Corrected entry: Bruce The Shark could not possibly have known that sea mines explode. To him, they'd be globes of metal bobbing about. If one of the mines in that minefield had gone off - allowing Bruce to see what a mine does - they would all have exploded. The shock wave underwater would have detonated all the mines - it's called a sympathetic or adiabatic explosion. Even if Bruce survived the experience, the minefield and wrecked submarine wouldn't have.
JC Fernandez
3rd Apr 2008
Correction: How could he not possibly have known? It may be information that was imparted to him, much like he imparts it to the other characters. Or, considering it's estimated that Great Whites may live for 100 years or longer, he may have witnessed a mine explode at another in his life (like during WW2). Finally, under perfect conditions, one mine may detonate all the remaining mines, but perfect conditions don't always exist.
JC Fernandez