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effects to the endangered fish and their critical habitats from mercury within the action area are <br /> described in the Effects of the Action above. We are not assuming an increase or decrease in <br /> mercury inputs or outputs to the action area, and thus, do not expect a worsening of the condition <br /> of the endangered fish or their critical habitats from mercury contamination. Instead we expect a <br /> continuation of the status quo—chronic, sub-lethal insults to the most sensitive individuals, <br /> which does not rise to the level of a large and detectable decrease in numbers,reproduction, or <br /> distribution. <br /> 4.5 Jeopardy discussion and Conclusion <br /> After reviewing the current status of the Colorado pikeminnow,razorback sucker,humpback <br /> chub, and bonytail, the environmental baseline for the action area,the effects of the proposed <br /> action, and the cumulative effects, it is the Service's biological opinion that the project, as <br /> described in this biological opinion, is not likely to jeopardize the continued existence of the four <br /> endangered fish. We have reached this conclusion based on the following reasons: <br /> • Of the four endangered fish, mercury concentrations in fish tissue have only been <br /> recorded in the Colorado pikeminnow,which is the species most likely to bioaccumulate <br /> mercury because it is at the top of the food chain and very long-lived. Mercury <br /> concentrations in many Colorado pikeminnow within the action area have been <br /> somewhat elevated in the past and indicate that the species is likely to be experiencing <br /> negative, sub-lethal impacts from mercury that are not insignificant. We do not have <br /> evidence,however, that mercury in the action area, in general, or the mercury released by <br /> project activities,in particular, is causing population level effects for any of the <br /> endangered fish species. <br /> • To the extent a degraded baseline condition exists for the endangered fish because of <br /> mercury contamination, we believe the proposed action does not contribute to the <br /> deepening of such degradation in a significant way. The baseline condition is not <br /> degraded by mercury to an extent that the likelihood of recovery would be reduced <br /> appreciably solely due to the additional amount of mercury that will result from the <br /> action. <br /> • Although fish tissue selenium concentrations have not been measured in all four of the <br /> endangered fish (Colorado pikeminnow only), the most recent fish tissue concentrations <br /> indicated a minimal risk to fish health. <br /> • None of the four endangered fish species are meeting recovery targets within the Green <br /> River subbasin,which includes the Yampa and White Rivers in the action area. <br /> However,we believe this is primarily a result of nonnative species that have increased in <br /> the action area and large-scale habitat alteration (e.g., dams and diversions). These <br /> impacts are not increased as a result of the proposed action. <br /> 59 <br />