If you're talking about a "pier" ... as in a stationary walkway ...
I'd work the pier as though it were a dock. It offers shade (ambush) and cooler water temps (comfort) ... which are prime factors to fish. It may also have algae growth, which is sometimes eaten by baitfish species, so it may also offer a food source ... another prime factor.
The depth of the water below the pier will dictate whether or not the fish will be there ... and when they're likely to be there. Any cover that has been placed there, or washed in & lodged there, will be a spot to give greater consideration than the "empty" areas around/under the pier.
... cp
