EN
The sperm collected from common and grass carp males was stored at 5oC, and activated with water of various temperatures (20, 26, and 30oC). Time of spermatozoa motility was measured. Motility decreased with time after milt collection. Common carp spermatozoa were active longer, up to 7080 s. In most series their activity was reduced after 24 hours. Spermatozoa of grass carp were active up to 3055 s, and their motility shortened already in 8 hours post collection. After 24 hours they were motile less than 10 s. The effect of temperature of activation was observed the spermatozoa were active for the longest time at 20oC. Spermatozoa motility time was also affected by temperature of storage. Even shortterm (15 min) keeping spermatozoa at 20oC shortened their motility time in both species, and after 2 hour storage common carp sperm motility was reduced by about 50%.