Biological Opinions - Bureau of Reclamation

8.2.1 Comparison of the Effects of the Proposed Action to the Species Conservation
Needs
The following analysis relies on the findings presented in the Status of the Species analysis above
for the LRS and the SNS, especially with respect to their conservation needs, to express the
significance of anticipated effects of the proposed Project on these species.
8.3 Effects of the Proposed Action to the UKL Recovery Units of LRS and SNS
As discussed above in section 7, Status of the Species, the Revised Recovery Plan for the LRS
and the SNS (USFWS 2013) identifies two recovery units for both species: (1) the UKL recovery
unit; and (2) the Lost River sub-basin recovery unit. This analysis also relies on the survival and
recovery function assigned to each of these units to express the significance of anticipated effects
of the proposed Project on these species
8.3.1 Effects of the Proposed Action to LRS and SNS Populations in UKL
As described in section 7, Status of the Species, of this BiOp, UKL supports a population of the
SNS, and the largest population of the LRS. The proposed action is likely to affect habitat
availability for all LRS and SNS life-history stages, including embryos, pre- and post-swim-up
larvae, age-0 juveniles, older juveniles, and adults. Each sucker life stage has specific habitat
needs and specific seasonal time periods when those habitats are used. This analysis evaluates
the effects that the proposed management of UKL surface elevations and the resultant water
depths are likely to have on the quality and quantity of habitat for each LRS and SNS life-history
stage in UKL.
8.3.1.1 Effects to Shoreline Spawning Habitat
LRSs (and a few SNSs) spawn at shoreline springs along the east side of UKL beginning as early
as March and extending through May, with a peak in April (Buettner and Scoppettone 1990,
Barry et al. 2007b, Janney et al. 2009, Hewitt et al. 2012). One objective of the proposed action
is to fill UKL each spring to ensure there is an adequate water supply to meet irrigation and
environmental needs, including LRS and SNS and coho salmon, and consequently maximum
lake elevations are expected to be reached each year by April, or sometimes in May (Table 8.1
and Table 8.2).
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