Spatial distribution of a single river endemic allotetraploid spined loach, Cobitis takenoi, in comparison with a co-inhabiting tetraploid congener species

Cobitis takenoi (hereinafter, Tango loach), an endangered species of tetraploid spined loach, is known to inhabit only a limited area of the Noda River in Kyoto Prefecture, Japan; it coinhabits this area with the tetraploid congener Cobitis sp. BIWAE type A (hereinafter, Ohshima loach) without interbreeding. This study used field surveys to reveal the spatial distribution and habitat selectivity of Tango loach and its interspecific relationships with Ohshima loach during the non-breeding season. Tango loach seemed to prefer a muddy bottom and be more concentrated in specific areas than Ohshima loach.