3505

• UCREFRP Catalog Number: 3505
• Author: Rinne, J., et al., ed. 1986.
• Title: American Fisheries Society,
• USFW Year: Role o
• USFW - Doc Type: \
• Copyright Material: YES

are then transported to the tribal hatchery at
Sutcliffe where they are held in outside tanks and
troughs. Water is isolated from the hatchery proper
to preclude disease transfer from the wild. Fish
are tested here for ripeness by massaging the
abdominal area, and mature individuals are spawned
with a ratio of 3: 1 males to females. Eggs are
water-hardened for 60 minutes and placed in egg
jars. Spawned fish are weighed, measured, and
marked with Floy or Carlin tags prior to their
return to the lake. Immature females are injected
with carp pituitary extract and human chorionic
gonadotropin. Males are injected with 1 cc of
gonadotropin. Fish are tested for maturity the
following day and second injections are admin-
istered on the third day, if needed.
Water-flow to egg jars (1.5-gal capacity) is
maintained at 0.22 gal/min. Jars are filled to about
one-sixth of their volumes with eggs (approxi-
mately 40,000 or about 1.87 Ib). Culture jars are
treated in a I-minute static bath with 8.6 cc of
formalin, as needed, to inhibit fungus growth. At
the first sign of hatch, eggs and larvae are poured
into the shallow troughs, where the majority of
hatching then takes place.
Spawning in 1982 took place from April to June,
with a total of 17.7 million eggs taken (Table 2).
Because of the large egg production, a temporary
facility was set up at the second trout hatchery
for the lake (Numana). Survival to swim-up stage
was 10.9 million fry (61.6%). A summary of the
history of the cui-ui hatchery in terms of eggs to
stocking is shown in Table 2.
The significance of artificial propagation to
restoration efforts for the endangered cui-ui cannot.
be over-emphasized. The hatchery project is more
than an effort to increase recruitment to the
lacustrine population; it may, in fact, be the reason
that the species survives. Historic cui"ui,spawning

"

THREATENED & ENDANGERED FISHES

279.'

modification of the water supply, were incorpo-
rated prior to the 1982 hatchery operations. The
original hatchery water supply was from the well.
This supply was changed in July, 1981, when chilled
re-use water from the nearby Dunn Hatchery was
utilized to alleviate dramatic diurnal temperature
fluctuations encountered 'during incubation and
rearing. This make-up water is first sterilized by
an ultraviolet, system. Unlike most suckers, the
cui-ui prefers relatively cold incubation temper-
atures. Colder water aids in inhibiting the growth
of Saprolegnia during incubation and rearing to
swim-up. Hatchery water temperatures averaged
54.70F (:t 1.tF)1 apd 8.30F in diel fluctuation
during the 1982 incubation period.
Another important innovation was a new design
for incubation jars. The prototype jar included a
fine mesh screen on both the top and bottom.
The bottom screen was immediately above the
water inlet and accumulated air bubbles that
precluded a consistent upward flow of water. The
new design omits screens and contains a water
delivery tube that extends about two-thirds down
the length of an outer gas escape tube, which, in
turn, extends to the half-round bottom. Outflow
is through a tube near the top of the jar. This
design keeps eggs in constant rolling motion.
Finally, shallow aluminum troughs (4.5 inches
of water) were substituted for the circular tanks,
thereby permitting hatchery personnel to remove
fungused eggs and larvae before excess mortality
occurred.

Propagation Methods

Sexually maturing adults (age 4 + ) are obtained
with the aid of the FWS, Reno Fisheries Assistance
Office. Fish are captured by gill-netting in delta
regions by tribal personnel and by FWS personnel
from the Marble Bluff Dam and Fishway. Fish

i',.,<; ii ,: -f.'}!~

2.3

Ye.r

Table 2. Cu;-u; hatchery data, 1973-1982 (numbers ;n millions).

Totll eggs t.ken

No. of eggs h.tched

No. of I.nle stoc:ked or distributed

2.3

t:_
,

2.1
6.0 '
3.1
2.7
11.6
5.4
17.7

0.8
5.2
2.6
11.6

1.6
1.9 .
3.3
0.8
0.3
1.0
0.006
2.0
2.1
10.9