Effect of chronic confinement on sperm quality and male reproductive physiology in Eurasian perch, Perca fluviatilis.

Stress plays a key role in the ability of fish to perform reproduction. The aim of the present study was to examine the impact of chronic confinement applied during the final maturational period on sperm quality and reproductive physiology of perch. Perch breeders were reared in an outdoor recirculating system in 3 confinement conditions (0.07 m3, 0.5 m3 and 2 m3) in duplicate (except for 0.07 m3) at the same density (12 ind/m3). For each fish sperm and blood were sampled. Sex steroid hormones (17β-estradiol, 11-keto-testosterone and testosterone) were assayed by RIA. Sperm concentration was assessed by counting spermatozoa using a Burker’s cell. Sperm motility assessed with CASA system. In perch sexual hormone concentrations and sperm velocity were not significantly changed by confinement during the final maturational period, while sperm density decrease with confinement.