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Evaluation of Potential Subsidence Impacts of Longwall Mining in the Spruce Stomp Lease Area <br />to Aquatic Life and Water Supply <br />genetic lineage. This analysis identified the West Fork Terror Creek and Cunningham Creek <br />cutthroat trout populations as GB- lineage cutthroat trout. <br />MEC, working under the direction of Bowie, conducted sampling at five locations along West <br />Fork Terror Creek in 2012. This effort produced density estimates of 563 +/- 35 fish /mile and <br />352 +/- 35 adult fish /mile at a lower West Fork Terror Creek sampling location and 1,319 +/- 47 <br />fish /mile and 600 +/- 14 adult fish /mile at an upper West Fork Terror Creek sampling location. <br />MEC also sampled fish at three locations not previously sampled by the USFS. These locations <br />had similarly high fish density measurements (see Appendix 3). <br />MEC also collected cutthroat trout fin clips for analysis of mtDNA sequence. Based on this <br />analysis, the cutthroat trout population in West Fork Terror Creek has approximately 94 percent <br />purity as GB- lineage cutthroat trout. <br />Concurrent with the preparation of this report, an article was published in the Journal of <br />Molecular Ecology that further examines the historic genetic diversity and ranges of cutthroat <br />trout populations in Colorado (Metcalf, 2012). This research identifies that the only existing <br />population of greenback cutthroat trout is located in the Arkansas River watershed. Further, the <br />fish previously assigned to the GB- lineage were found to share genetic signatures with historical <br />fish collections from the Colorado River basin. Based on this, GB- lineage cutthroat trout, <br />including the West Fork Terror Creek cutthroat trout population, are not members of the <br />greenback subspecies. The USFWS indicates that they plan to reassess the Agency's position <br />toward GB- lineage cutthroat trout populations in the Grand Mesa, Uncompahgre and Gunnison <br />National Forest. <br />Based on the best available information, it appears likely that the West Fork Terror Creek <br />cutthroat trout population is of the Colorado River variety. In 1999, the USFWS determined that <br />the Colorado River cutthroat trout did not warrant inclusion on the listing as an endangered or <br />threatened species. The Colorado River cutthroat trout is identified as a sensitive species <br />requiring special management designation by the USFS and BLM. Additionally, the Colorado <br />State Parks and Wildlife identify this subspecies as a species of special concern. As such, special <br />conservation requirements may apply to activities that may impact the fish. <br />121 - 014.000 Wright Water Engineers, Inc. Page 13 <br />January 2013 <br />