Physiology of Finfish and Shellfish (2+1)

3.1.5. Male reproductive system

In the male fish, the reproductive organ consists of a pair of testes. In the cartilaginous fishes they are usually elongated ovoid structures located anteriorly in the body cavity by means of a mesorchium.

In most of the bony fish, the testes are whitish or creamy coloured, elongated, lobulate organs attached to the dorsal body wall by mesochoria. A vas deferns or sperm duct arises from the posterior region of each elongated testis and leads to the urinary papilla which is located between the rectum and the urinary ducts.