Masculinization of Tropical Eel Anguilla bicolor McClelland in Different Population Density

Abstract

In general, female eel dominates the results of catching eel in the river. Male fish dare rarely found in nature, therefore masculinization is necessary for obtaining in males.  The administration of 17α-methyltestosterone  to masculinize Anguilla bicolor McClelland .   It is a synthetic anabolic-androgenic steroid which has potential to endocrine disrupter that disturbed function of normal reproduction in human or animal. It urgently needed that a masculinization technique needs to study the use of an environmental factor. Population density is one of the environmental factors that influence gender determination (ESD-environmental dependent sex determination). This will result in increased cortisol secretion, which will further stimulate the synthesis of 11-KT steroids that affect male gonad differentiation. This study aims to induce masculinization in tropical eel Anguilla bicolor McClelland in different density. Three treatments and three replicates conducted the research. The treatments were one fish.48 L -1 , two fish.48 L -1 a nd three fish.48 L -1 .  Eels size was approximately similar, at 16,78 g±0,62 in weight, and 25,38 cm±0,15 in length were either culture in brackish water for eight weeks . The result s showed that density population treatment significantly i ncrease d the F i n Index ( P < 0.05), but no sign for E y e Index, GSI, HSI, and testosterone level. T he highest m a l e population (77,8%) achieves at t he highest density treatment, three fish.48 L -1 p opulation density. I t can be concluded , based on reproductive observations, population density does not affect gonad maturity/puberty, but t he high population density (3 fish.48 L -1 )stimulates Anguilla bicolor McClelland masculinization.