Hungry Shark Evolution all sunken items are special collectibles that will complete the game progress. The more you collect, the more coins you will get. When you find one of the treasure, you will receive a random amount of either coins or gems depending on your luck. Then, on your next treasure finding, the amount of reward you get will increase. The reward will increase as you get more treasure so it is a good thing to pursue, considering that you are able to tackle most of the obstacles on the game such as preys, terrain, and things like toxic barrels and mines.
In Hungry Shark Evolution all sunken items, there are 15 items ready to be collected since the 3.9.2 version. As mentioned before, you can collect them to increase your resource. What makes the sunken items are hard to get is the location. Not every sunken item can be picked easily. Some of them require you to have a certain shark or meet a certain upgrade level. The majority of the treasures are located in a dangerous place that can be accessed by sharks such as Ice Shark, Megalodon, and the Great White Shark.
The treasures in Hungry Shark Evolution all sunken items are generally not related to the game such as electric guitar, dart board, jade dragon, or even a teddy bear. There are several treasures that you can get only in a specific map such as False teeth in the tunnel of death, Wakaba in the West Ocean, and Framed Picture of an Egg in the Kempy Cave. Other treasures are a clockwork robot, a moon on a stick, leaning sea tower, toy robot, ghetto blaster, bog brush, and Shark of the Covenant. To be able to get all of them, make sure that you have a capable shark and it is best to fully upgrade it.