Evaluation of CASA system for predicting the motility of zebra mussel [Dreissena polymorpha Pallas] spermatozoa

A computer – aided semen analyzer (CASA) was used for monitoring some motility parameters of zebra mussel sperm after spawning for up to 1,5h at 22°C and after 24 hours of storage at 8°C. The mean percentage of motility (MOT) for sperm shortly after spawning was 70ą2.0 %, VSL = 31.8ą3.0 µm s-1, and VCL= 110.2ą6.4 µm s-1. The motility expressed as LIN was 27.7ą2.0 %, STR=44.5ą4.8 %, ALH=8.7ą2.0 µm, BCF=6.8ą2.0 Hz. The data demonstrate a consistent decrease in VSL (12.8ą 4.0), VCL (57.4ą 5.7), LIN (15.8ą 3.0) and ALH (1.1ą 0.23) values after 24 hours. No significant differences were found for % of MOT, BCF and STR parameters values during the time of experiment. We found CASA analyzer as a proper tool helpful to discerning the quality of zebra mussel semen samples.