A Mako shark, weighing around 1,300 lbs. and measuring 12 feet was caught and killed because some guy thought that it was cool, but not cool enough to leave alive and forgo setting a record.
The man who caught it characterized it as a "killing machine," but unless LL Cool J and Thomas Jane actually didn't blow up the mutant super-smart shark from Deep Blue Sea, and the entire ending was some kind of huge cover-up, I'm guessing that this was just a regular (albeit big and probably very old) Mako. The shark's body is supposed to be donated to a research center, so perhaps more good can come of this than some guy having a possible record.
For funsies, here's an infographic on sharks vs. humans (too large to embed):