks avoid divers entirely.

"99.9 percent of the time that shark is going to check them out, think 'what the hell is that,' and then take off," said Lowe.

The idea that if you go swimming with great white sharks that they are going to eat you is a pop culture myth propagated to sell movie tickets. Sharks are not the aggressive violence-seeking predators that we make them out to be in movies.

The myth is especially upsetting because shark populations are declining worldwide. When the media and pop culture demonizes sharks, it makes it hard for conservationists to mobilize public sentiment to do anything to protect them. Sharks are a vital part of the ecosystem and important for maintaining the predator-prey relationship.

The divers are also advised not to return to the surface because they would get the bends. The bends, also known as decompression sickness, afflicts deep sea divers who stay at depths for an extended amount of time and then return to the surface too quickly. The rapidly changing pressure causes dissolved nitrogen in the blood to come out of solution and form bubbles in the body. Incredibly painful.

The movie gets this all wrong as well, according to Lowe.

"If they were dropped to the bottom, and let's just say they have a full tank when that happened, they would have about 15 minutes of air before they would run out, at best. They wouldn't be deep long enough to require what we call decompression stops, which allow that nitrogen to come out of your blood and for you to exhale it, so that you wouldn't get the bends."

So the divers are told to stay in the shark cage so that they don't get the bends they are almost certain not to get, and not to ascend to the surface to save themselves since the sharks will certainly eat them alive, which they won't. The divers heed this bad advice so the movie can drag on.

The American myth of the killer shark is here to stay. We love to fear them and movies and pop culture continually support this and demonize sharks in the process, making them harder and harder to save.

What is almost impossible to save is the premise of this movie. i understand that the writers and producers are not scientists. However, it takes just as much effort to get the science right as it does to get it wrong.

Someone tell that to climate change deniers.