Biological Opinions - Bureau of Reclamation

through seining and electrofishing (Kyger and Wilkens 2011b, 2012; Taylor and Wilkens 2013).
Continued monitoring (and fish salvage when fish are observed) in the A Canal forebay during
the week following initial salvage indicates very few fish remain in the forebay (Kyger and
Wilkens 2011b, 2012; Taylor and Wilkens 2013). Salvaged suckers are returned to UKL.
Adverse impacts to several hundred juvenile suckers due to stress are anticipated every year
during this salvage process, as well as from electroshocking, which is known to cause injuries
(Snyder 2003). However, observed mortality of salvaged suckers has been low because efforts
are made to ensure water quality remains high and fish are allowed to escape back into the Link
River prior to salvage (Taylor and Wilkens 2013). Additionally, initial studies on
electroshocking injury rates show that only a few percent of suckers suffer vertebral deformities
or other adverse effects, and efforts are underway to minimize electroshocking injuries by
appropriately adjusting methods (B. Phillips, USBR, pers. comm. 2013).
Stranding of suckers in canals prior to or in absence of fish salvage likely results in additional
mortality (Kyger and Wilkens 2012a), and because fish are crowded before and during salvage
and thus stressed, additional undetected mortality is likely. Mortality is likely to be highest in
years when sucker and other fish production is high; more fish present causes crowding stress
and makes it difficult to capture all of the suckers. However, it is anticipated that the adverse
effects of these operations will be minimized by salvage operations where suckers are moved to
areas where they are more likely to survive such as Tule Lake.
8.4.3 Effects of Lost River Diversion Channel Maintenance
Inspection of the gates and canal banks within the Lost River Diversion Channel occurs once
every 6 years (USBR 2012). Inspections require a drawdown of water within the channel and
can occur at any time of the year. According to the BA (USBR 2012), a drawdown of the
channel is coordinated with Reclamation fish biologists to ensure adequate water remains in
pools during short periods of low water levels, and pools are monitored to prevent stress to
stranded fish until flows return. When practical, to reduce impacts to suckers, Reclamation will
drawdown the Lost River Diversion Channel during late fall through early winter when fewer
suckers are likely present. During the drawdown of the channel, some adverse impacts to LRS
and SNS are likely, including an increase in predation by gulls as suckers are concentrated in
shallower water and increased stress, which if prolonged could affect survival. However,
adverse effects will likely be temporary (USBR 2012). Although temporary, the losses of habitat
as a result of this draw-down of the Lost River Diversion Channel will likely result in adverse
impacts to LRS and SNS in the channel and therefore are contrary to the conservation needs of
the species. Suckers would not be present in the Lost River Diversion Channel if they we not
entrained into the headworks of the channel. The effects of entrainment on LRS and SNS were
analyzed above under the analysis of entrainment in the UKL recovery unit.
8.4.4 Effects of Link River Dam Fish Ladder Maintenance
Gates to the Link River Dam fish ladder are exercised twice each year: once between January
and April and again between October and December (USBR 2012). While the gates are
exercised, the fish ladder is dewatered and the entire structure inspected. Fish are salvaged from
the ladder during dewatering and returned to either the Link River or UKL. These activities have
a temporary adverse impact to suckers in and adjacent to the ladder. Because the effect is short-
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