Orcas have pretty good eyesight below and above water, and can often be seen spy hopping, where they raise their head vertically, apparently taking in their surroundings.
However, as they live in an often murky underwater environment, communication is more suited to acoustic methods than visual. So they take full advantage of the fact that sound travels further in water than air. They can communicate with members of their pod through a series of calls and whistles, that can be heard for many miles.
In addition, they’re able to “view” their environment through echolocation. Like a submarine using sonar, or an OB/GYN with a sonogram, they are able to send out pulses of sound that will send back information used to create a visual picture. This sophisticated technique is able to detect the difference between species of salmon, so they can expend their energy into catching the fattest and largest salmon, Chinook.