Biological Opinions - Bureau of Reclamation

2011) and increased adult spawning migrations upstream of the former Chiloquin Dam site
(Martin et al. 2013) have been documented.
7.10.5.2.1 Chiloquin Dam Removal
In 2008, Reclamation and the Bureau of Indian Affairs removed Chiloquin Dam located near the
confluence of the Sprague and Williamson Rivers. This action was expected to increase sucker
access to habitats in the Sprague River watershed as far upstream as Beatty where listed sucker
spawning and rearing have been documented (Ellsworth et al. 2007, Tyler et al. 2007).
However, monitoring results suggest that the upstream extent of spawning by the LRS and the
SNS has not substantially changed since the dam was removed, and most of their spawning
continues to occur below the former dam site (Ellsworth and Martin 2012).
7.10.5.2.2 A Canal Fish Screen and Fish Bypass Facility
Reclamation completed construction of a state-of-the-art fish screen at the entrance to the A
Canal in UKL in 2003 to reduce the high rates of fish entrainment known to occur at this
diversion site. LRS and SNS larvae and juvenile life stages were particularly vulnerable to
entrainment at A Canal before the screen was installed (Gutermuth et al. 2000a). The screen is
designed to protect most age-0 juveniles (greater than 1.2 in (30 mm) total length) and subadult
suckers that pass through the trash rack openings. Although the screen mesh openings are large
enough to allow larval suckers to pass, the hydraulic conditions that create positive sweeping
flows across the screen surface guide approximately 50 percent of the larvae into the bypass and
back into UKL (Bennetts et al. 2004). However, because the A Canal bypass discharges back
into UKL just upstream of Link River Dam, it is likely that most of the bypassed larval suckers
continue to disperse downstream out of UKL. The fate of juvenile and subadult suckers
bypassed at A Canal is also unknown, but more are likely to return to UKL, especially adults.
7.10.5.2.3 Link River Fish Ladder
Reclamation constructed a new vertical slot fish ladder at Link River Dam in December 2004.
The new ladder was specifically designed to allow suckers, which are not strong jumpers, to
easily swim through the slots and migrate above Link River Dam (Reclamation 2002b). Limited
monitoring of suckers has been conducted using radio and remote PIT tag receivers
(Reclamation 2007, Korson et al. 2008, Kyger and Wilkens 2011a). Between 2008 and 2011, a
total of 69 PIT-tagged suckers were detected passing antennas positioned in the fish ladder. The
numbers were about equally divided between the LRS and the SNS, although SNSs have
dominated catches in Lake Ewauna. Assuming there are 2,000 adult suckers in the Keno
Reservoir and that the tagged fish are representative of upstream movement by this population,
fewer than 1 percent of the adult LRS and SNS populations in Keno Reservoir move upstream
each year (Kyger and Wilkens 2010a). The reason for this is unknown.
7.10.5.3 Scientific Take Under Section 11 of the Endangered Species Act
Section 11 of the Act authorizes scientific permits for research or to enhance the survival and
recovery of listed species. The USFWS issues research permits under conditions that are
protective of sucker populations. To date, we have no information that supports a finding that
these research activities are detrimental to the affected sucker populations. Additionally, the
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