First you must collect the 8 Mission Shells scattered around the map to unlock each of the 8 Basic Missions. After completing the first 8 missions, you unlock the Super Mission. If you die then any incomplete mission progress will be reset, so you have to finish any given mission within one life. All completed missions and shells found will remain though.
Mako Shark Missions:
2-1 Eat 3 Fishermen
2-2 Swim 200M Without Eating
2-3 Eat 5 Flying Pelicans
2-4 Eat 5 Enemy Sharks
2-5 Survive For 6 Minutes
2-6 Eat 3 Sailfish
2-7 Clear 5 Mines
2-8 Find 1 Sunken Object
2-9 Score Over 50,000 Points
Mission & Treasure Map 2:
For more game tips, see:
http://www.urgametips.com/2013/04/hungry-shark-evolution-faq... and my solution for Super Mission 1: