| The local populations of white spotted charr are one of the endangered fish spices in Japan. They have been affected the genetic contaminations with introduced populations. Sometimes their habitat divided by sediment control dams. Although obstructions of fish’s migrations by these artificial structures are unfavorable to conserve populations, the upper area will be refuge buffer zone against the terminator. And some valuable local populations of native white spotted charr are found remaining upper side of dams.The charr population on Tone river have been contaminated genetically with released fishes by fishery for over one half century. And it was supposed that some native populations have been remained on the upper streams around the Yunishigawa dam. And it is apprehensive that the dam construction menaces these populations with genetically contamination, because the part of their habitat will be under reservoir trough flood control. For the conservation of valuable population of the native white spotted charr that inhabit around the dam, the preservation area was selected basing on their genetic information of them. Fin samples from 192 charr were collected from the Tone river and two adjoining mountain streams. Samples were preserved in 95% ethyl alcohol until DNA extraction using a phenol-chloroform extraction protocol after proteolysis by Proteinase K (Qiagen, Germany). The sequence comparisons in the cyt-b on mtDNA (557bp) among all individuals and GEDIMAP (http://gedimap.zool.kyoto-u.ac.jp) judge the genotype. To estimate genetic hybridization career of the populations, Nine microsatellite markers and AFLP? method were applied and the genetic diversity and population genetic structure was estimated using AFLP SURV (Version 1.0; Vekemans et al. 2002). The genetic contaminations were confirmed on both two mountain streams by these analyses. The body length of the contaminated individuals shows that the introduced charr affects genetically to multiple generations. Only few populations found low contamination levels than other sites. Also the frequencies of introduced genotype are less in the upper mountain streams than lower area. Four local populations are selected to conservator by contributions these result. The individuals in the upper area were transplanted to the most upper area. |
