Been talked about a lot if you search this thread.
Yes, people have caught it. Most of us after LOADS of time walking on and off the beach.
If you haven't done so yet, buy the fishing upgrades from the bait shop. If they're locked, look around everywhere for "flopping fish". IIRC, there's one in the north jungle right near the cave exit, where the Macca plant regenerates, and there's another in the sewer tunnels somewhere. There may be more, I'm sure there's a guide somewhere in the thread. Once you find the flopping fish, you'll be able to buy the upgrades, which will make fishing easier.
The other thing that helps (I think) is the four-leaf clover. There are four clover leaves hidden around the jungle individually. Put them all together using the offering-prayer thingy and you get a lucky four-leaf clover. That'll bring you luck when fishing.
Other than that, just keep walking on and off the beach until you spot a shark, use the Heavy Pink Plug (as Evie suggested, some folks have had luck with other lures) and try for EVERY Great White, even if it looks small. You'll get there.
