Sharks are a group of fish, most of them carnivorous, that can be found in all seas. They are classically seen as solitary hunters, searching the sea for food, though in reality this applies to just a few species.
Sharks also lurked around dive sites, providing ample obstruction for Edward. Since weaponry would slow him down while swimming, the Assassin had very few means of combatting the underwater predators, though he could stun them briefly if they got too close. Hiding inside wreckages or dense forests of kelp was an effective way of evading them.