Escaping the shark
The balloons popped, the faster you will travel and the better the chances of escaping the shark. Try to pop three or more balloons in a row when above the water in order to increase your speed. If you hit a fish or another obstacle, your speed will disappear and the shark will chase you again.
Gaining distance
You are safest while in air; try to remain airborne for as long as possible. Jump on bubbles above the water, then go even higher in space into a bubble and avoid asteroids. Jump out of the water early and pop the early balloons. You can go into space quickly and travel as far away as possible. Tap and hold while in the air to descend faster in order to land on other bubbles, which in turn will help you go higher.