Biological Opinions - Bureau of Reclamation

7.11.5 Conclusions Regarding the Capacity of the East Side Action Area to Support
LRS and SNS Conservation
The focus of this discussion is to determine how the baseline condition in the action area affects
the ability of multiple LRS and SNS populations to persist in a changing and adverse
environment. To assess this, we compared the baseline conditions with what the recovery plan
says are needed by the species to recover. The recovery strategy is intended to produce healthy
self-sustaining populations by reducing mortality, restoring habitat, including spawning, larval,
and juvenile habitats, and increasing connectivity between spawning and rearing habitats.
Recovery also involves ameliorating adverse effects of degraded water quality, disease, and
nonnative fish. The recovery goal is to produce naturally self-sustaining populations with
healthy long-term demographic traits and trends.
Currently, Clear Lake has a much smaller population of LRS than UKL, but larger than any other
water body, and a population of SNS on par with UKL. Suckers in Clear Lake are threatened by
drought and resulting low lake levels, and predation by birds; however, water quality (including
algal toxins) and disease are not known to be threats. Available information indicates that the
Clear Lake sucker populations have remained viable under the current management regime, and
we do not anticipate that this will change unless there is a prolonged drought more severe than
occurred in the recent POR.
There is also a population of SNS in Gerber Reservoir. Similar to Clear Lake, the effects of
fluctuating water levels on the SNS population there are not fully understood. Predation by
birds, adverse water quality, algal toxins, and disease are not believed to be existing threats for
this population. Available information indicates that the SNS population has remained viable
under the current management regime, and we do not anticipate that will change unless there is a
prolonged drought.
Both LRS and SNS reside in Sump 1A of Tule Lake but the majority is LRS. Neither species
has a self-sustaining population in this water body. Drought, severe winter conditions and warm
summer temperatures have the potential to cause low DO levels and threaten the species.
The Lost River is a highly altered system, which currently supports small sucker populations.
This area provides recovery benefits by adding redundancy, but currently does not support selfsustaining
populations because of habitat limitations.
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