Sharks have the ability to see, but they cannot see colors. Dolphins, whales and other aquatic animals are also color-blind. Marine animals' survival is not dependant on the ability to see color, but rather the ability to see contrast in colors.
Rod cells are linked to the measurement of brightness, and cone cells distinguish colors. As of 2014, the retinas in 17 different species of sharks have been studied and rod cells were found in each shark. Of the 17 species of sharks, only seven displayed signs of one type of cone cell. So sharks are able to see in various light levels, but are most likely color-blind. There are over 400 species of sharks, making it impossible to determine if all sharks are color-blind.