Biological Opinions - Bureau of Reclamation

Threat
Nature of
Threat
Life Stage
Affected
age-0
Primary Effect
Mitigating
Factor(s)
documented
especially at
population
level, but birds
are known
predators
References
2007, Roby
and Collis
2011
7.10.5 Effects of Ecosystem Restoration and Recovery Actions for the LRS and the
SNS
Since the early 1990s, the USFWS, Reclamation, NRCS, the State of Oregon, the Klamath
Tribes, The Nature Conservancy, Klamath water users, other partners, and private landowners
have been working to improve water quality and aquatic habitat conditions in the upper Klamath
River Basin to support the recovery of the LRS and the SNS. Major habitat restoration efforts
focusing on the endangered suckers have been completed or initiated. These include: (1)
enhancement of thousands of acres of wetlands adjacent to UKL and in the watershed above the
lake; (2) removal of Chiloquin Dam; (3) screening of the outlet of Clear Lake Dam; (4)
construction of a new fish ladder at Link River Dam; and (5) screening of the A Canal.
7.10.5.1 Wetland Restoration in UKL
The re-establishment of approximately 2,600 ac (1,050 ha) of shallow water habitat at the
Williamson River Delta, which is likely to be become emergent marsh (Elseroad 2004), is
expected to provide good habitat for larval suckers, and will perhaps increase survivorship and
reduce vagrancy and dispersal out of UKL where survival is currently minimal (Crandall et al.
2008; Hendrixson 2008; Markle et al. 2009; Erdman et al. 2010, 2011). Monitoring has shown
that larval suckers are extensively using a variety of microhabitats in the newly reconnected
wetlands; they have a greater gut-fullness, and in some years are larger, than larvae in the lake
(Crandall et al. 2008; Erdman and Hendrixson 2010, 2011). Additionally, restoration at the
Williamson River Delta altered the path water takes when it reaches the lake, which appears to
have affected the distribution of larvae, making it less likely they will be transported out of the
lake (Simon et al. 2012). On the potentially negative side: in some years habitat used by larval
suckers becomes dewatered by mid-July; a large number of nonnative fish, including six species
that could prey on larval suckers and three that could prey on juveniles, occur in the Williamson
River Delta; catch rates of age-0 suckers decline to near zero by September; and water quality in
areas with deep-water emergent and transitional wetlands is poor in late summer (TNC 2009,
Burdick 2012, Burdick and Hewitt 2012). Additionally, wetland habitats in the Delta provide
habitat for snails that could be one source of parasitic trematodes now infecting juvenile suckers.
Agency Lake Ranch and the Barnes properties (9,800 ac [4,000 ha]) along the northern and
northwestern shores of Agency Lake were acquired by Reclamation and used as water storage
areas, but are now managed as a part of the Upper Klamath NWR. Levees along these properties
could be breached within the next 10 years; however, because of subsidence, much of the
property will be too deep to maintain emergent wetland vegetation used by young suckers and
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