The annual reproduction cycle in adult carp in Poland : ovarian state and serum gonadotropin level

BIENIARZ, K.; EPLER, P.; Breton, Bernard; Noc THUY, Luong

The annual reproduction cycle in adult carp in Poland : ovarian state and serum gonadotropin level

1978

BIENIARZ, K. | EPLER, P. | Breton, Bernard | Noc THUY, Luong

In environmental conditions in Poland, new vitellogenesis began in carp just after the spawning seascn. This phase was correlated with the maintenance of a high serum, gonadotropin level, which decreased and remained low when the temperature was also low ; oogenesis remained blocked at the stage attained before the drop in temperature and gonadotropin level. The rise of temperature in May increased GTH and ovarian responsiveness to hypophysation treatment. Although pituitary function seemed normal in some fish, there was no spawning even after hypophysation treatment. Resorbing oocytes were present during the whole year, and a minimum rate of GTH secretion would be necessary to prevent massive resorption. Animals were ready for a new reproduction cycle right after spawning ; this could not be achieved with the environmental conditions in Poland, namely the temperature. Existence of a limit temperature is discussed.

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