The Sun, a newspaper renown for its veracity, has an article (with pics!), with a sidebar by James Orr of useful tips on avoiding shark attack.
Here be a couple of them:
"NEVER urinate in your wetsuit or the ocean — sharks can detect it from five miles away and will think you’re a fish in distress, a ready-made meal."Go read the article:
"DON’T clap your hands and bark like a seal. Great Whites often attack humans after mistaking them for their favourite meal."
And remember, don't bark like a seal, kids...