The Eagle Lake Rainbow Trout (Oncorhynchus mykiss aquilarum), is the only rainbow trout
native to the east side of the Sierras. It was found only in Eagle Lake and it's tributary Pine Creek in
Lassen County. J.O. Snyder named this trout in 1917 using the latin name aguilarum, the latin term for
Eagle. This trout is unique in it's ability to withstand high alkalinity (Eagle Lake has a pH of 8.4 to 9.6).
The trout have characteristics more similar to coastal rainbow and interior redband trout than the nearby
Lahonton cutthroats. Since Pine Creek is only a few miles from the Pit River drainage, there is
speculation that these trout may have developed from rainbows in this area.
Eagle Lake has no outlet and the only place that the Eagle Lake trout can spawn is in Pine Creek. Over
the years, the creek became intermittent in it's lower reaches due to logging and grazing . The lush
meadows of Pine Creek was transformed into sagebrish flats making spawning runs impossible to it's
headwaters. By 1950, the Eagle Lake Trout was considered to be on the brink of extinction. A trapping
station was established by DFG at the mouth of Pine Creek. During the first year of trapping, six females
and 3 males were collected to provide the first spawned eggs. Notes from this period indicate that only
one female may have provided the initial eggs. Today the spawning facility at Crystal Lake Hatchery near
Burney, CA provides over 2.3 million eggs each year. Brood stock of the Eagle Lake trout are also
maintained at Mt. Shasta Hatchery where the fish are spawned artificially and about 4.2 million of eggs
are sent to other state hatcheries around the state for rearing and stocking other Sierran Lakes and
streams in addition to areas of New Zealand, Wyoming, and Montana. About 180,000 Eagle Lake trout are
returned to Eagle Lake by this program. A restoration program of Pine Creek is being pursued to restore
natural spawning since the hatchery rearing may be changing some of the original characteristics of the
fish. Some of the activities include fencing the creek and improving passage through the channel sections
of the stream. The DFG is also stocking some of the upper creek with Eagle Lake trout. A large
population of brook trout reside within the upper reaches of Pine Creek that may be causing increased
competition to the juvenile rainbows. The brooks may need to be eliminated in order to enable the
success of a natural spawning program.
The Eagle Lake Rainbow has a rounded nose. The fins and upper part of the body have large elongated spots.
The irregularly-shaped spots decrease towards the belly. There is a pinkish stripe along the lateral line.
The tail(caudal) fin edge is flat and has numerous, irregular spots. There is also a white tip on the dorsal,
pelvic, and anal fins.
J.O.Snyder described the following characteristics of the fish in 1917. Males at spawning time, "Body
above and down the sides nearly to the lateral line is a rich dark
olive, each scale brassy and very conspicuous. The sides below the olive region
and the ventral surface are deep coppery-red with bright metallic reflections.
The sides of the head are cherry-red, very rich in color. A trace of red beneath
the mandible; iris brassy. The pectorals are broadly and conspicuously edged
Females at spawning time were described as "It is light
olive above where each scale is silvery with greenish reflections. The sides are
lighter, the scales more green than those above, the ventral surface silvery,
tinted with pink. A very distinct pale reddish stripe extends along the side of the
body, mostly below the lateral line. The cheeks and opercles are red, the iris
orange. The ventrals and anal are suffused with red and distinctly edged with