Our new Biological Assessment is out - Klamath Basin Crisis

Klamath Project Operations Biological Assessment
Endangered Suckers: Sucker Description, Life History, Habitat, Distribution, and
Abundance
In late spring, summer, and autumn, adult suckers generally occupy the northern
third of UKL (Bienz and Ziller 1987, Buettner and Scoppettone 1990, Golden
1969, Peck 2000, Perkins et al. 2000a, Reiser et al. 2001). However, suckers
apparently avoid shallow, clear water in UKL except when showing ill effects of
poor water quality (Bienz and Ziller 1987, Buettner and Scoppettone 1990, Reiser
et al. 2001), although some shortnose suckers congregate in the shallow area
between the Williamson River and Pelican Bay in early summer (Banish et al.
2007). Avoidance of shallow depths by adult suckers may be related to increased
vulnerability to predators while in shallow water. During poor water quality
events in UKL, adult suckers may avoid shallow water areas where water quality
is more suitable but lacking in cover, such as near Pelican Bay and the
Williamson River. There is evidence that adult suckers utilize Pelican Bay, an
area considered relatively shallow, during poor water quality events (Banish et al.
2007).
Spawning
Both Lost River and shortnose suckers primarily reside in lakes but may enter
tributaries to spawn (NRC 2004). Whether spawning occurs at shoreline areas in
lakes or in lake tributaries, both species begin spawning as early as February and
may continue through early June. The timing of spawning migration is somewhat
variable from year to year and apparently depends on age, species, sex, and
environmental conditions, most notably water temperature (Andreasen 1975,
Ziller 1985, Buettner and Scoppettone 1990, Klamath Tribes 1996, Perkins and
Scoppettone 1996, Markle et al. 2000 Sampling, 2000 Annual Report, Shively et
al. 2000 Shoreline, BLM 2000, Barry and Scott 2007, Barry et al 2007 Sprague).
Tributary spawning generally occurs in riffle areas with moderate current and
gravel to cobble sized substrates (Buettner and Scoppettone 1990). Spawning by
Lost River suckers in the Sprague River above Chiloquin Dam appears to be
concentrated at groundwater influenced areas (Tyler et al. 2007, Ellsworth et al.
2007).
In UKL, shoreline spawning occurs at several areas characterized by a mix of
gravel and coarse substrates, relatively shallow depths, and groundwater influence
from nearby springs (Buettner and Scoppettone 1990, Hayes et al. 2002, Barry et
al. 2007 UKL). Shoreline spawning areas in UKL are presently dominated by
Lost River suckers, although few shortnose suckers do appear to also spawn at
these areas (Hayes et al. 2002, Barry et al. 2007 UKL). Historically, shortnose
suckers probably spawned in greater numbers at shoreline spawning areas in UKL
(NRC 2004).
Lost River suckers and shortnose suckers typically spawn at night in shallow
areas with gravel substrate where eggs are broadcast or slightly buried (Bienz and
Ziller 1987, Buettner and Scoppettone 1990, 1991, Klamath Tribes 1995, Perkins
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