determination of gender and sexual maturity stages of reared great sturgeon (huso huso) using blood plasma sex steroid ratios

Gender and sexual maturity stages of great sturgeon (huso huso) were studied using blood plasma sex steroids hormones ratios (17 beta;estradiol (e2), testosterone (t) and 11ketotestostrone (11kt)}. one hundred sixty reared great sturgeon aged (112 years) with weight and length 0.45 to 49.65 kg and 36198 cm, respectively. for each gender, 80 individuals (20 fish in each maturity stage) were selected out of 650 fish. hormone concentrations measured with commercial kits. all samples analyzed in duplicate and a separate standard curve run for each elisa plate. the findings of this study showed that it is possible to separate male and female fish especially from the second sex maturation stage using t/e2 and 11kt/e2 hormone ratios. the results showed that the use of e2/t, e2/11kt ratios are very useful indices for sex determination and sexual maturity stages assessment in male reared great sturgeon, but t/11kt and 11kt/t ratios were not functional. based on the results, the use of t/e2 and 11kt/e2 ratios were preferable to e2/t and e2/11kt ratios for recognition of different sex maturation stages in male fish. these hormone ratios were used to determine different stages of male sexuality with more than 95% precision, and less than 30% for females. in addition, despite strong correlation between length and weight of fish with hormone ratios, sex could not identified through this parameter. the results of the present study revealed that some sex steroid hormones ratios can determine the sex and sex stages of reared great sturgeon especially in males with high accuracy.