RESUMEN
The common tench is an important thermophilic freshwater fish used for aquaculture diversification. This species is farmed in ponds as well as caught in the wild in many European and China. Artificial reproduction under controlled conditions is one of the most important part of modern aquaculture. In this study, two experiments were conducted in which the influence of hormonal agents (Ovopel and Ovaprim - experiment I) and the origin of the spawning stock (wild and pond-cultured - experiment II) on the success of reproduction in terms of ovulation rate (%), latency time (h), pseudo-gonadosomatic index (PGSI, %), hatching rate (%), abnormal larvae rate (%), and spawning efficiency coefficient (Se) were examined. While the wild fish could not reproduce in the absence of hormonal treatment with 0 % ovulation rate. In all tested hormonal treatment allowed to obtain high-quality eggs with hatching rates of over 83 %. Significant differences in latency time were observed among groups from different origins, such as differences in ovulation rate (79 % vs. 90 %, for pond-cultured and wild fish, respectively), PGSI (8.2 vs. 8.9), and hatching rate (63.8 % vs. 84.3 %), which showed significantly better quality in fish from the wild than those from pond culture. This means that when spawners of common tench of various origins are available, it is better to choose spawners from natural waters for artificial reproduction.
