As any rugged, bearded fisherman with a hook for a hand will tell you, sharks love death metal music. OK, it might not come straight from the mouth of a weathered seafarer, but this information does come straight from the mouths of the Discovery Channel and popular science site, I Fucking Love Science.
Turns out you can use that Iron Maiden to attract sharks. But that's a pretty dumb thing to do, since, well, they're sharks. However, if extenuating circumstances required you to catch a shark, quick base drum kicks and angry vocals would do the trick, as sharks are able to detect vibrations caused by sound waves through a sense organ that runs through their body from head to fin.
Thus, those same intense vibrations that attract your attention when your upstairs neighbor blasts Slayer attract sharks as well, but like, on a much crazier scale. Imagine if the wall rumblings ran through your entire body. You really wouldn't be able to sleep. And if you were a shark, well, you probably wouldn't sleep anyway. But that's a different story.