There are also ways to boost the Jump Power you gain. First is the common method of some Magikarp you catch having that as their individual ability bonus. This will allow for higher Jump Power from food, events or training. It differs between all Magikarp so be sure to keep a look out. Some Magikarp can even have this boosted by over 200% so it's worth checking.
There's also a general boost you get from Mayor Karp. Every time you have a Magikarp retire from being maximum level, Mayor Karp will give a 10% boost. In addition to that, every time you complete one of the four Objectives to beat the leagues, you will get an additional boost of 30% each. This is capped at a 600% boost in Version 1.0 and 950% in Version 1.1 so you cannot get any higher than that.