The (semi --RRB- permanent damage taken differs with each difficulty level, so on the lowest one, the Way of the Acolyte, you'll start most encounters with almost full health, while you have to face much less and weaker enemies than on the higher difficulties. (hardcoregaming101.net)
The sharks are also visual predators, and will sometimes «taste» surfboards and kayaks if they suspect they're pinnipeds, which is the cause of most encounters. (parksconservancy.org)
In the game's defense it does try to break up the sense of monotony that comes with most encounters by utilising a couple of enemy types. (wolfsgamingblog.com)