Geographical distributions of the control region (CR) haplotypes. Geographical distributions of individuals with each CR haplotype (see Figure 2). Shading indicates the putative natural distribution area of each clade. Locality numbers given to sampling sites correspond to those in Additional file 1 and Figure 1. (a) R., river; L., lake; M., moat; Is., island; P., pond; W., waterway; D., dam; Re., artificial reservoir; F. M., fish market. (b) Water systems with artificial reservoir(s). (c) Analysis of the three mtDNA genes suggested that these three specimens appeared to have haplotypes belonging to clade IV. (d) Analysis of the three mtDNA genes suggested that one of the three specimens appeared to have a haplotype belonging to clade VII.