Testosterone = early sexual maturation

Early sexual maturation of male fish weakens the immune system and leads to increased susceptibility to disease. In addition, both growth and slaughter quality are reduced. It can be difficult to detect signs of early sexual maturation – until the physiological changes have actually progressed to the point where both quality and fish welfare have been negatively affected.

 

Early sexual maturation can occur during both the first and second autumn in sea cages. In recent years, early sexual maturation has also become an increasing problem on land, for example in connection with the production of postsmolt and food fish in RAS facilities.

 

Testosterone levels are very low in small fish, but increase up to a hundredfold during sexual maturation. Testosterone is therefore a sensitive marker of sexual maturation in male fish, and the increase can be detected early in the fish's puberty.