TABLE 5. Fingerling production data for 6 stocking densities of tilapia fry over a 63-day feeding period. Each value is the mean of 3
 replicates.1


 Density (#/m2) Survival Total Weight Mean Weight Feed Actual Final Weight Gain
 Stocking Harvest (%) (kg/ha) (g) Conversion Feeding Feeding (kg/ha/day)
 Stocking Harvest (%) (kg/ha)Ratio Rate Rate
 (%body weight) (kg/ha/day)


 26 10 36.9a 210a 2.3a 2.61ab 13.6 25.3 3.3

 52 45 86.3b 769bc 1.7ab 0.87b 5.8 30.1 12.0

 78 48 62.2ab 671bc 1.5b 1.57b 8.0 41.8 10.4

 104 91 87.8b 1051 1.2b 0.75b 5.7 33.9 16.4

 130 42 32.7a 595c 1.4b 4.37a 15.3 102.7 9.1

 155 75 48.1a 984b 1.3b 2.29ab 10.4 93.6 15.2

 1
 Numbers within columns followed by the same superscript letter are not significantly different (P<0.05), based on
 Duncan's multiple range test.




 TABLE 6. Water quality of tanks stocked with 6 densities of tilapia fry during a 63-day feeding period.
 The mean and range are expressed in mg/liter unless otherwise specified.



 Stocking Density (#/m2)

Variable 26 52 78 104 130 155


 23.8 24.0 24.2 24.2 24.0 24.1
Temperature (oC) 22.0 25.5 22.0 26.0 23.0 26.0 22.5 26.0 22.0 26.0 22.0 26.0


 8.0 8.8 8.8 9.0 8.9 9.6
Dissolved Oxygen 5.2 12.5 4.1 13.0 4.5 10.4 4.4 11.7 2.4 14.8 3.5 14.0


 9.1 8.2 9.4 9.3 9.4 9.3
pH (units) 8.8 9.5 7.8 9.7 8.8 10.4 8.8 9.6 8.3 9.8 8.8 9.7


 866 839 848 875 850 891
Total Alkalinity 643 1076 598 1016 594 1109 580 1062 641 1030 658 1085


 0.13 0.14 0.16 0.15 0.16 0.14
Total Ammonia-Nitrogen 0.01 0.80 0.01 0.75 0.02 0.80 0.01 0.60 0.01 0.98 0.01 0.65


 0.84 0.90 1.13 1.16 0.96 1.14
Nitrite-Nitrogen 0.22 1.80 0.20 2.40 0.50 2.40 0.50 2.50 0.25 2.58 0.36 2.30

 21.9 22.2 34.0 24.1 20.6 20.4
Chlorophyll "a" (ug/liter) 7.9 62.4 4.5 79.3 4.5 71.8 3.1 60.8 7.9 70.3 7.9 44.2


tage of their body weight. For example, fish at an initial density
of 130/m2 and a final feeding rate of 15.3% had the second
highest growth rate throughout the first seven weeks (Figure 1).
 A length-frequency distribution of harvested fingerlings was
calculated for each stocking density and to determine if any of the
stocking densities resulted in the production of fingerlings that
were more uniform in size. The results illustrated in Figure 2
show that there was considerable variation in length among all
stocking densities. Fingerlings generally ranged from 3 to 9 cm in


VOL. XX-PROCEEDINGS of the CARIBBEAN FOOD CROPS SOCIETY


length at each density. The most frequently occurring length was
4 cm. The mean weight of 4-cm fingerlings ranged from 0.9 to
1.2 g. The distributions were skewed toward the shorter lengths.
Fish that were 7 cm long weighed approximately 5 g. The largest
fish at harvest was 10-cm long and weighed 16 g.
 In summary, the data indicates that as fish approach a mean
weight of 2 g in small static tanks, the feeding rate should be
greater than 6 % of body weight per day but should not exceed 40
kg/ha/day to maintain good growth and feed conversion.


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