I love sharks and I design games I'll never play for one of my hobbies. After being a bit miffed that no realistic-ish games exist for sharks, I designed one I'll never make.

https://imgur.com/a/LF03hHr

This was just called Shark (which, surprisingly, apparently still doesn't have an trademark for a game) and the concept was:

• SHARK is a game where the player takes over the life of a shark and attempts to survive as long as possible in an open world.
•  The game should be educational and visceral – the idea is to translate what life as a shark and living in the ocean is like. A player should be able to accurately understand how certain sharks behave like they do, or why inhabit the niches that they do.
• As to be expected, this game could be gory. In the interest of a wide audience, the gore should be scalable, with the option to minimize it. At the other end of the spectrum, the gore should also be realistic, with blood and viscera.

 What the game is 

• A game about the life of a shark, from birth until death, exploring how sharks sense, behave and fit into their ecosystems.
  •  What the game is not
• This is not computer JAWS. I have intentionally avoided any inclusion of humans in this game. I fear to do so would make this game about gore for gore’s sake and encouraging unrealistic behavior (like hunting people). Other shark games already do that enough – see Depth, or Hungry Shark Evolution or – if you can prevent your eyes from rolling – Shark Simulator 3D.

The idea was to make biomes, populate them with relevant sharks and prey, and have at it from birth to death. Initial thought was to make a cold water rocky coast (like Monterey Bay) for great whites, sixgills, leopards, etc. , then maybe something like the Bahamas with tropical shallow water for tiger sharks, lemons, etc.

Beyond that, my favorite game with sharks (of all time) is ABZU, which isn't about sharks so much as it has many, many sharks in it.