Biological Opinions - Bureau of Reclamation

therefore, are part of the Project. Unscreened Project diversions in the Lost River pose an
unquantified threat to suckers, but this risk is likely small because of the low numbers of suckers
in the Lost River, especially young suckers that are most vulnerable to entrainment. Based on
this, the proposed action will likely contribute to entrainment of suckers in the Lost River, but
the effect will be small because of the low numbers of suckers present. However, since the
USFWS has determined that the LRS and the SNS in this area not necessary for recovery, the
proposed Project operations in the Link River would not be considered an adverse effect on the
condition of the species.
8.3.10 Summary of Effects of the Proposed Action to LRS and SNS in the Lost River
Subbasin Recovery Unit
The Lost River Recovery Unit is essential for the survival and recovery of the LRS and SNS
because it contains one of only two self-supporting LRS populations, and contains the largest
SNS population, and represents two of only three self-supporting SNS populations. This unit
provides resiliency and redundancy, two factors that are essential to all populations, but
especially those that are imperiled.
As described above, the proposed action is likely to have a variety of to the LRS and SNS
populations in the Lost River subbasin recovery unit. Some beneficial effects of the proposed
action are likely to include: (1) water storage in Clear Lake and Gerber Reservoir will provide
habitat for LRS and SNS in most years; and (2) any increase in flows in the Lost River during
the irrigation season will provide additional habitat.
Some compensatory elements of the proposed actions that will likely minimize adverse effects
including: (1) minimum elevations in Clear Lake, Gerber Reservoir, and Tule Lake Sump 1A
will minimize adverse effects of low lake levels; (2) the Clear Lake Dam fish screen will likely
reduce entrainment of juvenile and adult suckers; and (3) the 5 cfs (0.1 m 3 /sec) flow below
Gerber Dam during the non-irrigation season is likely to reduce mortality due to flow reductions
at the end of the irrigations season.
Adverse effects of the proposed action on LRS and SNS in the Lost River Subbasin Recovery
Unit are likely to include: (1) decreased habitat in Clear Lake and Gerber Reservoir in some
years; (2) lower water levels in Clear Lake during droughts will likely increase risk of pelican
predation and likely decrease body condition and productivity; (3) flow reduction/stoppage at the
Clear Lake and Gerber Reservoir Dams at the end of the irrigation season will eliminate or
reduce habitat downstream; (4) entrainment of suckers will likely occur at Clear Lake Dam and
Gerber Dam; (5) agricultural return flows from the Project are likely to reduce water quality in
the Lost River and Tule Lake.
Based on the best available information analyzed above, the USFWS concludes that adverse
effects from the proposed action to the LRS and SNS in Lost River Basin are likely to occur as a
result of habitat losses, poor water quality, entrainment, and increased vulnerability to pelican
predation. These effects are unlikely to limit the persistence of LRS and SNS in the Link River
Basin because the events that cause these effects are rare, occur at an insignificant level, are in
areas that are not considered necessary for recovery, or are part of operations that have not
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