Effects of temperature and
salinity on weight gain, oxygen consumption rate, and growth efficiency in
juvenile red-claw crayfish Cherax quadricarinatus
M.E. Meade, J.E. Doeller, D.W. Kraus, S.A. Watts-2002
Journal of the World Aquaculture Society, 33(2):
188-198 (from Currents Contents)
Abstract :
Weight gain and metabolic rates, as determined by
oxygen consumption rates, were examined in juvenile Australian red-claw
crayfish Cherax quadricarinatus exposed to different temperatures 16-32°C
in 2°C increments) or salinities (0-30 ppt in 5 ppt increments). Mean
weight gain, ruching frequency. and survival (%) were dependent on
temperature and salinity. In freshwater (0 ppt), maximal weight gain and
molting frequency were observed at 28 C with maximal survival observed over
the temperature range of 24-30°C. Metabolic rates in freshwater were
temperature dependent (mean Q(10) = 2.44). Maximal weight gain and molting
frequency were observed at salinities of 0 and 5 ppt (28°C) however,
survival was reduced at salinities greater than or equal to 5 ppt. Metabolic
rates were not salinity dependent and did not differ significantly over the
salinity range from 0-20 ppt. Growth efficiencies, calculated by dividing
weight gain by total metabolic energy expenditure (i.e., weight gain +
metabolic rate), were highest at a temperature of 20°C (0 ppt) and at
salinities of 0 and 5 ppt (28°C). These data suggest that, at higher
culture temperatures, maximal weight gain of red-claw juveniles may be
reduced when food resources are limited. Maximal weight gain. at optimal
temperatures (28°C) with unlimited food supply, does not appear to be
affected by low salinity conditions. Because of the potential commercial
value of red-claw, culturists should be aware of the relationship between
environmental condition and metabolic energy requirements to ensure maximal
weight gain and survival of juveniles.
(Jacksonville
State Univ, Dept Biol, 700 N Pelham Rd, Jacksonville, AL 36265, USA)