Distribution patterns of fishes in the Lake Izunuma-Uchinuma basin in Miyagi Prefecture, Japan

Abstract

A fish survey was conducted in the influent rivers in Lake Izunuma-Uchinuma basin. Based on their distribution, fish species were categorized into three groups. Group-A was distributed in upper area of the rivers, and included six species such as Lethenteron reissneri and Pseudobagrus tokiensis. Group-B was distributed in the lower area of the rivers, and included largemouth bass Micropterus salmoides and Tridentiger brevispinis. Group-C was distributed in the wide length of the rivers, and included two species such as Rhinogobius sp. OR and Misgurnus anguillicaudatus. The number of fish species in the upper area of the river was higher than in the lower. Comparison of the results with a previous study conducted fifteen years earlier indicated populations of several fish species in the lower area of the rivers have decreased due to environmental degradation and largemouth bass.