TABLE OF CONTENTS Pages Symposium 1 - the National Sea ...

Figure 3. Cumulative feed consumption over the course of the experiment for tilapia fed
to satiation over the period of an hour, 4 times a day.
Cumulative feed consumed (g)
700
600
500
400
300
200
100
0
0 20 40 60 80 100 120 140
Time (d)
9
26 deg C
29 deg C
32 deg C
Figures 3 and 4 show that fish reared at 32 °C initially consumed more food than fish
reared at lower temperatures. Figure 4 illustrates the daily feeding patterns of the fish fed
to satiation. The higher the temperature, the more rapid the rise in daily feed consumption,
but the sooner it plateaus and the lower the height of the plateau. At the midpoint of the
experiment, the fish were removed, anesthetized, and individually weighed and measured.
It took more than two weeks for their appetite to fully recover from the trauma of this
procedure. This can be seen in Figure 4, by the dip in average feed consumed around day
70. The procedure used at the 5- and 15-week interval, where fish were removed,
counted and weighed as a group in a bucket of water, had only minimal effect upon the
subsequent feeding behavior of the fish.
The average weight change for each treatment is listed below in descending order of the
absolute weight gain. Statistical Analysis System (SAS) was used to perform a Duncan’s
Multiple Range Test at α = 0.05 to compare the significance of the changes in weight.
Since the fish fed to satiation consumed about the same amount of food cumulatively, it is
not surprising that the fish within the various feeding level treatments are indistinguishable
from each other, while there are differences across feeding levels. The exception being the
satiation and 87 % of satiation treatments that are almost statistically indistinguishable as
indicated by the A and B groupings. Worth noting is that within the feeding treatments,
the lower the temperature, the lower or better the FCR. Thus, within each feeding
treatment, the repositioning of the temperature treatments is primarily due to the
differences in the amount of food consumed, rather than the FCRs.