"The warmth of the water and the visibility is incredible, so you can see the whole ship from the surface, " says Easterbrook.

CNN: A worthy wreck for divers: USS Kittiwake

Even when the sharks are found closer to the ocean surface, they spend their time in the cool-temperature, plankton-rich waters that limit underwater visibility and make diving difficult.

CNN: Scientists discover winter home of world's second-biggest fish