Biology of Finfish and Shellfish (2+1)

4.1.3 Male reproductive organ (Testis)

In case of male fish, the reproductive organ consists of a pair of testes which lies ventral to the kidneys in the posterior region of the abdominal cavity. The testes remain attached to the body wall by mesorchia. The testes are free anteriorly but posteriorly they continue as sperm ducts which open into urinogenital papillae. A testis consists of seminiferous tubules which are lined by germ cells that produce spermatogonia. The spermatogonia undergo a number of maturation stages to develop motile sperms. This process is called spermatogenesis. In the space between the seminiferous tubules there are interstitial cells called Leydig cells, which are endocrine in function and produce male sex hormones called testosterone.