The Biology and Culture of Tilapias

Table 4. The spawning frequency and egg production of Sarotherodon aureus females in
interspecific spawning crosses with S. niloticus Ivory Coast males 50 g each over a 12-
month period (after Hulata et al. 1980 and Hulata unpublished data).

Total Average No. Average

egg eggd of interval

Female no. Date of spawning count spawn* spawns (days)

Date 1616- 417- 1618-

1 No. eggs ** 348 88 348 348 3

Interval 18 4 3 30

(days)

Date 718-

2 No.eggs ** 1

Interval

(days)

Date 517-

3 No.eggs ** 1

Interval

(days)

Date

4, 5, No. eggs 0

6, Interval

(days)

*Based on the number of eggs in fertile spawns only.

**Infertile spawns: eggs not counted.

Table 5. The spawning frequency and egg production of Sarotherodon niloticus Ivory

Coast females in interspecific spawning crosses with S. uureus males 50 g each over a

12-month period (after Hulata et al. 1980 and Hulata unpublished data).

Female no. Date of spawning

Total Average No. Average

egg eggs/ of interval

count spawn* spawns (days)

Date 2717- 1918- 719- 5110-

1 No. eggs 341 273 460 464 1,538 384 4

Interval 23 18 18 19

(days)

Date 312-

2 No. eggs 136 136 136 1

Interval

(days)

Date

3,4,

5, 6, No. eggs 0

Interval

(days)

*Based on the number of eggs in fertile spawns only.

**Infertile spawns: eggs not counted.