No abstract

Pikeperch, Sander lucioperca (L.), has been identified as one of the most perspective candidates for diversification of freshwater aquaculture. However, some aspects of production are still being developed, and controlled reproduction is one of the bottlenecks. The aim of the present study was to compare the effectiveness of different commercial spawning agents in the induction of final oocyte maturation (FOM) and ovulation in wild spawners. Within the study, four spawning agents [human chorionic gonadotropin (hCG), mixed human and horse gonadotropin (PG-600), carp pituitary (CPH) and mammalian GnRH analogue combined with metoclopramide (Ovopel)] in different thermal regimes (13 and 15°C) were tested. In both thermal regimes, the highest (P \ 0.05) ovulation rate among the treatment groups was obtained after stimulation with hCG (100 % in both cases). Latency time was the shortest in groups where CPH was used (2-3 and 3-4 days for 15 and 13°C) and was similar in the remaining groups (3-4 and 4-5 days for 15 and 13°C, respectively). Embryo survival was the highest in groups treated with hCG (78.9 and 81.3 % at hatching stage for 15 and 13°C, respectively). Hormonal stimulation did not significantly affect spermiation rate or spermatozoa motility (P [ 0.05). Based on the obtained results, hCG can be recommended for induction of FOM and ovulation in pikeperch. In addition, the thermal regime within the tested range seemed to have no effect on the reproduction outcome, and the application of lower temperature only prolonged the time of ovulation.