Resorption of spermatozoa in the sperm duct of rainbow trout during the post-spawning period.

Perliminary investigations on the loss of spermatozoa in the sperm duct of rainbow trout during the post-spawning period showed that the spermatozoa degenerated in situ in the duct lumen or were phagocytized there by free phagocytes and by the epithelial cells. Drasstic alterations occurring in the epithelium between March and April were characterized by excretory activity in March and intensive phagocytic activity in April when the process of sperm release had nearly stopped. A possible relation between the stuctural and functional changes in the sperm duct and endocrine balance were discussed.