Long-term data on the induced spawning of common carp (Cyprinus carpio) at a large-scale hatchery were evaluated. Breeders at the farm prefer medium-sized fish with body weights between 4 and 8 kg. The number of females selected for propagation in the first period of the spawning season made up about half of the total number of females (47.5%). The average spawning ratio from the data of 2620 females receiving hormonal injections was 79.8%. From the data of egg production of 2086 females, the average pseudogonadosomatic index (PGSI) has been calculated as 16.3 ± 5.87% (mean ± SD) for the same period. The time of induction has a significant effect on both female responsiveness and the relative quantity of eggs released. The spawning ratio was significantly lower in the third period of the reproductive season, compared to those in the first and second periods. The mean pgsi for the third period was significantly lower than that for the first. The considerable decrease in both reproductive parameters by the end of the spawning season is attributed to ovarian atresia. The spawning ratio and the mean PGSI for the mirror and scaled varieties were similar.
|Number of pages||6|
|Journal||Acta Agronomica Hungarica|
|Publication status||Published - dec. 1 1999|
ASJC Scopus subject areas
- Agronomy and Crop Science