estuarine zone
For purposes of this section, the terms “estuary” and “estuarine zone” have the meanings such terms have in section 1254(n)(4) of this title , except that the term “estuarine zone” shall also include associated aquatic ecosystems and those portions of tributaries draining into the estuary up to the historic height of migration of anadromous fish or the historic head of tidal influence, whichever is higher.