The Twilight Zone | The Twilight Zone (1959 TV series) | Negative Zone | Panama Canal Zone | Eastern Time Zone | Twilight Zone | Korean Demilitarized Zone | The Dead Zone (TV series) | The Dead Zone | Pacific Time Zone | Hardiness zone | Central Time Zone (North America) | Ponce Historic Zone | Metekel Zone | Arsi Zone | The Twilight Zone (2002 TV series) | O-Zone | Mirab Welega Zone | Hadiya Zone | Gamo Gofa Zone | Debub Omo Zone | Zone | Semien Omo Zone | The Ultra Zone | Rapti Zone | Karnali Zone | Debub Wollo Zone | Dawro Zone | Central Time Zone | Agew Awi Zone |
Samples of bottom fauna taken in 1998 documented the presence of nationally rare species of gastropods such as Hippeutis complanatus and bivalve Swan mussel; and during the preceding decades two species of limnetic gastropods were documented.