Relation between gonadal hormones and sexual maturity of female Kutum

Relation between sexual maturity and levels of two main steroid hormones in gonads, 17- estradiol (E2) and testosterone (T) were studied by using histological and adioimmunoassay in female kutum Rutilus frisii kutum during spawning season of the southern Caspian Sea. The study was carried out from February to May 2008 using 105 migrated fish specimens catched from the River sefid-rood by various tools of catching
including (Gillnet, Cast net, Seine net and Sheyl or Kulham). The results revealed that changes in plasma levels of gonadal steroids, (E2) and (T) were closely correlated with ovarian development and increased in Gonadosomatic index (GSI) (P