REARING TILAPIA FOR TUNA BAIT 



Table 10. — Amount (in pounds) and cost of feeds supplied 

 tilapia brood stocks, 1959 



The adults generally fed avidly when produc- 

 tion of young was low but not when production 

 was high. 



Young 



The young fish were usually fed three times 

 daily in 1958, except on Sundays, with the amounts 

 varying with the number and age of the young. 

 Our intention was to give the fry all the feed they 

 could consume in order to obtain maximum 

 growth. Toward the end of summer, with about 

 500,000 young in the tanks, 45 pounds of feed were 

 supplied daily. 



Until they were 2-3 weeks of age, the very 

 young fish paid little attention to the feed offered 

 I hem, feeding principally on green algae ob- 

 tained from the walls of the tanks. The kinds, 

 amounts, and costs of feed supplied the young fish 

 in 1958 are listed in table 11. Until July, the 

 young fish were fed primarily on Clark's trout 

 feed and a wheat middlings-fish meal mixture 



(4:1 ratio). Starting in July this was supple- 

 mented with Purina trout feed. The use of 

 Clark's feed was discontinued in September. 



The young fi.sh were usually fed twice daily in 

 1959 with rations similar to those in 1958. The 

 very young to 3-week-old fish were fed on either 

 Purina starter or a middlings-fish-meal mixture 

 (4: 1 ratio). The 3- to 10-week-old fish were fed 

 on Purina fry feed. The 10-week-old and older 

 fish were fed a mixture of millrun-fish meal (4:1 

 ratio). The kinds, amount, and cost of various 

 feeds given the young in 1959 are listed in table 12. 



We did not attempt to record the amount of 

 feed supplied to the fish in each fry tank because 

 the tanks were too numerous and the fish varied 

 among tanks from newly hatched fiT to bait-size 

 fish. At each feeding the fish were given the maxi- 

 mum amount that they would consume, based on 

 past observations. The total weight of feed given 

 the young at each feeding was recorded. With 

 experience gained during the 2 years of operation, 

 we were able to set up a feeding schedule that ap- 

 peared adequate for favorable growth. The 

 schedule outlined here is suitable for a tank 6.5 X 

 11 feet containing aiiproximately 6,500 young. 

 The amounts specified should be given 2 or 3 times 

 daily as follows: 



First and second weeks, 0.3 ounces per feeding; 

 third week, 0.8 oz. : fourth and fifth weeks, 1.3 oz. ; 

 sixth and seventh weeks, 2.5 oz. : eighth week and 

 older, 5.9 oz. per feeding. With tlu-ee feedings a 

 day, 6 days a week for 12 weeks, 43.3 pounds of 

 feed were required to produce about 18 pounds 

 of bait-size fish, or 2.4 pounds of feed per pound 



