Laserfiche WebLink
the few Colorado pikeminnow that were tested in the 1980s showed that their selenium fish <br /> tissue levels indicated a minimal hazard. We do not know where current selenium fish tissue <br /> levels stand in Colorado pikeminnow in the Yampa or White Rivers, but given that water <br /> concentrations in these two rivers are generally below the chronic standard, we have no recent <br /> data indicating that there is immediate cause for alarm. This contrasts with the water selenium <br /> concentrations that have been measured within Colorado pikeminnow critical habitat along the <br /> Gunnison River, for example,where surface waters have often exceeded Colorado Water Quality <br /> Standards for selenium (CDPHE 2011). <br /> As stated above,we believe nonnative species are the primary limiting factor for Colorado <br /> pikeminnow numbers, successful recruitment, and their distribution within the action area. <br /> While we do believe that further sampling and testing for selenium is warranted, we do not see <br /> any evidence indicating that potential effects from selenium rise to the level of reducing <br /> population numbers, are limiting reproduction, or are constraining Colorado pikeminnow <br /> distribution. <br /> 4.3.2.2 Razorback sucker <br /> We have no data on past or current selenium fish tissue levels in razorback sucker in the Yampa <br /> or White Rivers. However,water selenium concentrations in these two rivers are generally <br /> below the chronic standard; we have no indication that there is immediate cause for alarm. This <br /> contrasts with the water selenium concentrations that have been measured within razorback <br /> sucker critical habitat along the Gunnison River, for example,where surface waters have often <br /> exceeded Colorado Water Quality Standards for selenium (CDPHE 2011). <br /> As stated above,we believe nonnative species are the primary limiting factor for razorback <br /> sucker numbers, successful recruitment, and their distribution within the action area. While <br /> further sampling and testing for selenium is warranted, we do not see any evidence indicating <br /> that potential effects from selenium rise to the level of reducing population numbers, are limiting <br /> reproduction, or are constraining razorback sucker distribution. <br /> 4.3.2.3 Humpback chub <br /> We have no data on past or current selenium fish tissue levels in humpback chub in the Yampa <br /> or White Rivers. However,water selenium concentrations in these two rivers are generally <br /> below the chronic standard. Very few humpback chub currently occupy the Yampa River and <br /> we have no data indicating that they occur in the White River. We have no data indicating that <br /> there is immediate cause for alarm, although further sampling and testing for selenium is <br /> warranted. <br /> As stated above,we believe nonnative species are the primary limiting factor for humpback chub <br /> numbers, successful recruitment, and their distribution within the action area. While further <br /> sampling and testing for selenium is warranted,we do not see any evidence indicating that <br /> potential effects from selenium rise to the level of reducing population numbers, are limiting <br /> reproduction, or are constraining humpback chub distribution. <br /> 55 <br />