A 117-day feeding trial was conducted in ponds with
juvenile Australian red claw cray¢sh (Cherax quadricarinatus)
to evaluate the e¡ects on growth, survival,
body composition, and processing traits when fed
diets containing three di¡erent protein levels (22%,
32%, and 42%), and the e¡ects of feeding these
diets on pond water quality. Juvenile cray¢sh (mean
weight of 4.6 2.2 g) were randomly stocked into
nine 0.02-ha ponds at a rate of 500 per pond
(25000 ha 1
), and each diet was fed to three ponds.
There were two feedings per day, each consisting of
one-half of the total daily ration. At harvest, there
were no signi¢cant di¡erences (P40.05) in the individual
weight, percentage weight gain, or speci¢c
growth rate among treatments, which averaged
75.3 g, 1535%, and 2.38% day 1 respectively. Red
claw fed the 42% crude protein diet had signi¢cantly
higher (Po0.05) feed conversion ratio (7.34) compared
with cray¢sh fed diets containing 22% (5.18)
or 32% (5.13) crude protein, and had signi¢cantly
lower percentage survival (46.1%) compared with
red claw fed diets with 22% (61.1%) or 32% (58.2%)
protein. Total yield was signi¢cantly lower (Po0.05)
in red claw fed the 42% protein diet (640 kg ha 1
)
compared with red claw fed diets containing 22%
(920 kg ha 1
) or 32% (904 kg ha 1
) protein. Mean
total ammonia nitrogen (TAN) levels were signi¢-
cantly higher (Po0.05) in ponds with red claw fed
the 42% protein diet (0.55 mg L 1
) compared with
ponds with red claw fed diets containing 22%
(0.32 mg L 1
) or 32% (0.38 mg L 1
) protein. Mean
total nitrite concentrations in ponds with red claw
fed the 42% protein diet was signi¢cantly higher
(0.05 mg L 1
) compared with red claw fed diets containing
22% (0.01mg L 1
) or 32% (0.02 mg L 1
) protein.
These results indicate that a practical diet
containing 22% (as fed basis) protein may be adequate
for pond production of red claw when stocked
at the density used in this study, and that a diet containing
42% protein adversely a¡ected levels of TAN
and nitrite, possibly reducing overall survival of red
claw. Use of a diet with 22% protein may allow red
claw producers to reduce diet costs and thereby increase
pro¢ts.
Keywords: red c