(You do not need to jump this high) just 8 metres out of the water.
High jump is one of the Tiger Shark's missions. It requires to jump 8 metres out of the water. If you successfully completed, it rewards you with 600 coins.
How to find and complete[]
To complete, simply reach the surface and jump / boost with all your shark's might! It is harder to do if prey is not above you, because that can slow your boost down. If that doesn't work, jump on a Turbine which make the mission even simple.