Quality and quantity of pikeperch (Sander lucioperca) spermatozoa after varying cold water treatments

Three groups of seven pond‐cultured pikeperch males, held under controlled conditions of low water temperature and for a varying photoperiod were injected with 500 IU kg⁻¹ human chorionic gonadotropin. Following a latent period of 72 h, sperm was collected. Stripping was on 26 March (Group A), 21 April (Group B), and 13 June (Group C). Spermatozoa was obtained from 85% fish in group B and from 42% of fish in group C. Mean volume of stripped semen for Group A was 0.64 ml, for Group B 1.07 ml, and for Group C 1.80 ml, while the mean concentration of spermatozoa was similar in all groups (15.73 ± 2.68–19.34 ± 3.87 10⁹ ml⁻¹). Group A spermatozoa showed the longest motile period (89.93 ± 10.20 s) and Group B the shortest (55.18 ± 10.46 s). The highest velocity at 15 s post‐activation was recorded in group A (220 ± 22.3 μm s⁻¹) and the lowest in Group B (159 ± 35 μm s⁻¹). Group C showed velocity of 187 μm s⁻¹. The results of our study showed that the length of the cold water period had no influence on spermatozoa quality, but did have an influence on the ability of males to produce sperm.