Data collection and analysis
Each temperature trial lasted for 48 h during which
continuous observation was made. The time food was
given and quantities of food given were recorded to
the minute. The surplus food left on the water surface
was recorded every 15 min.
Statistical evaluation was carried out by analysis
of variance on the feeding quantities in every 30 min
during the 48-hour period using SPSS 12.0 (SPSS
Science, Chicago, IL, U.S.A.). Daily feeding rate was
calculated using Kd=100(C/W) (Yin, 1993), where C
being daily feeding quantity, and W being the body
weight of the fish. To determine if water temperature
influenced the feeding rate, a one-way ANOVA, with
temperature as a factor and mass as a covariate, was
used to determine if feeding rate differed between
adult and young. If these results indicated a significant
effect, a LSD post hoc test was used to determine
which treatment groups were different. The difference
of P