The Miller Lake Lamprey
was believed extinct after a chemical treatment in 1958 that targeted
lamprey and tui chub. Both species were extirpated from Miller Lake. The
lamprey population was later recognized to be a distinct species,
Lampetra minima (Bond and Kan 1973). It was the smallest lamprey
species in the world (maturing at less than 4 in), and at that time was
known only from Miller Lake, where it was extinct. In 1992, a
small lamprey captured in the Upper Williamson River was identified as a
Miller Lake Lamprey, and subsequent investigations have identified six
local populations of this lamprey in two small subdrainages of the Upper
Klamath Basin, the upper Williamson River and the upper Sycan River
above Sycan Marsh. The upper Williamson River contains four known
populations (Miller Creek, Jack Creek, Klamath Marsh, and mainstem
Williamson River above the marsh). Miller Creek, which drains Miller
Lake, is within the upper Williamson Watershed, but it goes sub-surface
in the pumice soils and does not reach the Klamath Marsh or Williamson
River. Jack Creek, a small northern tributary to the upper Williamson
River, is also generally disjunct from the mainstem Williamson River due
to low, intermittent surface flows in its lower reaches. The Upper Sycan
drainage contains two principal populations, Long Creek drainage and the
upper Sycan River drainage above Sycan Marsh. Lamprey are also assumed
present in the Sycan Marsh itself.
Miller Lake Lamprey feed on fish only as
adults. Ammocoetes have no eyes or teeth and are purely filter feeders,
burrowing in the sediment and feeding on suspended microorganisms and
algae. The ammocoete phase lasts about five years, during which time the
ammocoetes grow to around 150 mm. After transformation, adults enter a
predatory phase that generally lasts for less than a year. Adults feed
primarily on flesh that is gouged and rasped out of a small wound under the sucking disk. Adults apparently show little selectivity
for prey. The adult lampreys in Miller Lake historically fed on both tui
chubs and available salmonids in Miller Lake.
Following the extirpation of lampreys
from Miller Lake in 1958, a lamprey barrier was constructed in Miller
Creek to prevent recolonization of the lake from Miller Creek. The
barrier was constructed by the State of Oregon Game Commission in 1959
at the upstream extent of a short, high-gradient cascade in Miller Creek
approximately ½ mile downstream from the outlet of Miller Lake. In
efforts to conserve the Miller Creek population and to allow
recolonization of the lake, the barrier was removed in 2005.
Recent baseline surveys (August 2004) of lamprey ammocoetes in the Miller
drainage indicate that they are apparently limited to less than two
miles of low-gradient stream in lower Miller Creek. Allowing lampreys to
re-establish a population above the cascade in Miller Creek and Miller
Lake will aid in creating an additional buffer against stochastic events
that could otherwise eradicate this geographically limited population.
Since the removal of the barrier efforts are being taken to monitor the
population and its distribution. In the summer of 2006 biologists from
the Native Fish Investigations Project, ODFW, USFS, and Western Fishes
electrofished Miller Creek above and below the barrier site to detect
the presence of Miller Lake Lamprey and possibly indicate recolonization.
No lamprey were detected.
Many Lamprey species migrate based on pheromones or
scents given off by other lamprey. The lack of pheromones, as well
as high gradient water above the removed barrier, are hypothesized to be
the main factor inhibiting recolonization. The Miller Lake Lamprey
Science Team (MLST), a collaborative group consisting of staff from ODFW,
USFS, OSU, and Western Fishes, recommended that lamprey be physically
moved above the historic upstream barrier to encourage reestablishment.
In August 2010, members of MLST captured individual lamprey from Miller
creek and released them at three upstream locations. This effort will
continue over the next three years or until the population is
Annual Reports and Publications:
Gunckel S.L. and S. Reid. 2004.
Baseline survey of Miller Lake Lamprey (Entosphenus minimus) ammocoete distribution in the Miller Lake subdrainage.
Oregon Department of Fish and Wildlife
Miller Lake Lamprey
Conservation Activities - Reintroduction 8/4/2010.
ODFW Miller Lake Lamprey Conservation Plan
Lorion, C.M., D.F. Markle, S.B. Reid and M.F. Docker. 2000. Redescription of the presumed-extinct Miller Lake Lamprey, Lampetra minima.