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 Current 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, molting 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)