There are sharks in Britechester's waters?!

My sims were swimming down by Foxbury, when all of a sudden one of them starts calling out frantically. I pan over to see a fin in the water swimming past her, and the "Fin Fear" scared moodlet pop up.

Why are there sharks in university waters?

I know shark attacks are a type of death (and that it can kill vampires), but I'll be honest in saying I don't know much about the death itself. Do they kill in any type of water, or only deep, Sulani-based water?