Distributional Changes of the Fishes of the Hatchie River System in Western Tennessee and Northern Mississippi

Abstract

Ichthyofaunal surveys of many river systems in the southeastern USA have been completed. However, subsequent surveys of these systems have been limited to searches for species of special interest and studies of anthropogenic effects on portions of river systems. Thus, little is known about temporal variation at the system level. The Hatchie River System (HRS) in northern Mississippi and western Tennessee was intensively surveyed in 1972 and again in 2001–2003. Data from 272 collections (130 localities) were used to determine patterns of species distribution and any changes that may have occurred in the past 30 years. Dispersal from neighboring systems, introductions, ecological effects, and sampling techniques appear to have influenced the distribution and composition of the known HRS species. Of the 107 known HRS species, 15 were collected for the first time since 1975, six were only collected before 1975, and 40 changed in the collection frequency between sampling prior to 1975 and in 1975 to the present. An intensive, system-wide survey was necessary to detect the changes in distribution and increase in the number of known species from the HRS.