What's the difference between dockage and wharfage?

Dockage

Definition:

• (n.) A charge for the use of a dock.

Example Sentences:

• (1) Dockage level varied among bulks of the same type of grain, but the mean dockage in any one crop was always larger when originating from the USA than from other countries.

Wharfage

Definition:

• (n.) The fee or duty paid for the privilege of using a wharf for loading or unloading goods; pierage, collectively; quayage.
• (n.) A wharf or wharfs, collectively; wharfing.

Example Sentences: