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

C. Maximum specific feed consumption rates
It seems reasonable to assume the maximum growth rate is obtained on the maximum
ration. Figure 7 presents the average specific feeding rates for each of the three
experimental temperatures. A line has been fitted to each temperature data set, although
the data points following the weighing and measuring, at the midpoint of the experiment
were largely ignored when fitting these curves. It should be noted that the amount of feed
consumed each day varied greatly, the most usual pattern was a cycle of 6 or 7 days of
increasing amounts, and then a sudden drop followed by a repeat of the cycle. The origin
of this cycle is unknown, but was not considered a water quality problem due to the large
daily exchange of water, the relatively low level of nitrogenous waste products and the
maintenance of minimum dissolved oxygen concentrations. Thus it might be advisable to
feed slightly below the levels specified in the graph to prevent the possibility of
overfeeding.
Figure 7. Maximum specific daily feed ratio as a function of weight
Specific feed consumption (g/g/day)
D. Weights of females verse males
6
5
4
3
2
1
0
0 100 200 300 400 500 600
Weight (g)
13
26 deg C
29 deg C
32 deg C
Although the female fry were chemically sex reversed, which should have yield all males,
this procedure is not 100 % effective. At the termination of the experiment the fish were
weighed, measured and filleted. During the filleting process, the sex of fish was based on
their internal sex organs. Fifty-two out of a total of 579 fish were identified during the
filleting process as being female. The females were not distributed uniformly among the
experimental units, and thus a comparison of the mean female weight verses those of the
males could not be conducted because of the size and weight differences among the
treatments. Thus to compute an average size and weight difference, the measurements of
each female were compared to the average measurement of the males in that test unit. The