In regards to the sharks, I know how to avoid being killed by them based upon the second photo:
When they are coming after you do not try to swim away- like you even could. Instead, turn and swim right towards them. Then, when the open their mouth to bite your in half, swim right in like really super fast and then swim right through that wide open gill. Shark would be completely confused and then probably just swim away.
dobber 1: shark 0