Oceanic White Tip question

It may be weird, but I have noticed that many Oceanics (like the ones frequently met in Elphinstone) have small holes on the upper side of their bodies- they look like bullet holes.

Any ideas what can it be? Is it possible that someone shoots at them with a rifle while they swim? (fishermen? bored soldiers?).. Just from curiosity

I don't think so. Post some pics if you have.

I don't have my own pictures- but I spent lots and lots of hours very close to observe the holes, so I asked from friends if they've noticed it too.

Here is an example- the shark has 6-7 holes on its upper side:
Oceanic white-tip shark photo - Frank Berger photos at pbase.com

It is difficult to take photos of the holes- they look with very round edges, something like 5-10mm diameter (wasn't close enough to measure with a caliber ) but to me it looks like buller holes. Could be just my imagination after seeing to many Hollywood movies..

I have seen such holes in 8-10 different sharks, all of them Oceanic White Tips which tend to swim slowly near the surface, making them an easy target for shooting?